USER INSTRUCTIONS
MODEL MCE325
PROGRAMMABLE USER STATION
9350-6464-00 Rev L, 11/2006
SHIPPING TO THE MANUFACTURER
PROPRIETARY NOTICE
The product information and design disclosed herein were
originated by and are the property of Telex Communications,
Inc. Telex reserves all patent, proprietary design, manufacturing, reproduction, use and sales rights thereto, and to any article disclosed therein, except to the extent rights are expressly
granted to others.
COPYRIGHT NOTICE
Copyright 2006 by Telex Communications, Inc. All rights
reserved. Reproduction, in whole or in part, without prior
written permission from Telex is prohibited.
WARRANTY NOTICE
See the enclosed warranty card for further details.
All shipments of product should be made via UPS Ground,
prepaid (you may request from Factory Service a different
shipment method). Any shipment upgrades will be paid by
the customer. The equipment should be shipped in the original packing carton. If the original carton is not available, use
any suitable container that is rigid and of adequate size. If a
substitute container is used, the equipment should be
wrapped in paper and surrounded with at least four (4) inches
of excelsior or similar shock-absorbing material. All shipments must be sent to the following address and must include
the Proof of Purchase for warranty repair. Upon completion
of any repair the equipment will be returned via United Parcel Service or specified shipper, collect.
Factory Service Department
Telex Communications, Inc.
8601 East Cornhusker Hwy.
Lincoln, NE 68507 U.S.A.
Attn: Service
CUSTOMER SUPPORT
This package should include the following:
Technical questions should be directed to:
Customer Service Department
RTS/Telex Communications, Inc.
12000 Portland Avenue South
Burnsville, MN 55337 USA
Telephone: 800-392-3497
Fax: 800-323-0498
RETURN SHIPPING INSTRUCTIONS
Customer Service Department
Telex Communications, Inc. (Lincoln, NE)
Telephone: 402-467-5321
Fax: 402-467-3279
Factory Service: 800-553-5992
Please include a note in the box which supplies the company
name, address, phone number, a person to contact regarding
the repair, the type and quantity of equipment, a description
of the problem and the serial number(s).
TABLE OF CONTENTS
Description & Specifications
1-1
Description . . . . . . . . . . . . . . . . . . .
General . . . . . . . . . . . . . . . . . . .
Features . . . . . . . . . . . . . . . . . . .
Front Panel Features . . . . . . . . . . . .
Channel Selector and Operation Buttons
Volume Controls . . . . . . . . . . . . .
Sidetone Nulling Trimmers . . . . . . . .
Connections, Inputs and Outputs . . . . . .
Front Panel . . . . . . . . . . . . . . . .
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1-1
1-1
1-1
1-2
1-2
1-2
1-2
1-2
1-2
Panel Microphone Jack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Rear Panel Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Intercom Lines . . . . .
External Program Input
Speaker Output . . . .
Auxiliary Connector . .
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Internal Programming and Adjustments . . . . . . . . . . . . . . . . .
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Intercom Line-Channel Configurations (DS1-DS3, J6, J7, J19 & J20)
Front Panel Setup Mode Lock-out (DS4) . . . . . . . . . . . . . . .
ISO (DS5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote Talk-off (DS7) . . . . . . . . . . . . . . . . . . . . . . . . .
VOX (DS8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Program Assignment – IFB Option (J4, J5, J16-J18) . . . . . . . . .
Balanced/Unbalanced Dynamic Microphone Selection (J24) . . . . .
Headphone Sidetone Trimmer Adjustment (R37) . . . . . . . . . . .
Speaker Dim Adjustment (R157) . . . . . . . . . . . . . . . . . . .
Mechanical Installation . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC Power and Fuse . . . . . . . . . . . . . . . . . . . . . . . . . .
Intercom Lines J8, J9, and J10 . . . . . . . . . . . . . . . . . . . .
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Connector Pin-outs . . . . . . . . . . . . . . . . . . . . . . . . .
Four-wire Output Termination . . . . . . . . . . . . . . . . . . .
Program Inputs, J14 and J15 . . . . . . . . . . . . . . . . . . . . .
External Speaker, J27 . . . . . . . . . . . . . . . . . . . . . . . . .
Auxiliary Connector, J22. . . . . . . . . . . . . . . . . . . . . . . .
Four-Wire Channel A and B Input . . . . . . . . . . . . . . . . .
Key outputs – Expanded IFB Option . . . . . . . . . . . . . . . .
Remote Microphone Switch . . . . . . . . . . . . . . . . . . . .
ISO Connection . . . . . . . . . . . . . . . . . . . . . . . . . .
External Headset . . . . . . . . . . . . . . . . . . . . . . . . . .
External Electret Microphone. . . . . . . . . . . . . . . . . . . .
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Programming . . . . . .
Power . . . . . . . . . .
Mounting Configuration .
MCE325 Specifications . . .
General . . . . . . . . .
Microphone Preamplifier.
Headphone Amplifier . .
Speaker Amplifier . . . .
Power and Mechanical .
Connectors . . . . . . .
MCS325 Specifications . . .
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. 1-3
. 1-3
. 1-4
. 1-4
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1-4
1-4
1-4
1-5
1-5
1-5
1-5
1-5
1-5
1-6
1-6
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. 2-1
. 2-1
. 2-2
. 2-5
. 2-5
. 2-5
. 2-5
. 2-6
. 2-6
. 2-6
. 2-6
. 2-6
. 2-8
. 2-8
. 2-8
. 2-8
. 2-8
. 2-8
. 2-9
. 2-9
. 2-9
. 2-9
. 2-10
. 2-10
. 2-10
. 2-10
. 2-11
Installation
2-1
i
Unswitched Microphone Output
External DC Power Source . .
Remote Speaker Mute Control.
Front Panel Headset Connections
Headset Requirements . . . .
Headset Connections . . . . .
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2-11
2-11
2-11
2-11
2-11
2-11
General . . . . . . . . . . . . . . . . . . . . . . . .
Operating Instructions . . . . . . . . . . . . . . . .
Momentary/Latching Button action . . . . . . . .
LED Indicators . . . . . . . . . . . . . . . . . .
Channel Selection. . . . . . . . . . . . . . . . .
Panel Mic/Headset Mic Selection . . . . . . . . .
Microphone On/Off . . . . . . . . . . . . . . . .
Speaker On/Off . . . . . . . . . . . . . . . . . .
Volume Adjustment . . . . . . . . . . . . . . . .
Front Panel Sidetone Nulling Trimmer Adjustment
Sending and Receiving Call Signals . . . . . . .
Using the Talk-Off Feature . . . . . . . . . . . .
Front Panel Programming . . . . . . . . . . . . . .
Activating Setup Mode . . . . . . . . . . . . . .
Menu Selection/Ending Setup. . . . . . . . . . .
Submenus. . . . . . . . . . . . . . . . . . . . .
Channel ID . . . . . . . . . . . . . . . . . . .
Four-channel Listen . . . . . . . . . . . . . .
Mono . . . . . . . . . . . . . . . . . . . . . .
Call Disable . . . . . . . . . . . . . . . . . .
Button Lock . . . . . . . . . . . . . . . . . .
Latch Disable . . . . . . . . . . . . . . . . .
Instant Mic . . . . . . . . . . . . . . . . . . .
Reset. . . . . . . . . . . . . . . . . . . . . .
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. 3-1
. 3-1
. 3-1
. 3-1
. 3-1
. 3-2
. 3-2
. 3-2
. 3-2
. 3-2
. 3-3
. 3-3
. 3-3
. 3-3
. 3-3
. 3-3
. 3-4
. 3-4
. 3-4
. 3-4
. 3-4
. 3-4
. 3-5
. 3-5
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Factory Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Corrective Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Panel Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cleaning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Test and Adjustment Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Test Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Supply Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Keying Output Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
USMB (Un-Switched Microphone Balanced) Frequency Response and Level Check
Frequency Response and Level Check, Mic to Line . . . . . . . . . . . . . . . . .
Four-Channel, Two-Wire Mode . . . . . . . . . . . . . . . . . . . . . . . . . .
Two-Channel, Four-Wire Mode . . . . . . . . . . . . . . . . . . . . . . . . . .
Sidetone Null Test and Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . .
True Sidetone Adjust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Level and Frequency Response Check, Intercom Channel to Headphone . . . . . .
Level and Frequency Response Check, Intercom Channel to Speaker. . . . . . . .
Level and Frequency Response, Program to Headphones and Speaker . . . . . . .
Program A to Left Headphone . . . . . . . . . . . . . . . . . . . . . . . . . . .
Program B to Right Headphone . . . . . . . . . . . . . . . . . . . . . . . . . .
Program to Speaker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IFB Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IFB B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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.
. 4-1
. 4-1
. 4-1
. 4-1
. 4-1
. 4-2
. 4-2
. 4-2
. 4-2
. 4-2
. 4-3
. 4-3
. 4-4
. 4-4
. 4-4
. 4-5
. 4-5
. 4-6
. 4-6
. 4-7
. 4-7
. 4-7
. 4-8
. 4-8
. 4-8
. 4-8
Operation
3-1
Maintenance
4-1
ii
IFB A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Level and Frequency Response Check, Four-Wire Input to Headphone
Four-Wire A Input to Left Headphone . . . . . . . . . . . . . . . .
Four-Wire B input to Right Headphone. . . . . . . . . . . . . . . .
Panel Mic to Channel Test . . . . . . . . . . . . . . . . . . . . . . . .
Carbon Mic to Channel Test . . . . . . . . . . . . . . . . . . . . . . .
VOX Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mic Kill Receive Test. . . . . . . . . . . . . . . . . . . . . . . . . . .
Mic Kill Transmit Test . . . . . . . . . . . . . . . . . . . . . . . . . .
Call Transmit Test . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Call Receive Test . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ISO Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote Mic Switch Test . . . . . . . . . . . . . . . . . . . . . . . . .
Program Lockout Test . . . . . . . . . . . . . . . . . . . . . . . . . .
Noise Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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. 4-9
. 4-9
. 4-9
. 4-9
. 4-10
. 4-10
. 4-10
. 4-10
. 4-11
. 4-11
. 4-11
. 4-12
. 4-12
. 4-12
. 4-12
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. 5-1
. 5-1
. 5-2
. 5-3
. 5-3
. 5-3
. 5-13
Parts Lists
Packaging Assembly (9000-6464-00) . . . . . .
Final Assembly, MCE325 (9010-6464-00) . . . .
Front Panel Assembly (9020-6261-00) . . . . . .
Back Panel Assembly (9020-6262-00) . . . . . .
Heatsink Assembly (9020-6324-00) . . . . . . .
Main PC Board Assembly (9030-6245-01) . . . .
PC Board Assembly, Front Panel (9030-6246-00)
5-1
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Diagrams
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6-1
iii
iv
S
E C T I O N
DESCRIPTION & SPECIFICATIONS
CHAPTER1
Description
General
The MCE325 is a four-channel, programmable intercom station. It may be used as a headset
station or, with the addition of the MCS325 Modular Speaker, as a speaker station. It may be
mounted in a console or equipment rack via optional mounting kits.
The MCE325 can be used with either two-wire or four-wire intercom lines, or a combination of
both. In this manual and in the labeling on the MCE325, references to channels 1, 2, 3, and 4
indicate two-wire lines; references to four-wire A and four-wire B indicate four-wire lines.
The MCE325 can be interfaced to a variety of external devices including external program
sources, two-way radios, paging systems, and satellite circuits. Some typical applications are
shown in Figure 1.2 through Figure 1.10.
Features
Features of the MCE325 include:
• Call Signaling: Call signaling is accomplished using an inaudible (20 kHz) signal to activate a
call indicator LED.
• Remote “talk-off”: Active, unattended remote station microphones may be deactivated by
momentarily injecting an inaudible (24 kHz) signal into the corresponding intercom line. The
MCE325 can send and receive “talk-off” signals.
• VOX circuit: The MCE325 may be programmed for voice activation of the microphone.
• Simple IFB: Program audio assigned to a channel is interrupted during talk.
• External device keying: External devices, such as two-way radios, speaker mute relays, or
paging systems may be activated through key outputs at the auxiliary connector on the rear
panel. The key outputs may also be used to expand the simple IFB function, allowing any one
of a number of MCE325 stations to interrupt the program source and talk on the line.
• Microphone limiter: The microphone preamplifier circuit contains a limiter, which helps to
equalize voice levels.
• Fully programmable: Retains programming even when power is shut off.
1-1
Front Panel Features
Channel Selector and Operation Buttons
These buttons have two modes of operation: standard operating mode and program, or setup,
mode. The printing on the face of each button indicates its function in standard operating mode;
printing under each button indicates its setup mode function. (See Section 3 for operation and
programming instructions.) An LED located above each button provides status information.
NOTE
The MCE325 is factory pre-programmed for two-channel operation, with each channel having
one talk and one listen button. However, the MCE325 may also be programmed so that each
channel selector button controls both talk and listen for a single channel, permitting operation of
up to four intercom channels. Additionally, users may wish to customize the identification of
channels. With this in mind, a button kit has been supplied with the MCE325 to allow you to
customize the button labeling to suit your particular application. Figure 1.11 shows the available
button caps as well as some typical button configurations.
The standard buttons are opaque. As a result, the front panel LED’s may not be visible when
viewing the MCE325 from a low angle (such as when it is mounted high in an equipment rack).
As a remedy for this problem, clear buttons are available that allow the LED light to pass through.
(Order RTS™ part no. 9000-2698-800)
Volume Controls
CH1 (VOL 1): This control adjusts the volume of channels 1 and/or 3 to the left headphone when
stereo headphones are used. It adjusts the mono mix level of these channels when monaural
headphones or an external speaker is used.
CH2 (VOL 2): This control adjusts the volume of channels 2 and/or 4 to the right headphone
when stereo headphones are used. It adjusts the mono mix level of these channels when monaural
headphones or an external speaker is used.
PGM VOL: This control adjusts the mono mix of program A and program B (input at the rear
panel and assigned via internal programming) to the headphones and external speaker.
Sidetone Nulling Trimmers
These trimmers are adjusted to prevent acoustic feedback when using a panel microphone along
with an external speaker.
Connections, Inputs and Outputs
Front Panel
DYNamic MIC HEADSET: This connector accepts a stereo-earphone, dynamic-microphone
headset (with or without a mic on/off switch).
CARBon MIC HEADSET: This connector accepts a standard 3-conductor, ¼-inch phone plug.
The necessary phantom power is provided to power a carbon microphone or its electronic
equivalent.
Panel Microphone Jack
The MCE325 may be optionally fitted with a gooseneck panel microphone by removing the
blanking plug located in the upper-right corner of the front panel. The panel microphone jack
accepts specially made gooseneck microphones (MCP-90 series), which are available from RTS.
1-2
MCE325 User Instructions
Figure 1.1
MCE325 front and rear panel features.
Volume
Controls
Channel Selector
and
Operation Buttons
CH 1
1
TALK
1
LISTEN
2
TALK
2
LISTEN
Mono
Call Disable
SPKR
ON
MIC
ON
Channel ID 4-Ch Listen
CALL
PANEL
MIC
Dynamic-Mic
Headset
Connector
Panel
Mic
Jack
CH 2
Setup Mode Button Lock Latch Disable Instant Mic
Sidetone Nulling
Trimmers
Program
Volume
Fuse
AC Power Cord
Carbon-Mic
Headset
Connector
Speaker
Jack
J27
J22
Auxiliary
Connector
J15
J14
External
Program
Jacks
PUSH
J10
PUSH
J8
J9
Intercom
Line Connectors
Rear Panel Features
Intercom Lines
Connectors J8 and J9 are parallel-wired for loop-through connection to additional stations. These
connectors are used either for two-wire channels 1 and 2 input/output, or four-wire channel A
output. (The four-wire channel A input is connected at the auxiliary connector.)
Connector J10 is used for two-wire channel 3 and 4 input/output, or four-wire channel B output,
but no loop-through connector is provided for these channels. (The four-wire channel B input is
connected at the auxiliary connector.)
The MCE325 presents a bridging impedance of 10,000 ohms to the intercom line, and is designed
for use with intercom lines having a 200-ohm line terminating impedance. A 200 ohm termination
plug is supplied (connected to J10) to prevent channels three and four from oscillating when the
MCE325 is in two-channel mode.
External Program Input
Two ¼-inch phone jacks are provided for external program input. The station accepts line-level,
balanced input. The two program inputs are mixed internally, and may be assigned (through
internal programming) to right headphone, left headphone, external speaker, or any combination
of these. In addition, program A may be assigned (through internal programming) to two-wire
channel 3 or four-wire channel A; program B may be assigned to two-wire channel 4, but cannot
1-3
be assigned to a four-wire channel. The program assigned to channels is interrupted during talk
output.
Speaker Output
A ¼-inch phone jack is provided for connection of an external speaker (8-ohms minimum
impedance). The speaker output is compatible with the MCS325 speaker.
Auxiliary Connector
Standard Options on the 25-pin, female, D-Sub connector are:
1 Unswitched microphone output
2 ISO connection to a VCP6A/VCP12A/VCP12B
3 Microphone on/off switch
4 Remote headset
5 Remote panel microphone
6 Separate inputs for +10 to +15 volts DC, and +17 to +24 volts DC
7 Common/ground circuit
8 Four-wire channel A and B inputs
9 Remote speaker mute
10 Key outputs
Programming
Three methods of programming are used:
1 Front panel programming via the channel selector and operation buttons.
2 Internal programming via circuit board DIP switches.
3 Internal programming via circuit board jumpers.
The most commonly programmed options are assigned to the front panel for convenience.
Detailed information on internal programming is provided in Section 2, Installation. Detailed
information on front panel programming is provided in Section 3, Operation.
Power
The MCE325 is designed for local powering, and is supplied ready for use with either 115 or 230
VAC (but not both). The unit may also be powered from an external DC source connected at the
Auxiliary (J22) connector on the rear panel. For information on changing the AC supply voltage
configuration, or using DC power, see Section 2.
Mounting Configuration
Mounting configurations are illustrated in Figure 2.3 and include rack mount speaker station,
console mount headset station, rack mount headset station, desk top headset station, and portable
speaker station. Some mounting configurations may require a remotely located microphone or
headset. These may be connected to the Auxiliary connector (J22) on the back of the unit.
1-4
MCE325 User Instructions
MCE325 Specifications
General
Bridging Impedance (to line)
10,000 ohms typical
Noise Contribution to 200-ohm Line
-90 dBu
Call Signal Frequency
20 kHz, crystal controlled
Talk-off Frequency
24 kHz, crystal controlled
Microphone Preamplifier
Maximum Voltage Gain
54 dB
Frequency Response
100 Hz to 8,000 Hz, ±3 dB
Input Impedance
1,000 ohms
Limiter Range
30 dB
Headphone Amplifier
Maximum Voltage Gain
30 dB
Frequency Response
100 Hz to 8,000 Hz, ±3 dB
Headphone Impedance
50 to 600 ohms
Output Power
150 mW into 50 ohms
Output Voltage Level
8 Vp-p
Speaker Amplifier
Maximum Voltage Gain
30 dB
Frequency Response
100 Hz to 8,000 Hz, ±3 dB
Speaker Impedance
8 to 16 ohms
Output Power per Amplifier
5W into 8 ohms
Output Voltage Level
16 Vp-p
Power and Mechanical
Power Requirements
115 to 230 VAC, 20 VA max,
12 to 25 VDC, 100 to 125 mA quiescent, 900 mA max
Dimensions
1.72” H x 8.2” W x 8” D (44 mm x 208 mm x 203 mm)
Weight
4.25 lbs (1.93kg)
Material/Finish
finish
Thermo-plastic front panel, aluminum case, light gray
1-5
Connectors
Intercom Line Connector
XLR type, 3-pin (male-female loop through on two-wire
channel 1 and 2, or four-wire channel A; Female only on
two-wire channel 3 and 4, or four-wire channel B
Dynamic Mic
XLR type, 6-pin female
Carbon Mic
¼-inch phone jack, 3-circuit
Auxiliary Connector
25-pin, female, D-Sub
Program Inputs
¼-inch phone jack, 3-circuit
Speaker Output
¼-inch phone jack, 3-circuit
Panel Mic
¼-inch phone jack, metal busing, 3-circuit
MCS325 Specifications
The MCS325 is designed for use with MCE325, but may also be used as a general-purpose
monitor for program material.
Impedance
8 ohms (DCR5.5 to 7 ohms)
Power Rating
5W RMS continuous
Sensitivity
90 dB ±2 dB/2.83 volts/one meter on axis averaged over
one octave bands centered at 250 Hz, 500 Hz, 1 kHz,
2 kHz, 4 kHz, and 8 kHz when enclosed in a sealed box
of 1.3 liters volume.
Frequency Response
200 Hz to 10 kHz ±4 dB on 1/10 octave measurement in
1.3 liter sealed box.
Free Air Resonance
200 Hz to 250 Hz
Distortion
Less than 10% @ 5W at resonance.
Stray Magnetic Field
Less than 1 gauss at 1 cm from chassis.
Mechanical Noise
Unit to be free of buzzes and rattles at 5 W sine wave
input from 100 Hz to 10 kHz.
Figure 1.2
1-6
Standard two-channel, two-wire configuration.
MCE325 User Instructions
Figure 1.3
Standard four-channel, two-wire configuration.
Figure 1.4
A four-channel, two-wire configuration with two channels used for IFB’s.
Figure 1.5
Configuration for one or two two-wire channels and one four-wire channel.
1-7
1-8
Figure 1.6
Standard two-channel, four wire configuration.
Figure 1.7
Multiple interconnected stations in four-channel, two-wire configuration with two channels
used for IFB’s.
MCE325 User Instructions
Figure 1.8
Multiple interconnected stations using one four-wire intercom channel and two two-wire
channels for IFB’s.
Figure 1.9
A four-channel, two-wire configuration with two channels used for IFB’s (shown with TELCO
interface).
1-9
Figure 1.10 Configuration for an ENG truck using one four-wire intercom channel and two two-wire
IFB’s.
1-10
MCE325 User Instructions
Figure 1.11 MCE325 button configurations.
1-11
1-12
MCE325 User Instructions
S
E C T I O N
INSTALLATION
CHAPTER2
Internal Programming and Adjustments
WARNING
Hazardous voltages exist inside this equipment. Disconnect the AC line cord before
opening the equipment or attempting any internal programming or adjusting.
General
Prior to installing the MCE325, it may be necessary to change some of the internal programming
to suit your particular application. Table 2.1 and Table 2.2 list the functions for the DIP switches
and jumpers which are used for internal programming. Also shown are the default settings that
were pre-programmed at the factory.
If your application requires settings that are different from the defaults, you will have to remove
the top cover of the unit (see Figure 2.1) and make the required changes. If you do change the
internal programming, it may be useful to note the changes for future reference.
The locations of the DIP switches and jumpers are illustrated in Figure 2.2. DIP switch
programming is accomplished by setting switches to the “off” or “on” positions. Jumper
programming is accomplished using shorting jumpers. By inserting the jumpers to short the
appropriate pins, a function is either assigned or not assigned. Pin 1 of each jumper is indicated by
a square symbol in Figure 2.2 for reference when making changes. Also shown in Figure 2.2 are
trimmers for adjusting the sidetone and speaker dimming levels. Usage of the DIP switches,
jumpers, and level trimmers is described in the following paragraphs.
2-1
Figure 2.1
Top cover removal.
Intercom Line-Channel Configurations (DS1-DS3, J6, J7, J19 & J20)
The four channels of the MCE325 may be assigned to intercom lines in a variety of ways.
Channel assignment is determined by the settings of DIP switches DS1 through DS3 and jumpers
J6, J7, J19, and J20. There are six possible intercom line configurations. These are listed in Table
2.3 together with the proper DIP switch and jumper settings for each.
Table 2.1
DIP switch functions and default settings.
Switch Number Switch Function
NOTE
Default Setting
DS1
four-wire CH A output not installed (off), four-wire CH A output installed Off
(on)
DS2
four-wire CH B output not installed (off), four-wire CH B output installed Off
(on)
DS3
two-channel mode (off)*, four-channel mode (on)
Off
DS4
Front panel setup lock-out disabled (off), Front panel setup lock-out
enabled (on)
Off
DS5
Listen and talk muted during ISO (off), Talk only muted during ISO (on) Off
DS6
Not used
Off
DS7
Talk-off transmit disabled (off), Talk-off transmit enabled (on)
On
DS8
VOX disabled (off), VOX enabled (on)
Off
The terms “two-channel mode” and “four-channel mode” apply only to two-wire lines. In twochannel mode, each two-wire line uses two channel selector buttons: one for talk and one for
listen. In four-channel mode, each two-wire line uses one channel selector button for both talk and
listen.
The two-channel mode should be selected under only two circumstances:
1 When only one or two two-wire lines are connected to channels one and two only.
2-2
MCE-325 User Instructions
2 When a two-wire line is connected to channel one and a four-wire line is connected to channel
B.
For all other intercom line configurations that use two-wire lines, DS3 must be set to the “on”
position for four-channel operation.
Table 2.2
NOTE
Jumper functions and default settings.
Jumper Number Jumper Function
Default Setting
J4
Assigns PROGRAM A input to two-wire CH 3 or four-wire CH B.
Not assigned: pins 2 & 3 shorted.
Assigned: pins 1 & 2 shorted (IFB to CH 3).
Not assigned
J5
Assigns PROGRAM B input to two-wire CH 4.
Not assigned: pins 2 & 3 shorted.
Assigned: pins 1 & 2 shorted (IFB to CH 4).
Not assigned
J6
Selects two-wire CH1 and CH 2, or four-wire CH A output. (See J19 Two-wire operation
for CH A input.)
CH1 and CH 2 selected: pins 2 & 3 shorted.
Four-wire CH A output selected: pins 1 & 2 shorted.
J7
Selects two-wire CH 3 and CH 4, or four-wire CH B output. (See J20 Two-wire operation
for Ch B input.)
CH 3 and CH 4 selected: pins 2 & 3 shorted.
Four-wire CH B output selected: pins 1 & 2 shorted.
J16
Assigns mono mix of the PROGRAM A and B inputs to the left
headphone.
Not assigned: pins 2 & 3 shorted.
Assigned: pins 1 & 2 shorted.
Assigned
J17
Assigns mono mix of the PROGRAM A and B inputs to the right
headphone.
Not assigned: pins 2 & 3 shorted.
Assigned: pins 1 & 2 shorted.
Assigned
J18
Assigns mono mix of the PROGRAM A and B inputs to the speaker. Assigned
Not assigned: pins 2 & 3 shorted.
Assigned: pins 1 & 2 shorted.
J19
Selects four-wire CH A input. Off (not used): pins 2 & 3 shorted.*
On when LISTEN 1 button is on: pins 1 & 2 shorted.
Always on: pins 3 & 4 shorted.
Off
J20
Selects four-wire CH B input. Off (not used): pins 2 & 3 shorted.*
On when LISTEN 2 button is on: pins 1 & 2 shorted.
Always on: pins 3 & 4 shorted.
Off
J24
Selects unbalanced or balanced dynamic mic input.
Unbalanced: pins 2 & 3 shorted.
Balanced: pins 1 & 2 shorted.
Unbalanced mic input
*J19 and J20 jumpers should be in “off” positions when two-wire lines are used.
2-3
Figure 2.2
2-4
Internal DIP switches, jumpers and level trimmers.
MCE-325 User Instructions
Table 2.3
Internal programming for the various intercom line configurations.
DIP SWITCHES
JUMPERS
DS1
J6
DS2
DS3
J7
J19
J20
Configuration 1: Two 2-wire lines (CH 1& CH 2). (Default configuration.)
Off
Off
Off
Pins 2 & 3 shorted Pins 2 & 3 shorted Pins 2 & 3 shorted Pins 2 & 3 shorted
Configuration 2: Three or four 2-wire lines (CH 1, CH 2, CH 3, CH 4).
Off
Off
On
Pins 2 & 3 shorted Pins 2 & 3 shorted Pins 2 & 3 shorted Pins 2 & 3 shorted
Configuration 3: One 2-wire line (CH 1); One 4-wire line (CH B).
Off
On
Off
Pins 2 & 3 shorted Pins 1 & 2 shorted Pins 2 & 3 shorted Pins 1 & 2 shorted
Configuration 4: Two 2-wire lines (CH1 & CH2); One 4-wire line (CH B).
Off
On
On
Pins 2 & 3 shorted Pins 1 & 2 shorted Pins 2 & 3 shorted Pins 1 & 2 shorted
Configuration 5: Two 2-wire lines (CH 3 & CH4); One 4-wire line (CH A).
On
Off
On
Pins 1 & 2 shorted Pins 2 & 3 shorted Pins 1 & 2 shorted Pins 2 & 3 shorted
Configuration 6: Two 4-wire lines (CH A & CH B).
On
NOTE
On
On
Pins 1 & 2 shorted Pins 1 & 2 shorted Pins 1 & 2 shorted Pins 1 & 2 shorted
See Table 3.1for a summary of how the channel selector buttons work for the various
configurations. The MCE325 is typically supplied with a termination plug inserted into J10. This
plug terminates CH 3 and CH 4 with 200 ohms to prevent oscillation when these channels are not
used. When the channels are used, this termination plug should be removed.
Front Panel Setup Mode Lock-out (DS4)
DIP switch DS4 may be set to lock out the front panel programming and prevent changes. Front
panel programming is described in Section 3, Operation.
ISO (DS5)
The MCE325 may be used with an RTS Model VCP6A, VCP12A, or VCP12B Control Station to
permit private conversation between the MCE325 operator and a camera operator. When ISO
mode is engaged, either talk, or talk and listen (depending on the setting of DS5) for all other
channels connected to the MCE325 will be muted, and a private line will be established between
the MCE325 operator and the camera operator. See “ISO Connection” for wiring information.
Remote Talk-off (DS7)
The MCE325 is capable of generating and transmitting an inaudible, 24 kHz signal on an
intercom channel. This signal is used to turn off the microphones on any remote stations on the
channel (stations with remote talk-off feature only). This feature is useful when an unattended
user station with an activated microphone is introducing unnecessary noise into a line. DIP switch
DS7 enables/disables this feature. When remote talk off is enabled, the talk-off signal is activated
using the CALL button on the front panel. (for Operation see “Using the Talk-Off Feature”.)
VOX (DS8)
DIP switch DS8 turns the voice activated microphone circuit on or off. Voice activation can be
used with the panel microphone, a headset, or a remote microphone connected at the rear panel.
(There is no adjustment for VOX sensitivity.)
2-5
Program Assignment – IFB Option (J4, J5, J16-J18)
Jumper J4 assigns PROGRAM A to two-wire CH 3 or four-wire CH B with interrupt during talk
(IFB A). Jumper J5 assigns PROGRAM B to CH 4 with interrupt during talk (IFB B).
(PROGRAM B is not used in four-wire mode.)
Jumpers J16, J17, and J18 assign the mono mix of both program inputs to the left headphone,
right headphone, and speaker respectively. Program volume to the headphones and speaker is
controlled by the PGM VOL control on the front panel.
See Table 2.2 for Jumper settings. See Figure 2.2 for locations of jumpers.
Balanced/Unbalanced Dynamic Microphone Selection (J24)
The MCE 325 may be used with headsets having either a balanced or unbalanced dynamic
microphone. The MCE325 is pre-programmed for use with an unbalanced microphone by
shorting J24 pins 2 and 3. For balanced microphones, remove the shorting jumper and reinstall it
to short pins 1 and 2.
Headphone Sidetone Trimmer Adjustment (R37)
The headphone sidetone trimmer (R37) adjusts the loudness of your own voice heard in your
headset when the microphone is on and the speaker is off. (It does not affect the actual level heard
on the intercom lines.) This trimmer is preset so that your voice level in the headphones will be
approximately ¾ of the intercom line level. To prevent feedback, this signal is automatically
turned off when the external speaker is turned on with the SPKR ON switch.
Speaker Dim Adjustment (R157)
When an external speaker is used, switching the microphone on will cause the speaker level to
attenuate. The level of attenuation may be adjusted with the speaker dim trimmer (R157). The
minimum attenuation of 6 dB is preset at the factory (R157 fully clockwise). The range of
adjustment is –6 dB to –40 dB.
Mechanical Installation
Dimensional requirements for the various mounting configurations are illustrated in Section 6.
Also allow an additional 4.0 inches (102 mm) of rear panel clearance for connectors.
If the headset connector is remotely located (See “External Headset”), allow space between the
cable and interfering sources such as TV monitors, power supplies and equipment with internal
power supplies. The MCE325 has no special ventilation space requirements.
Assembly of optional mounting components is shown in Figure 2.3.
2-6
MCE-325 User Instructions
Figure 2.3
Mounting configurations.
2-7
Electrical Installation
AC Power and Fuse
The Model MCE325 is pre-wired for either 115 or 230 VAC operation, and the appropriate fuse is
already installed. The MCE325 uses a 0.5A Slo-Blo fuse for 115 volt operation, or a 0.25A SloBlo fuse for 230 volt operation. (A fused external DC source may be used instead of AC power if
desired. (See “External DC Power Source”.)
Intercom Lines J8, J9, and J10
General
Intercom line connectors J8 and J9 are parallel-wired for loop-through connection to other
intercom stations. These connectors are used for connection of two-wire lines to channels one and
two (full-duplex operation), or for connection of four-wire channel A output (channel A input is
connected at the auxiliary connector).
Intercom line connector J10 is used for connection of two-wire lines to channels three and four
(full-duplex operation), or for connection of four-wire channel B output (channel B input is
connected at the auxiliary connector).
Connector Pin-outs
Table 2.4
Connectors J8 and J9.
PIN # FUNCTION
1
Common (low side of line)
2
Two-wire CH 1 or four-wire CH A high output
3
Two-wire CH 2 or four-wire CH A low output
Table 2.5
Connection J10
PIN # FUNCTION
1
Common (low side of line)
2
Two-wire CH 3 or four-wire CH B high output
3
Two-wire CH 4 or four-wire CH B low output
Four-wire Output Termination
Figure 2.4
4-wire output terminations.
When four-wire outputs are used, termination resistors must be installed for proper operation. The
output amplifiers are current sources, and the output level is determined by the terminating
2-8
MCE-325 User Instructions
resistor values. These resistors would normally be installed in the cable connector, but may be
placed at any point in the signal path. Recommended values are shown in Figure 2-4.
Program Inputs, J14 and J15
The PROGRAM A and B inputs accept line-level (0 dBu nominal), balanced audio. The program
inputs are connected using ¼-inch stereo phone plugs.
Figure 2.5
SECTION
Connectors J14 and J15.
FUNCTION
Tip
Program high
Ring
Program low
Sleeve
Common
The MCE325 must be internally programmed to assign the program inputs to the intercom lines,
headphones, or speaker output (see “Program Assignment”). Program volume to the headphones
and speaker is controlled by the PGM VOL control on the front panel.
External Speaker, J27
The SPEAKER OUTPUT jack provides a bridging-type output for an external speaker (8 ohms
minimum). The external speaker is connected using a ¼-inch phone plug.
Figure 2.6
SECTION
CAUTION
Connector J27.
FUNCTION
Tip
Speaker plus
Ring
Speaker minus
Sleeve
No connection
The MCE325 provides a bridging-type speaker output. DO NOT LET EITHER SPEAKER
LEAD CONTACT GROUND.
The external speaker is turned on and off by the front panel SPKR ON switch.
Auxiliary Connector, J22
Four-Wire Channel A and B Input
The four-wire channel A and channel B inputs are connected at the auxiliary connector as
follows:
Table 2.6
Auxiliary connector, J22.
PIN #
FUNCTION
8
Four-wire channel A high
21
Four-wire channel A low
9
Four-wire channel B high
22
Four-wire channel B low
The four-wire inputs must be assigned, using internal programming jumpers J19 and J20, before
they can be used (as previously described in “Intercom Line-Channel Configurations (DS1-DS3,
J6, J7, J19 & J20).”
2-9
Key outputs – Expanded IFB Option
Four logic-type outputs are available at pins 6, 7, 19, and 20 of the auxiliary connector:
Table 2.7
Auxiliary connector, J22.
PIN #
FUNCTION
6
CH 1 or four wire CH A key output
7
CH 3 or four-wire CH B key output
19
CH 2 key output
20
CH 4 key output
There are internal pull-up resistors on the CH 3 and CH 4 key outputs. Pressing the CH 3 or CH 4
talk button will result in a logic high to low transition at the corresponding key output. (Logic
high is approximately 13 VDC; Logic low is less than 2 VDC.) There are no internal pull-up
resistors on the CH 1 and CH 2 key outputs. These outputs will “float” until externally loaded.
The channel three and four key outputs may also be used to expand the IFB function, allowing
any one of several MCE325 User Stations to interrupt a single-point program source and talk on
the interrupted channel. For example, if one MCE325 is operating with PROGRAM A assigned to
channel three, the channel three key output of a second MCE325 User Station (with no program
connected) can be directly connected to the channel three key output of the first MCE325;
activating channel three for talk from either station will now interrupt the program source and
permit that station to talk on channel three.
Remote Microphone Switch
A remote microphone switch may be connected at the auxiliary connector. Connect mic switch
high to pin 24; connect mic switch low to pin 10 or 11. When the switch is closed, the microphone
will turn on, and the front panel MIC ON LED will illuminate. When the remote switch is off, the
microphone may be turned on from the front panel. When the remote switch is on however, the
microphone cannot be turned off from the front panel.
ISO Connection
To connect an RTS Model VCP6A, VCP12A, or VCP12B ISO Control Panel to the MCE325,
connect the unswitched microphone output of the MCE325 (pins 1 and 14 of the auxiliary
connector) to the four-wire input of the VCP Control Panel; connect the four-wire output of the
VCP Control Panel to either a four-wire input or a program input of the MCE325; connect the
logic contact output of the VCP Control Station to the ISO input of the MCE325 (pin 12 of the
auxiliary connector); connect VCP common to pin 11 of the auxiliary connector.
External Headset
An external headset may be connected to the auxiliary connector. (See “Headset Requirements”.)
Connect headphone left to pin 5, headphone right to pin 18, and headphone common to pin 17.
Connect microphone high to pin 4; connect microphone low to pin 16. The external headset
connections are wired in parallel with the front panel dynamic headset connector; therefore, use
only one at a time.
In the headset connecting cable, prevent coupling between the microphone and headphone leads
by using a shielded twisted pair for the microphone, and a separate shielded twisted pair for the
headphones. Do not allow headphone common to contact microphone low. Tie the headphone
shield to headphone common. The headset cable can be made longer when the microphone and
headphone pairs are physically separated. The wider the separation, the longer the allowable cable
length. Estimated maximum usable headphone cable lengths are as follows:
Single cable, two shielded twisted pairs: 10 feet (3.05 m). Dual-ribbed cable, two shielded twisted
pairs: 30 feet (9.14 m).
2-10
MCE-325 User Instructions
Separate shielded twisted pair cables: 50 feet (15.24 m). Balanced microphone input: up to 100
feet (30.48 m).
External Electret Microphone
An external electret microphone may be connected at the auxiliary connector and used in place of
a front-panel gooseneck microphone. Connect microphone high/bias to pin 15 and connect
microphone low to pin 2. When using an external microphone, do not connect a front-panel
gooseneck microphone.
Unswitched Microphone Output
The microphone audio is provided as an unswitched, balanced output at the auxiliary connector.
The in-phase signal is available at pin 1; the inverted-phase is available at pin 14.
External DC Power Source
The MCE325 may be powered from an external DC power supply in the 10 to 25 volt range (500
mA minimum).
If the external supply is in the 10 to 15 volt range, connect the positive lead to pin 13 of the
auxiliary connector and connect the minus lead to pin 10 or 11. A 0.5 Amp slo-blo fuse should be
connected in-line for 17 to 24 volt operation.
Remote Speaker Mute Control
When the MCE325 is used with an external speaker, the speaker may be muted from a remote
location. Applying a logic low signal to pin 25 of the auxiliary connector will cause muting.
Connect circuit common to pin 11.
Front Panel Headset Connections
Headset Requirements
Use headphones with an impedance of 25 ohms or greater. Low impedance 8 ohm headphones are
not recommended. Headphones with good acoustic isolation (20 to 40 dB) improve
communication in high ambient noise environments, and allow the user to use the headphones at a
less tiring, lower volume.
Headset Connections
Dynamic-microphone headset connector: XLR-6 type receptacle.
Table 2.8
Dynamic-microphone headset connector.
PIN #
FUNCTION
1
Balanced mic low/unbalanced mic common
2
Balanced/unbalanced mic high
3
Headphone/mic switch common
4
Headphone left
5
Headphone right
6
Mic Switch high
2-11
Carbon-microphone headset connector: ¼-inch, tip-ring-sleeve phone jack.
Table 2.9
Carbon-microphone headset connector.
SECTION FUNCTION
2-12
Tip
Carbon microphone
Ring
Headphone
Sleeve
Common/ground
MCE-325 User Instructions
S
E C T I O N
OPERATION
CHAPTER3
General
The front panel buttons have different functions when the MCE325 is switched from operating
mode to setup mode. Legends on the buttons indicate their operating mode functions; legends
under the buttons indicate their setup mode functions. All of the front panel buttons were preprogrammed for a certain type of operation. This is the default configuration. Operation for the
default configuration is described first, and is then followed by front panel programming
instructions to alter the operation.
Operating Instructions
Momentary/Latching Button action
NOTE
The channel selector buttons and the MIC ON button feature a special momentary/latching dualaction: if a button is pressed and released quickly it will “latch” (turning “on” if off or turning
“off” if on); if the button is pressed and held slightly longer, the action will be momentary and the
button will turn off when released. All other buttons are latching-only (press to activate, press to
release).
The latching action can be disabled through the front panel programming.
LED Indicators
LED indicators are provided for each button to indicate current status. The LED can provide up to
four indications: continuously off, continuously on, short blink (50% on, 50% off) and long blink
(90% on, 10% off).
Channel Selection
Table 3.1 summarizes the operation of the channel selector buttons for the various intercom line
configurations. Basically, four-wire intercom lines always use one TALK and one LISTEN
button for intercom communication, as do two-wire lines when the station has been programmed
for two-channel operation.
When the station is operated in four-channel mode, however, each two-wire intercom line uses
only one channel selector button to control both talk and listen, and the MCE325 is preprogrammed so that a channel is activated for both talk and listen when the button is pressed. The
3-1
button action can be changed, via the front panel programming, so that the button controls talk
only, with listen either always on or always off.
Panel Mic/Headset Mic Selection
The PANEL MIC button selects either panel microphone (LED on) or headset microphone (LED
off).
Microphone On/Off
NOTE
The MIC ON button turns the microphone on (LED on) or off (LED off).
The MCE325 can be programmed, via the front panel, so that the microphone will automatically
turn on whenever a channel is activated for talk. The MCE325 may also be internally
programmed for voice-activated microphone (VOX) as previously described in Section 2.
Speaker On/Off
The SPKR ON button turns the external speaker on (LED on) or off (LED off).
Volume Adjustment
NOTE
Table 3.1 summarizes the operation of the volume controls for the various intercom line
configurations. The MCE325 is pre-programmed for stereo operation; CH 1 (VOL 1) adjusts the
level to the left headphone and CH 2 (VOL 2) adjusts the level to the right.
The MCE325 can be programmed, via the front panel, for monaural operation if desired.
The PGM VOL control adjusts the monaural mix of both program inputs to both headphones and
to the external speaker. It does not affect the program volume on the intercom lines.
Front Panel Sidetone Nulling Trimmer Adjustment
When the MCE325 is used with two-wire lines, the station operator’s voice signal is not only
transmitted onto the intercom lines, but also echoed back into the MCE325 receive circuits. This
can result in acoustic feedback when the MCE325 is used with an external speaker. The sidetone
nulling trimmers are used to null, or subtract, the station operator’s voice signal from the rest of
the received signal to prevent this feedback. (NOTE: This is not necessary in four-wire systems
since transmit and receive use separate circuits.) A trimmer is provided for each of the four
channels. The trimmers are factory-preset for maximum nulling of the microphone signal when
an ideal 200-ohm resistance terminates each intercom channel; however, the trimmers may
require slight readjustment after the MCE325 has been installed to compensate for variations
from the ideal.
To adjust the sidetone nulling trimmers:
1 Turn the speaker switch on (even if an external speaker is not connected). This will turn off the
internal, true sidetone trimmer (see note below).
2 Turn on the microphone.
3 Activate one talk button at a time, and speak into the microphone. Slowly increase the volume,
NOTE
3-2
and note the level of your voice in the headphones or speaker. Adjust the corresponding
sidetone nulling trimmer to minimize your voice signal. Repeat for each channel being used,
making sure that only one channel is activated at a time.
There is also an internal, true sidetone trimmer, which allows the station operator to hear his or
her voice when using headphones. This sidetone signal is turned off when the speaker switch is
MCE-325 User Instructions
turned on to prevent feedback. See “Headphone Sidetone Trimmer Adjustment (R37)” for further
details.
Sending and Receiving Call Signals
To call a channel:
1 Press the CALL button; the CALL LED’s will flash to indicate “call signal ready”.
2 Press and hold the talk button for the channel to be called; the call signal will be transmitted as
long as the talk button is held.
3 When a response is received, release the talk button to turn off the call signal.
Receiving a call:
When there is an incoming call, the indicator LED above the appropriate channel selector button
will flash.
Using the Talk-Off Feature
The talk-off feature deactivates the mic switches of all remote user stations on a selected channel.
To use talk-off:
1 Press and release the CALL button three times in rapid succession; the CALL LED’s will turn
on to indicate “talk-off signal ready”.
2 Momentarily press the talk button for the channel to be deactivated. This will cause the talk-off
signal to be transmitted.
3 Release the talk button to end the talk-off signal transmission.
Front Panel Programming
Activating Setup Mode
Press and hold the CALL button for 5 seconds: the TALK 1, LISTEN 1, TALK 2, LISTEN 2,
PANEL MIC, SPKR ON, and MIC ON LED’s will begin to flash. This is the main menu.
Menu Selection/Ending Setup
NOTE
The submenu names are listed under the switches. Press the desired switch to access the submenu
for that switch. Press the CALL button from a submenu to return to the main menu; press the
CALL button again to exit from the main menu to the operating mode.
If no submenu is selected from the main menu within 12 seconds after program mode activation,
the programming mode will time out, and the MCE325 will return to normal operation. If a
submenu is selected, however, the unit will remain in programming mode until intentionally
exited.
Submenus
The following paragraphs describe each of the submenus. The default, or factory pre-programmed
setting, is also indicated for each submenu.
3-3
Channel ID
The MCE325 can be programmed so that when someone is talking on an intercom channel, the
corresponding listen button LED will flicker as they talk to provide a visual indication of which
channel is talking. With the Channel ID submenu selected, press each TALK button to select or
deselect Channel ID. The button’s LED will indicate the Selected mode as follows:
Short LED blink: Channel ID disabled. (default).
Long LED blink: Channel ID enabled.
Four-channel Listen
When the MCE325 is operating in four-channel mode, each channel selector button may be
individually programmed for one of three types of operation. With the Four-channel Listen
submenu activated, press each channel selector button one or more times to select the desired type
of operation as follows:
Short LED blink (50% on, 50% off): Button must be pressed to talk or listen (default).
Long LED blink (90% on, 10% off): Listen will always be on; button must be pressed to talk.
LED off: listen will always be off; button must be pressed to talk.
Mono
The headphone output may be configured for either monaural or stereo operation. With the Mono
submenu selected, press the Mono button one or more times to select the type of headphone
output as follows:
Short LED blink: (50% on, 50 % off): Stereo (default).
Long LED blink: (90% on, 10% off): Monaural.
Call Disable
Call disable prohibits incoming or outgoing call indication and signaling on selected channels.
With the Call Disable submenu selected, press each talk button to select the desired operation as
follows:
Short LED blink (50% on, 50% off): Call function enabled (default).
Long LED blink (90% on, 10% off): Call function disabled.
Button Lock
Button lock permits all buttons (except CALL) to be individually programmed for one of three
types of operation. With the Button Lock submenu selected, press each button one or more times
to select the desired type of operation as follows:
Short LED blink (50% on, 50% off): No button lock (default).
Long LED blink (90% on, 10% off): Button locked in the “on” position.
LED off: Button locked in the “off” position.
Latch Disable
Latch disable may be used to prohibit latching action for individual channel selector buttons and
the MIC ON button. With the Latch Disable submenu selected, press each channel selector button
or the MIC ON button one or more times to select the desired type of operation as follows:
Short LED blink (50% on, 50% off): Latching enabled (default).
3-4
MCE-325 User Instructions
Long LED blink (90% on, 10% off): Latching disabled.
Instant Mic
Talk buttons may be individually programmed to automatically activate the microphone when
pressed. With the Instant Mic submenu selected, press each talk button one or more times to select
the desired type of operation as follows:
Short LED blink (50% on, 50% off): Instant mic off (default).
Long LED blink (90% on, 10% off): Instant mic on.
Reset
To restore the original programming, hold down the CH 1 talk button for about two seconds while
powering up the MCE325.
Table 3.1
Front panel control usage for the various intercom line configurations.
VOLUME CONTROL USAGE CHANNEL SELECTOR BUTTON USAGE
CH 1 (VOL 1)
CH 2 (VOL 2)
1 TALK
1 LISTEN
2 TALK
2 LISTEN
CH 2 TALK
CH 2 LISTEN
CH 3 TALK &
LISTEN
CH 4 TALK &
LISTEN
CH B TALK
CH B LISTEN
CH B TALK
CH B LISTEN
CH A LISTEN
CH 3 TALK &
LISTEN
CH 4 TALK &
LISTEN
CH A LISTEN
CH B TALK
CH B LISTEN
Configuration 1: Two -2wire lines (CH 1 & CH 2). (Default configuration.)
CH 1
CH 2
CH 1 TALK
CH1 LISTEN
Configuration 2: Three or four 2-wire lines (CH 1, CH 2, CH 3, CH 4).
CH 1 & CH 3
CH 2 & CH4
CH 1 TALK &
LISTEN
CH 2 TALK &
LISTEN
Configuration 3: One 2-wire line (CH 1); One 4-wire line (CH B).
CH 1
CH B
CH 1 TALK
CH 1 LISTEN
Configuration 4: Two 2-wire lines (CH 1 & CH 2); One 4-wire line (CH B).
CH 1
CH 2 & CH B
CH 1 TALK &
LISTEN
CH 2 TALK &
LISTEN
Configuration 5: Two 2-wire lines (CH 3 & CH 4); One 4-wire line (CH A).
CH A & CH 3
CH 4
CH A TALK
Configuration 6: Two 4-wire lines (CH A & CH B).
CH A
CH B
CH A TALK
3-5
3-6
MCE-325 User Instructions
S
E C T I O N
MAINTENANCE
CHAPTER4
Preventive Maintenance
Clean the unit and verify its performance periodically.
Factory Support Information
Factory support information is located on the first page of this manual.
Corrective Maintenance
WARNING: Hazardous voltages exist inside the MCE325. Attempting diagnosis, repair,
or adjustment with the AC line connected could result in serious injury or death. These
servicing instructions are for qualified personnel only.
Access
1 Reference the AS6464 drawing in section 6. Remove the four long screws (item 4) and the two
short screws (item 5).
2 Lift off the top cover.
3 Pull the front panel slightly forward to clear the carbon mic jack on the main circuit board. Lift
NOTE
the front panel slightly while sliding the back panel toward the rear and out of the lower case.
The MCE325 may now be operated for troubleshooting.
when reassembling the bottom cover, make sure the rubber button on the inside of the bottom
cover (item 7) is toward the front of the unit.
Front Panel Removal
1 Unplug the panel mic (J1) and dynamic-mic headset (J2) connectors from the main circuit
board.
4-1
2 The ribbon connector from the front panel board to the main board is attached at both ends with
locking connectors. To unlock the connector, pull the outer shell away from the circuit board.
Then, pull the ribbon cable out.
Cleaning
Clean the front panel and case with alcohol or a mild solution of detergent and water, and then
wipe off detergent residue with a damp rag. Clean the circuit board (if necessary) with a
tetraflouroethane product such as Flux-Off® CZ by Chemtronics®. Use eye protection and avoid
breathing the vapors with these solvents. Also, avoid getting the solvent in any of the
potentiometers.
Test and Adjustment Procedures
Notes
• All AC voltages are RMS unless otherwise specified.
• All input and output levels were measured using an AC voltmeter calibrated for
1 mW = 0.775V at 600 ohms, but with the 600 ohms in the circuit (0 dBu).
• The following procedures involve changing the MCE325 programming. It may be useful to
note the current positions of all jumpers and DIP switches so that they can be returned to their
proper positions after testing.
• The inside of the top cover contains a location diagram for the programming jumpers and DIP
switches. Place it next to the MCE325 during testing for convenient reference.
• Test procedures are written to be performed in the order presented.
Test Equipment
• Variac
• 15 MHz Oscilloscope
• AC Voltmeter
• Frequency Counter
• DC Voltmeter
• Balanced Audio Generator
• 400 Hz to 30 kHz bandpass filter with +40 dB of gain
Power Supply Test
1 Set a variac to 117 VAC, 60 Hz, and connect the MCE325 to the variac. Observe that each
LED blinks on in sequence, and then all LED’s are off.
2 Measure the voltage across the secondary of T1 (between test points E7 and E8 on the main
circuit board).
Vsec = 18 ±1.8 VAC
3 Measure the DC voltage across the “+” and “-“terminals of bridge rectifier CR1.
VCR1 = 23 ±2.3 VDC
4-2
MCE-325 User Instructions
4 Measure the ripple.
Vripple = 140 mVp-p
5 Measure the regulated DC voltage at U26 pin 2. (There should be no ripple.)
VU26-2 = 13.85 ±0.3 VDC
6 Measure the mid-voltage source at U17 pin 7.
VU17-7 = 6.93 ±0.3 VDC
7 Measure the +5 V source at the output of U27 pin 2.
VU27-2 = 5.0 ±0.3 VDC
Initial Configuration
1 Set all internal jumpers and DIP switches as follows:
DIP Switches: Set all DIP switches, except DS3, to the default settings listed in Table 2.1. Set
DS3 to on. (This places the MCE325 in four-channel mode. Refer to Figure 1.11 for names of
buttons in standard four-channel mode.)
Jumpers: Set all jumpers, except J24, to the default settings listed in Table 2.2. Set J24 to the
balanced mic position (pins 1 and 2 shorted).
2 Connect a 200-ohm termination resistor across each of the four intercom channels:
CH 1: J8 pins 1 and 2
CH 2: J8 pins 1 and 3
CH 3: J10 pins 1 and 2
CH 4: J10 pins 1 and 3
3 Set all front panel buttons to off.
4 Set all volume controls to minimum.
Keying Output Test
1 Connect two 47 k ohm resistors: one from the key 1 output (J22 pin 6) to the +14 VDC supply;
NOTE
and one from the key 2 output (J22 pin 19) to the +14 VDC supply.
The cathode of D22 serves as a convenient connection point for the +14 VDC supply. (Refer to
the AS6245 drawing in Section 6 for the location of D22.) The key 1 and key 2 outputs require
external pull-up resistors. The key 3 and key 4 outputs have internal pull-up resistors (RP2B
and RP2D respectively) and do not require external pull-ups.
Figure 4.1
Auxiliary connector, J22.
4-3
2 Set the MIC ON button to on. Set all other front panel buttons to off.
3 Check for 13 VDC minimum at the key 1 output.
4 Turn CH 1 TALK on and check for less than 2 VDC at the key 1 output.
5 Repeat steps 3 and 4 for the other channels:
CH2 TALK: key 2 out (J22 pin 19)
CH3 TALK: key 3 out (J22 pin 7)
CH4 TALK: key 4 out (J22 pin 20)
6 Remove the 47 k ohm pull-up resistors when finished.
USMB (Un-Switched Microphone Balanced) Frequency Response
and Level Check
1 Set all front panel buttons to off.
2 Connect a signal generator to the DYN MIC HEADSET jack mic input (J2 pins 1 & 2).
3 Connect a 600 ohm resistor across the USMB output (J22, pins 1 and 14).
4 Connect an AC voltmeter across the 600 ohm resistor.
5 Verify the output levels for the input frequencies and levels in Table 4.2.
6 Remove the 600 ohm resistor across the USMB output.
Frequency Response and Level Check, Mic to Line
Four-Channel, Two-Wire Mode
1 Activate the MIC ON button. (All other front panel buttons should be off.)
2 Connect an AC voltmeter across the channel 1 output. The signal generator should still be
connected to the dynamic mic input.
3 Activate the CH 1 TALK button.
4 Verify the output levels for the input frequencies and levels in Table 4.3.
5 Repeat for channels 2 through 4 by connecting the AC voltmeter across the appropriate output,
activating the appropriate TALK button, and measuring the output level:
Table 4.1
Talk button vs. output.
TALK BUTTON
OUTPUT
CH 2
J8, pins 1 and 3
CH 3
J10, pins 1 and 2
CH 4
J10, pins 1 and 3
Table 4.2
USMB frequency response and level check.
INPUT
FREQUENCY INPUT LEVEL
4-4
OUTPUT LEVEL
1 kHz
-55 dBu (1.4 mV)
–45 dBu (4.35 mV)
–25 dBu (43.5 mV)
-1 ±3 dBu (0.49 – 0.98 VAC)
2.5 ±2 dBu (0.83 – 1.32 VAC)
2 ±2 dBu (0.75 – 1.2 VAC)
100 Hz
-55 dBu (1.4 mV)
–45 dBu (4.35 mV)
–25 dBu (43.5 mV)
-0.5 ±3 dBu (0.51 – 1.03 VAC)
4.2 ±2 dBu (0.98 – 1.55 VAC)
4.2 ±2 dBu (0.98 – 1.55 VAC)
MCE-325 User Instructions
Table 4.2
10 kHz
Table 4.3
USMB frequency response and level check.
-5.7 ±3 dBu (0.28 – 0.57 VAC)
2.2 ±2 dBu (0.79 – 1.26 VAC)
2.5 ±2dBu (0.83 – 1.32 VAC)
-55 dBu (1.4 mV)
–45 dBu (4.35 mV)
–25 dBu (43.5 mV)
Mic to line response; 4-channel, 2-wire mode.
INPUT
INPUT
FREQUENCY LEVEL
OUTPUT LEVEL
1 kHz
-0.8 ±2 dBu (0.56 – 0.89 VAC)
-45 dBu
100 Hz
-45 dBu
-0.8 ±2 dBu (0.56 – 0.89 VAC)
100 kHz
-45 dBu
0.8 ±2 dBu (0.56 – 0.89 VAC)
Two-Channel, Four-Wire Mode
1 Remove the 200 ohm terminations from intercom channels 1 through 4.
2 Program the MCE325 to be in two-channel, four-wire mode. (See Table 2.3, configuration 6
for switch settings. See Figure 1.11 for names of buttons in standard two-channel mode.)
3 Connect 200 ohm termination resistors across the four-wire A and four-wire B channels:
NOTE
Four-Wire A: J8 pins 2 and 3
Four-Wire B: J10 pins 2 and 3
Normally, the four-wire outputs would be terminated with 600 ohms for four-wire operation,
but 200 ohms are used for testing purposes.
4 Set the MIC ON button to on. Set all other front panel buttons to off.
5 Connect an AC voltmeter across the Four-Wire A output.
6 The signal generator should still be connected to the mic input. Set it to 1 kHz, -45 dBu.
7 Activate CH 1 TALK.
8 The output level should read –0.8 dBu ±2 dBu (0.56 – 0.89 VAC)
9 Connect the AC voltmeter across the Four-Wire B output.
10 Turn off CH 1 TALK and activate CH 2 TALK.
11 The output level should read –0.8 dBu ±2 dBu (0.56 – 0.89 VAC)
12 Remove the 200 ohm termination resistors.
Sidetone Null Test and Adjustment
NOTE
This procedure verifies sidetone null operation and optimizes nulling for an ideal 200 ohm line
termination. Since actual intercom line impedance may vary from the ideal, the MCE325 may
have to be readjusted slightly during actual use.
1 Reprogram the MCE325 to be in four-channel, two-wire mode (Table 2.3, configuration 2).
2 Reconnect 200 ohm termination resistors across each of the four intercom channels.
3 Set the MIC ON button to on. Set all other front panel buttons to off.
4 The signal generator should still be connected to the mic input. Set it to 1 kHz, -45 dBu.
5 Activate the CH 1 TALK button.
6 Monitor the AC signal level at U5 pin 7.
7 Adjust R57 (Sidetone 1 on front panel) for maximum null (minimum signal level) at U5 pin 7.
The signal should be 0.025 VAC or less.
4-5
8 Repeat for channels 2 through 4 by activating the TALK buttons, connecting to the test points
and adjusting the potentiometers as indicated in Table 4.4.
True Sidetone Adjust
1 Configure the DYN MIC HEADSET jack for stereo mode (See Section 3, “MONO”)
2 Set all front panel buttons to off.
3 Connect 51 ohm load resistors across the left headphone output (J2 pins 3 and 4) and right
headphone output (J2 pins 3 and 5).
4 Connect an AC voltmeter across the left headphone output.
5 Remove the signal generator from the mic input, and connect it across intercom channel 1.
Adjust the generator output to –1 dBu (0.69 VAC), 1 kHz.
6 Activate the CH 1 TALK button, and adjust the CH 1-3 volume control (R1) until you measure
11.2 dBu (2.82 VAC) across the left headphone output.
7 Disconnect the signal generator from intercom channel 1. Adjust the generator for minimum
output, and reconnect it across the DYN MIC HEADSET jack mic input (J2 pins 1 & 2).
Readjust the generator output level to –45 dBu, 1 kHz.
8 Turn on the MIC ON button.
9 Adjust R37 (sidetone) on the MCE325 main board to obtain 8.7 dBu (2.1 VAC) at the left
headphone output.
Level and Frequency Response Check, Intercom Channel to
Headphone
1 Set all front panel buttons to off.
2 Remove the signal generator from the mic input, and reconnect it across intercom channel 1.
3 Adjust the signal generator output to –1 dBu, 1 kHz.
4 Preset the CH 1-3 volume control to the 2 o’clock position.
5 Activate the CH 1 TALK button. The left headphone output level should be 11.2 ±2 dBu (2.2
to 3.6 VAC).
6 Adjust the CH 1-3 volume control to measure 11.2 dBu (2.8 VAC) at the left headphone
output. Check for no distortion or clipping in the output.
7 Adjust the signal generator output to –1 dBu, 100 Hz. The left headphone output should read
10.2 dBu ±2 dBu (1.9 to 3.2 VAC)
8 Adjust the signal generator output to –1 dBu, 10 kHz. The left headphone output should read
7.8 dBu ±2 dBu (1.5 to 2.4 VAC).
9 Repeat the test for channels 2 through 4. For channel 3, continue to use the CH 1-3 volume
control and monitor the left headphone output. For channels 2 and 4, use the CH2-4 volume
control and monitor the right headphone output.
Table 4.4
Channel 1-4 sidetone trimmer adjust.
TALK BUTTON TEST POINT POTENTIOMETER
4-6
CH 1
U5 pin 7
R57 (Sidetone 1)
CH 2
U5 pin 1
R73 (Sidetone 2)
CH 3
U7 pin 1
R88 (Sidetone 3)
CH 4
U7 pin 7
R104 (Sidetone 4)
MCE-325 User Instructions
Level and Frequency Response Check, Intercom Channel to Speaker
1 Set all front panel buttons to off. Set all volume controls to minimum.
2 Connect an 8 ohm load across the speaker output (J27, tip and ring)
3 Connect an AC voltmeter and an oscilloscope across the speaker output.
4 Connect the signal generator to intercom channel 1, and adjust the generator output to –1 dBu,
1 kHz.
5 Set the SPKR ON and CH 1 TALK buttons to on.
6 Rotate the CH 1-3 volume control (R1), and check that the speaker output level reaches +18
dBu (17.4 Vp-p) before clipping.
7 Set the CH 1-3 volume control to get +15 dBu (4.4 VAC) at the speaker output. The volume
control should be approximately at the 2 o’clock position.
8 Activate speaker muting by grounding J22 pin 25 to pin 10. The speaker output level should
drop to 5 mV or less, and the SPKR LED should turn off. Remove the ground connection.
9 Activate speaker dim by grounding U15 pin 9.
10 Adjust R157 to the maximum clockwise position. The speaker output should be –5.5dB ±1 dB
below the level set in step 7.
11 Adjust R157 to the maximum counter-clockwise position. The speaker output should be –39.5
dB ±2 dB below the reference level set in step 7.
12 Reset R157 to the maximum clockwise position, and remove the speaker dim ground (U15 pin
9).
13 Set the signal generator to –1 dBu, 100 Hz. The speaker output should be 10.8 dBu ±2 dBu.
14 Set the signal generator to –1 dBu, 10 kHz. The speaker output should be 17.5 dBu ±2 dBu.
Level and Frequency Response, Program to Headphones and
Speaker
Program A to Left Headphone
1 Set all front panel buttons to off. Set all volume controls to minimum.
2 Set program jumpers J16, J17 and J18 to assign PROGRAM A and PROGRAM B inputs to the
headphones and speaker (pins 1 & 2 shorted on all three jumpers).
3 Remove the signal generator from channel 1, and reconnect it to the PROGRAM A input (J14
tip and ring).
4 Set the signal generator to 0 dBu, 1 kHz.
5 Set the PGM VOL control to maximum.
6 Measure the level at the left headphone output. It should be 1.3 dBu ±2 dBu.
7 Set the signal generator to 0 dBu, 100 Hz. The left headphone output should be 0.8 dBu ±2
dBu.
8 Set the signal generator to 0 dBu, 10 kHz. The left headphone output should be –3.8 dBu ±2
dBu.
9 Reset the generator to 0 dBu, 1 kHz.
10 Remove jumper J16 (program not assigned to left headphone). Verify that the signal level
drops at least 35 dB from the reference level in step 9.
4-7
11 Restore jumper J16 to short pins 1 & 2.
Program B to Right Headphone
1 Remove the signal from the PROGRAM A input, and connect it to the PROGRAM B input.
2 Measure the level at the right headphone output (J2, 3 & 5). It should be 1.3 dBu ±2 dBu.
(Program volume at maximum.)
3 Set the signal generator to 0 dBu, 100 Hz. The right headphone output should be 0.8 dBu ±2
dBu.
4 Set the signal generator to 0 dBu, 10 kHz. The right headphone output should be –3.8 dBu ±2
dBu.
5 Reset the generator to 0 dBu, 1 kHz.
6 Remove jumper J17 (program not assigned to right headphone). Verify that the signal level
drops at least 35 dB from the reference level in step 2.
7 Restore jumper J17 to short pins 1 & 2.
Program to Speaker
1 Connect the AC voltmeter across the 8 ohm load at the speaker output
2 Set the SPKR ON button to the on position.
3 Measure the level at he speaker output. It should be 6 dBu ±2 dBu. (Program volume at
maximum.)
4 Set the signal generator to 0 dBu, 100 Hz. The speaker output should be 1.3 dBu ±2 dBu.
5 Set the signal generator to 0 dBu, 10 kHz. The speaker output should be 7.3 dBu ±2 dBu.
6 Reset the generator to 0 dBu, 1 kHz.
7 Remove jumper J18 (program not assigned to speaker). Verify that the signal level drops at
least 35 dB from the reference level in step 3.
8 Restore jumper J18 to short pins 1 & 2.
IFB Test
IFB B
1 Set all front panel buttons to off. Set all volume controls to minimum.
2 Move the J5 jumper to short pins 1 and 2 (IFB B assigned to channel 4).
3 Check the output level across intercom channel 4. It should be –9.8 dBu ±2 dBu.
4 Turn on the CH 4 TALK and MIC ON buttons. The channel 4 output should drop at least 45
dB from the reference level in step 3.
5 Turn off the CH 4 TALK and MIC ON buttons.
6 Ground the Key 4 input (short J22 pin 20 to pin 10). The channel 4 output should drop at least
45 dB from the reference level in step 3.
7 Remove the Key 4 ground.
8 Move the J5 jumper to short pins 2 and 3.
4-8
MCE-325 User Instructions
IFB A
1 Move the J4 jumper to short pins 1 and 2 (IFB A assigned to channel 3).
2 Remove the signal from PROGRAM B input, and connect it to the PROGRAM A input. Set
the signal generator to 0 dBu, 1 kHz.
3 Check the output level across intercom channel 3. It should be –9.8 dBu ±2 dBu.
4 Turn on the CH 3 TALK and MIC ON buttons. The channel 3 output should drop at least 45
dB from the reference level in step 3.
5 Turn off the CH 3 TALK and MIC ON buttons.
6 Ground the Key 3 input (short J22 pin 7 to pin 10). The channel 3 output should drop at least
45 dB from the reference level in step 3.
7 Remove the Key 3 ground.
8 Move the J4 jumper to short pins 2 and 3.
Level and Frequency Response Check, Four-Wire Input to
Headphone
Four-Wire A Input to Left Headphone
1 Set all front panel buttons to off. Set all volume controls to minimum.
2 Remove the signal generator from the Program A input, and connect it to the Four-Wire A
input (AUXILIARY connector J22, pins 8 and 21). Set the generator to 0 dBu, 1 kHz.
3 Move jumper J19 to short pins 3 & 4 (Four-Wire A input always on).
4 Set the CH 1-3 volume control to measure 0 dBu at the left headphone output. (The control
should be at about the 2 o’clock position.)
5 Set the signal generator to 0 dBu, 100 Hz. The left headphone output should be –0.9 dBu ±2
dBu.
6 Set the signal generator to 0 dBu, 10 kHz. The left headphone output should be –4.7 dBu ±2
dBu.
7 Move jumper J19 to short pins 2 & 3 (Four-Wire A input off).
Four-Wire B input to Right Headphone
1 Remove the signal from the Four-Wire A input, and connect it to the Four-Wire B input (J22,
pins 9 & 22).
2 Move jumper J20 to short pins 3 & 4 (Four-Wire B input always on).
3 Set the CH 2-4 volume control to measure 0 dBu at the right headphone output. (The control
should be at about the 2 o’clock position.)
4 Set the signal generator to 0 dBu, 100 Hz. The right headphone output should be –0.9 dBu ±2
dBu.
5 Set the signal generator to 0 dBu, 10 kHz. The right headphone output should be –4.7 dBu ±2
dBu.
6 Move jumper J20 to short pins 2 &3 (Four-Wire B input off).
4-9
Panel Mic to Channel Test
1 Turn all front panel buttons off. Set all volume controls to minimum.
2 Remove the signal from the Four-Wire B input and reconnect it to the panel mic input (J28 tip
and ring, it is easiest to connect to the back of the connector.).
3 Set the signal generator to –25 dBu, 1 kHz.
4 Turn on the CH 1 TALK, MIC ON and PANEL MIC buttons.
5 Check the channel 1 output. It should be –0.9 dBu ±2 dBu.
Carbon Mic to Channel Test
1 Turn off the PANEL MIC and MIC ON buttons. (Only the CH 1 TALK LED should be on.)
2 Connect a 470 ohm resistor across the CARBON MIC HEADSET jack (J3 tip and ring). The
MIC ON LED should turn on.
3 Remove the signal from the panel mic input, and reconnect it to the CARBON MIC
HEADSET jack.
4 Set the signal generator to 11.2 dBu, 1 kHz.
5 Check the channel 1 output. It should be –0.9 dBu ±2 dBu.
6 Remove the 470 ohm resistor from the carbon mic input.
VOX Test
1 Remove the signal from the CARBON MIC HEADSET jack, and reconnect it to the DYN
MIC HEADSET jack mic input (J2 pins 1 & 2).
2 Set the generator to –45 dBu, 1 kHz.
3 Set DIP switch DS8 to the on position (VOX enabled), and note that the MIC ON LED turns
on.
4 Adjust the signal generator output level to zero, and note that the MIC ON LED turns off.
5 Reset DS8 to off.
Mic Kill Receive Test
1 Set all buttons to off.
2 Remove the signal from the DYN MIC HEADSET jack mic input, and reconnect it to intercom
channel 1.
3 Adjust signal generator to –5 dBu, 24 kHz (check frequency with frequency counter).
4 Set the MIC ON button to on.
5 Activate the CH 1 TALK button. The MIC ON LED should turn off.
6 Attenuate the signal input by 20 dB. Try turning on the MIC ON button. It should not turn on.
7 Attenuate the signal an additional 10 dB. Try turning on the MIC ON button. It should turn on.
8 Adjust signal generator to –5 dBu at 22.320 kHz.
9 Try turning the MIC ON button on and off. It should turn on and off as usual.
10 Adjust the signal generator to –5 dBu at 23.520 kHz.
4-10
MCE-325 User Instructions
11 Try turning the MIC ON button on. It should not stay on.
12 Adjust signal generator to –5 dBu at 25.680 kHz.
13 Try turning the MIC ON button on and off. It should turn on and off as usual.
14 Adjust signal generator to –5 dBu at 24.480 kHz.
15 Try turning the MIC ON button on. It should not stay on.
16 Remove the signal generator from channel 1.
Mic Kill Transmit Test
1 Set all front panel buttons to off.
2 Connect a frequency counter an AC meter to the intercom channel 1 output.
3 Transmit a mic kill signal on intercom channel 1 (tap the CALL button 3 times, then press and
hold the CH 1 TALK key).
4 Check that the signal on the channel 1 output is between 23.7 to 23.9 kHz at –9.8 dBu ±2 dBu.
5 Release the CH 1 TALK button.
Call Transmit Test
1 Set all front panel buttons to off.
2 Transmit a call signal on intercom channel 1 (tap the CALL button, and while the call LED is
flashing, press and hold the CH 1 TALK key).
3 Check that the signal on the channel 1 output is between 19.9 to 20.1 kHz at –9.8 dBu ±2 dBu.
4 Release the CH 1 TALK button.
Call Receive Test
1 Set all buttons to off.
2 Reconnect the signal generator to intercom channel 1.
3 Adjust signal generator to –5 dBu, 20 kHz (check frequency with frequency counter).
4 Check that the CALL and CH 1 TALK LED’s are flashing.
5 Attenuate the signal input by 20 dB, and check that the LED’s are still flashing.
6 Attenuate the signal an additional 10 dB. The LED’s should stop flashing.
7 Adjust signal generator to –5 dBu, 18.600 kHz.
8 Verify that the LED’s do not flash.
9 Adjust signal generator to –5 dBu, 21.400 kHz.
10 Verify that the LED’s do not flash.
11 Adjust signal generator to –5 dBu, 19.600 kHz.
12 Verify that the LED’s do flash.
13 Adjust signal generator to –5 dBu, 20.400 kHz.
14 Verify that the LED’s do flash.
15 Remove the signal generator and frequency counter.
4-11
ISO Test
1 Set DIP switch DS3 to off (two-channel, two-wire mode).
2 Set DIP switch DS5 to on (talk muted during ISO).
3 Set all TALK and LISTEN buttons to on.
4 Connect a 100 ohm resistor from the ISO input (J22 pin 12) to circuit common (J22 pin 10).
Observe that the MIC ON LED turns on and the channel 1 and 2 TALK buttons turn off.
5 Remove the 100 ohm resistor across the ISO input.
6 Reset DIP switch DS3 to on and DS5 to off.
Remote Mic Switch Test
1 Set all buttons to off.
2 Connect a 100 ohm resistor from the remote mic switch input (J22 pin 25) to circuit common
(J22 pin 10), and observe that the MIC ON LED turns on.
3 Remove the 100 ohm resistor.
Program Lockout Test
1 Set DIP switch DS4 to on (front panel setup lockout enabled).
2 Press and hold the CALL button for ten seconds, and verify that the MCE325 does not enter
program mode.
3 Reset DS4 to off.
Noise Checks
1 Connect a 150 ohm load across the dynamic mic input (J2 pins 1 and 2).
2 Connect an 8 ohm load across the speaker output.
3 Connect 51 ohm loads across the left headphone output (J2 pins 3 & 4) and right headphone
output (J2 pins 3 &5).
4 Terminate each intercom channel into 200 ohms.
5 Set the MIC ON button to on.
6 Set the SPKR ON button to on.
7 Set all other front panel buttons to off.
8 Set all volume controls to minimum.
Note: Noise measurements in the following steps were made using a 30 kHz low pass filter
with +20 dB of gain inserted between the AC voltmeter and the MCE325.
9 Set the CH 1-3 volume control to maximum. Measure noise across the left headphone output. It
should measure -44 dBu or less.
10 Set the CH 1-3 volume control to minimum and set the CH 2-4 volume control to maximum.
Measure noise across the right headphone output. It should measure –44 dBu or less.
11 Set the CH 2-4 volume control to minimum. Measure noise across the speaker output. The
meter should read –44 dBu or less.
4-12
MCE-325 User Instructions
12 Turn on the SPKR ON button. The meter should read –38 dBu or less. Turn off the SPKR ON
NOTE
button.
Noise measurements in the following steps were made using a 400 Hz to 30 kHz bandpass
filter with +40 dB of gain.
13 Turn on the MIC ON switch. Measure noise at U1 pin 1 (mic preamp out). The voltmeter
should read –26 dBu or less.
14 Turn on the PANEL MIC button. The meter should read –37 dBu or less.
15 Turn all buttons off.
16 Measure noise at U12 pin 7 (program A preamp out). The voltmeter should read –51 dBu or
less.
17 Measure noise at U12 pin 1 (program B preamp out). The voltmeter should read –51 dBu or
less.
18 Measure noise across intercom channels 1 through 4. All should measure –50 dBu or less.
4-13
4-14
MCE-325 User Instructions
S
E C T I O N
PARTS LISTS
CHAPTER5
Packaging Assembly (9000-6464-00)
Table 5.1
Reference PD6464 Drawing, Section 6
Item No.
Description
RTS Part No.
1
User Manual, MCE325 User Station
9350-6464-00
2
Label, Warning
9170-6739-00
3
Final Assy, MCE325
9010-6464-00
4
Assy, 200-ohm Termination Plug
9020-6793-00
5
Keycap, Blank
2705-0020-00
Keycap, Printed (TALK 3)
9150-6643-09
Keycap, Printed (TALK 4)
9150-6643-10
Keycap, Printed (IFB 1)
9150-6643-11
Keycap, Printed (IFB 2)
9150-6643-12
Keycap, Printed (LISTEN 3)
9150-6643-13
Keycap, Printed (LISTEN 4)
9150-6643-14
Keycap, Printed (SSA 1)
9150-6643-15
6
Keycap, Printed (SSA 2)
9150-6643-16
Keycap, Printed (PAGE)
9150-6643-10
Keycap, Stem
4501-0064-00
Final Assembly, MCE325 (9010-6464-00)
Table 5.2
Item No.
Reference AS6464 Drawing, Section 6
Description
RTS Part No.
1
Front Panel Assy, MCE325
9020-6261-00
2
Back Panel Assy, MCE325
9020-6262-00
3
Case, MCE/MCS
9060-6260-00
4
MCE/MCS Case Screw
9160-6305-00
5
Screw, #4-40 x 1/4
1008-4081-00
6
Valox Film, 0.010” Thick
N/A
7
Rubber Stick-on Button
4501-5012-00
8
Label, Programming and FCC Notice 9170-6776-00
9
Lug, Solder, #16
1003-0003-00
5-1
Front Panel Assembly (9020-6261-00)
Table 5.3
Reference AS6261 Drawing, Section 6
Item No. Description
RTS Part No.
1
Bezel, MCE325
9070-6261-00
2
PC Board Assy, Front Panel, MCE325 9030-6246-00
3
Bushing Adapter
9110-6273-00
5
Keycap Stem
4501-0064-00
6
Knob, Channel Volume, MCE325
2703-0033-00
7
Knob, Program Volume, MCE325
2703-0034-00
8
Lightpipe, Button Indicator
4501-0061-00
9
Connector Insert, 6-pin Female (J2)
2018-0077-00
10
Plug, Panel Microphone
4501-0063-00
11
Lightpipe, Call Indicator
4501-0062-00
12
Screw, Thread Forming
51856-003
13
Connector Housing, 3-pin (P1)
59958-003
14
Phone Jack with Metal Bushing (J28) 2013-0048-00
15
Connector Housing, 6-pin (P2)
59958-006
16
Contact, Housing
59958-200
17
Flex Cable, 0.050” Centers
2515-0013-00
20
Keycap, Printed (TALK 1)
9150-6643-01
21
Keycap, Printed (LISTEN 1)
9150-6643-02
22
Keycap, Printed (TALK 2)
9150-6643-03
23
Keycap, Printed (LISTEN 2)
9150-6643-04
24
Keycap, Printed (CALL)
9150-6643-05
25
Keycap, Printed (PANEL MIC)
9150-6643-06
26
Keycap, Printed (SPKR ON)
9150-6643-07
27
Keycap, Printed (MIC ON)
9150-6643-08
5-2
MCE-325 User Instructions
Back Panel Assembly (9020-6262-00)
Reference AS6262 Drawing, Section 6
Table 5.4
Item No.
Description
RTS Part No.
1
PC Board Assy, Main
9030-6245-00
2
Heatsink Assy
9020-6324-00
3
Panel, Rear
9080-6262-00
4
Jack, Phone, 3 conductor, double closed circuit (J27) 2013-0003-00
5
Connector Housing (P23)
57767-203
6
cord, AC Power, Gray
2504-0004-00
7
Strain Relief, Flexible
2509-0025-00
8
Fuse, 0.5A, 250V Slo-blo
50547-015
9
Fuse Cap
57074-006
10
Fuse Holder body w/mtg Nut
2802-0003-00
11
Terminal, Wire Joint, Nylong
2017-0013-00
12
Screw, #4-40 x ¼
1008-4023-00
13
Nut, Hex Kep, #4-40
1007-0001-00
15
Nut, Hex Kep, #4-40
1007-0002-00
16
Lug, Solder, #16
51378-002
17
Shrink Tubing
LP
Heatsink Assembly (9020-6324-00)
Reference 9020-6324-00 Drawing, Section 6
Table 5.5
Item No.
Description
RTS Part No.
1
Heatsink, Model MCE325
9180-6324-01
2
IC LM4752T
511386000S
3
Adj. Regulatro, 3 Terminal, LM317T 53290000
4
Insulator
57896000
5
Washer, Nylon Shoulder
1006004000
6
Washer
50013035
7
Washer, Compression
1006004100
8
Screw PH, Cross
51845040
9
Thermal Compound
51741000
Main PC Board Assembly (9030-6245-01)
Table 5.6
Reference 9027-6245-01 Drawing, Section 6
Ref No.
Description
C1
Capacitor, EL, 100µF, 25V
RTS Part No.
51821524
C10
Capacitor, CM, 0.1µF, 50V
52676113
C100
Capacitor, Mylar, 1nF, 100V
1514R1022L
C101
Capacitor, CM, 0.1µF, 50V
52676113
C102
Capacitor, CM, 0.1µF, 50V
52676113
C103
Capacitor, EL, 10µF, 50V
51821110
5-3
Table 5.6
Reference 9027-6245-01 Drawing, Section 6
C104
Capacitor, CM, 0.1µF, 50V
52676113
C105
Capacitor, EL, 100µF, 25V
51821524
C106
Capacitor, EL, 4.7µf, 25V
51821621
C107
Capacitor, EL, 4.7µf, 25V
51821622
C108
Capacitor, EL, 100µF, 25V
51821524
C109
Capacitor, EL, 1000µF, 25V
51821526
C11
Capacitor, CM, 0.1µF, 50V
52676113
C110
Capacitor, CM, 0.1µF, 50V
52676113
C111
Capacitor, CM, 0.1µF, 50V
52676113
C112
Capacitor, EL, 220µF, 50V
52157534
C113
Capacitor, EL, 220µF, 50V
52157534
C115
Capacitor, CD, 10pF, 500V
52157502
C116
Capacitor, CD, 10pF, 500V
52157502
C117
Capacitor, CD, 10pF, 500V
52157502
C118
Capacitor, CM, 0.1µF, 50V
52676113
C119
Capacitor, Mylar, 0.01µF, 50V
52719007
C12
Capacitor, EL, 10µF, 50V
51821110
C120
Capacitor, CD, 100pF, 100V
1501R1011L
C121
Capacitor, CD, 10pF, 500V
52157502
C122
Capacitor, CM, 0.1µF, 50V
52676113
C125
Capacitor, EL, 4700µF, 35V
1513R4784G
C126
Capacitor, CD, 0.1µF, 500V
1510R1042Q
C127
Capacitor, EL, 10µF, 50V
51821110
C128
Capacitor, EL, 10µF, 50V
51821110
C129
Capacitor, EL, 100µF, 25V
51821524
C13
Capacitor, CM, 0.1µF, 50V
52676113
C130
Capacitor, CM, 0.1µF, 50V
52676113
C131
Capacitor, EL, 10µF, 50V
51821110
C132
Capacitor, CM, 0.1µF, 50V
52676113
C133
Capacitor, EL, 100µF, 25V
51821524
C134
Capacitor, CM, 0.1µF, 50V
52676113
C135
Capacitor, EL, 22µF, 50V
51821640
C136
Capacitor, CM, 0.1µF, 50V
52676113
C137
Capacitor, CM, 0.1µF, 50V
52676113
C138
Capacitor, CM, 0.1µF, 50V
52676113
C139
Capacitor, CM, 0.1µF, 50V
52676113
C14
Capacitor, EL, 100µF, 25V
51821524
C140
Capacitor, CM, 0.1µF, 50V
52676113
C141
Capacitor, CM, 0.1µF, 50V
52676113
C142
Capacitor, EL, 4.7µf, 25V
51821623
C143
Capacitor, EL, 4.7µf, 25V
51821624
C15
Capacitor, Mylar, 150pF, 100V
52157332
C16
Capacitor, CM, 0.1µF, 50V
52676113
C17
Capacitor, EL, 1µF, 50V
51821106
C18
Capacitor, CD, 100pF, 100V
1501R1011L
C19
Capacitor, CD, 100pF, 100V
1501R1011L
5-4
MCE-325 User Instructions
Table 5.6
Reference 9027-6245-01 Drawing, Section 6
C2
Capacitor, EL, 10µF, 50V
51821110
C20
Capacitor, CD, 100pF, 100V
1501R1011L
C21
Capacitor, CD, 100pF, 100V
1501R1011L
C22
Capacitor, CM, 0.1µF, 50V
52676113
C23
Capacitor, CD, 10pF, 500V
52157502
C24
Capacitor, CM, 0.1µF, 50V
52676113
C25
Capacitor, EL, 22µF, 50V
51821640
C26
Capacitor, EL, 47µF, 16V
51821068
C27
Capacitor, EL, 22µF, 50V
51821640
C28
Capacitor, CD, 100pF, 100V
1501R1011L
C29
Capacitor, CD, 100pF, 100V
1501R1011L
C3
Capacitor, EL, 100µF, 25V
51821524
C30
Capacitor, CD, 100pF, 100V
1501R1011L
C31
Capacitor, CD, 100pF, 100V
1501R1011L
C32
Capacitor, CM, 0.1µF, 50V
52676113
C33
Capacitor, CD, 10pF, 500V
52157502
C34
Capacitor, EL, 47µF, 16V
51821068
C35
Capacitor, EL, 22µF, 50V
51821640
C36
Capacitor, EL, 22µF, 50V
51821640
C37
Capacitor, CD, 100pF, 100V
1501R1011L
C38
Capacitor, CD, 100pF, 100V
1501R1011L
C39
Capacitor, CD, 100pF, 100V
1501R1011L
C4
Capacitor, CM, 1nF, 50V
52676101
C40
Capacitor, CD, 100pF, 100V
1501R1011L
C41
Capacitor, CM, 0.1µF, 50V
52676113
C42
Capacitor, CD, 10pF, 500V
52157502
C43
Capacitor, CM, 0.1µF, 50V
52676113
C44
Capacitor, EL, 22µF, 50V
51821640
C45
Capacitor, EL, 47µF, 16V
51821068
C46
Capacitor, EL, 22µF, 50V
51821640
C47
Capacitor, CD, 100pF, 100V
1501R1011L
C48
Capacitor, CD, 100pF, 100V
1501R1011L
C49
Capacitor, CD, 100pF, 100V
1501R1011L
C5
Capacitor, EL, 100µF, 25V
51821524
C50
Capacitor, CD, 100pF, 100V
1501R1011L
C51
Capacitor, CM, 0.1µF, 50V
52676113
C52
Capacitor, CD, 10pF, 500V
52157502
C53
Capacitor, EL, 22µF, 50V
51821640
C54
Capacitor, EL, 47µF, 16V
51821068
C55
Capacitor, EL, 22µF, 50V
51821640
C56
Capacitor, CM, 0.1µF, 50V
52676113
C57
Capacitor, EL, 22µF, 50V
51821640
C58
Capacitor, CM, 0.1µF, 50V
52676113
C59
Capacitor, CD, 100pF, 100V
1501R1011L
C6
Capacitor, CM, 1nF, 50V
52676101
C60
Capacitor, EL, 10µF, 50V
51821110
5-5
Table 5.6
Reference 9027-6245-01 Drawing, Section 6
C61
Capacitor, Mylar, 1nF, 100V
1514R1022L
C62
Capacitor, EL, 10µF, 50V
51821110
C63
Capacitor, CD, 100pF, 100V
1501R1011L
C64
Capacitor, Mylar, 1nF, 100V
1514R1022L
C65
Capacitor, CM, 0.1µF, 50V
52676113
C66
Capacitor, EL, 10µF, 50V
51821110
C67
Capacitor, Mylar, 1nF, 100V
1514R1022L
C68
Capacitor, EL, 10µF, 50V
51821110
C69
Capacitor, CD, 100pF, 100V
1501R1011L
C7
Capacitor, CM, 1nF, 50V
52676101
C70
Capacitor, Mylar, 1nF, 100V
1514R1022L
C71
Capacitor, EL, 10µF, 50V
51821110
C72
Capacitor, Mylar, 1nF, 100V
1514R1022L
C73
Capacitor, EL, 10µF, 50V
51821110
C74
Capacitor, CD, 100pF, 100V
1501R1011L
C75
Capacitor, Mylar, 1nF, 100V
1514R1022L
C76
Capacitor, CM, 0.1µF, 50V
52676113
C77
Capacitor, EL, 10µF, 50V
51821110
C78
Capacitor, EL, 10µF, 50V
51821110
C79
Capacitor, CD, 100pF, 100V
1501R1011L
C8
Capacitor, CM, 0.1µF, 50V
52676113
C80
Capacitor, Mylar, 1nF, 100V
1514R1022L
C81
Capacitor, Mylar, 1nF, 100V
1514R1022L
C82
Capacitor, EL, 1µF, 50V
51821106
C83
Capacitor, EL, 10µF, 50V
51821110
C84
Capacitor, CD, 100pF, 100V
1501R1011L
C84
500PF
52157018
C85
Capacitor, CM, 0.1µF, 50V
52676113
C86
Capacitor, EL, 10µF, 50V
51821110
C87
Capacitor, EL, 10µF, 50V
51821110
C88
Capacitor, CM, 0.1µF, 50V
52676113
C89
Capacitor, EL, 10µF, 50V
51821110
C9
Capacitor, CM, 0.1µF, 50V
52676113
C90
Capacitor, EL, 10µF, 50V
51821110
C91
Capacitor, CM, 0.1µF, 50V
52676113
C92
Capacitor, Mylar, 1nF, 100V
1514R1022L
C93
Capacitor, CM, 0.1µF, 50V
52676113
C94
Capacitor, CM, 0.1µF, 50V
52676113
C95
Capacitor, EL, 10µF, 50V
51821110
C96
Capacitor, CM, 0.1µF, 50V
52676113
C97
Capacitor, EL, 100µF, 25V
51821524
C98
Capacitor, CM, 0.1µF, 50V
52676113
C99
Capacitor, CM, 0.1µF, 50V
52676113
CR1
Bridge Rectifier, 4A, 50VRMS
1601097000
D1
Diode, 1N4004
50745005T
D10
Diode, 1N4004
50745005T
5-6
MCE-325 User Instructions
Table 5.6
Reference 9027-6245-01 Drawing, Section 6
D11
Diode, 1N4004
50745005T
D12
Diode, 1N4004
50745005T
D13
Diode, 1N4004
50745005T
D14
Diode, 1N914B
160109140B
D15
Diode, 1N914B
160109140B
D16
Diode, 1N914B
160109140B
D2
Diode, 1N914B
160109140B
D20
Diode, 1N4004
50745005T
D21
Diode, 1N4004
50745005T
D22
Diode, 1N4004
50745005T
D3
Diode, 1N914B
160109140B
D4
Diode, 1N914B
160109140B
D5
Diode, 1N914B
160109140B
D6
Diode, 1N4004
50745005T
D7
Diode, 1N4004
50745005T
D8
Diode, 1N4004
50745005T
D9
Diode, 1N4004
50745005T
FB1
#73 SHIELD BEAD
2404000100
FB2
#73 SHIELD BEAD
2404000100
FB3
#73 SHIELD BEAD
2404000100
FB4
#73 SHIELD BEAD
2404000100
J1
Connector, 3-pin
59958103
J10
Connector, Audio
59893001
J14
Jack, PC Mt., 3/8
2013004900
J15
Jack, PC Mt., 3/8
2013004900
J16
Header, 3-pin
2007009900
J17
Header, 3-pin
2007009900
J18
Header, 3-pin
2007009900
J19
Header, 4-pin
2007013400
J2
Connector, 6-pin
59958106
J20
Header, 4-pin
2007013400
J21
Connector
2006009600
J22
Connector, D-Sub, 25-pin
2004004000
J23
Header, 3-pin
2007011800
J24
Header, 3-pin
2007009900
J3
Jack, PC Mt., 3/8
2013004900
J4
Header, 3-pin
2007009900
J5
Header, 3-pin
2007009900
J6
Header, 3-pin
2007009900
J7
Header, 3-pin
2007009900
J8
Connector, Audio
59893001
J9
Connector, Audio
59892001
Q1
Transistor, 2N5087
1602508700
Q10
Transistor, 2N5460
1602546000
Q2
Transistor, 2N5210
1602521000
Q3
Transistor, 2N5484
1602548400
5-7
Table 5.6
Reference 9027-6245-01 Drawing, Section 6
Q4
Transistor, 2N5210
1602521000
Q5
Transistor, 2N5210
1602521000
R1
Resistor, CF, 1K Ohm, 5%, 1/8W
52154060
R10
Resistor, MF, 3.01K Ohm, 1%, 1/8W
54034301
R100
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R101
Resistor, CF, 10K Ohm, 5%, 1/8W
52154036
R104
Trimpot, 10K Ohm, Linear
1409006000
R105
Resistor, MF, 60.4K Ohm, 1%, 1/8W
54035604
R106
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R107
Resistor, MF, 60.4K Ohm, 1%, 1/8W
54035604
R108
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R109
Resistor, CF, 100 Ohm, 5%, 1/8W
52154084
R11
Resistor, CF, 620 Ohm, 5%, 1/8W
52154065
R110
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R117
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R118
Resistor, MF, 10K Ohm, 1%, 1/8W
54035100
R119
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R12
Resistor, CF, 1K Ohm, 5%, 1/8W
52154060
R120
Resistor, MF, 10K Ohm, 1%, 1/8W
54035100
R124
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R125
Resistor, MF, 10K Ohm, 1%, 1/8W
54035100
R126
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R127
Resistor, MF, 10K Ohm, 1%, 1/8W
54035100
R13
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R130
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R131
Resistor, MF, 10K Ohm, 1%, 1/8W
54035100
R132
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R133
Resistor, MF, 10K Ohm, 1%, 1/8W
54035100
R135
Resistor, CF, 10K Ohm, 5%, 1/8W
52154036
R138
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R139
Resistor, MF, 10K Ohm, 1%, 1/8W
54035100
R14
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R140
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R141
Resistor, MF, 10K Ohm, 1%, 1/8W
54035100
R142
Resistor, CF, 10K Ohm, 5%, 1/8W
52154036
R15
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R152
Resistor, CF, 200 Ohm, 5%, 1/8W
52154077
R153
Resistor, CF, 220K Ohm, 5%, 1/8W
52154004
R153
160K
52154007
R154
Resistor, CF, 47K Ohm, 5%, 1/8W
52154020
R155
Resistor, CF, 47K Ohm, 5%, 1/8W
52154020
R156
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R156
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R157
Trimpot, 20K Ohm, Linear
57148407
R16
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R17
Resistor, CF, 100 Ohm, 5%, 1/4W
52154305
5-8
MCE-325 User Instructions
Table 5.6
Reference 9027-6245-01 Drawing, Section 6
R170
Resistor, CF, 10K Ohm, 5%, 1/8W
52154036
R171
Resistor, CF, 10K Ohm, 5%, 1/8W
52154036
R172
Resistor, MF, 201 Ohm, 1%, 1/8W
54032301
R173
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R174
Resistor, MF, 201 Ohm, 1%, 1/8W
54032301
R175
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R176
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R177
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R178
Resistor, CF, 1M Ohm, 5%, 1/8W
52154988
R18
Resistor, CF, 100 Ohm, 5%, 1/4W
52154305
R180
Resistor, CF, 1K Ohm, 5%, 1/8W
52154060
R181
Resistor, CF, 2.7 Ohm, 5%, 1/8W
52154122
R182
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R183
Resistor, CF, 10 Ohm, 5%, 1/8W
52154108
R184
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R185
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R186
Resistor, CF, 1K Ohm, 5%, 1/8W
52154060
R187
Resistor, CF, 2.7 Ohm, 5%, 1/8W
52154122
R188
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R189
Resistor, CF, 10 Ohm, 5%, 1/8W
52154108
R19
Resistor, CF, 620 Ohm, 5%, 1/8W
52154065
R198
Resistor, CF, 270K Ohm, 5%, 1/8W
52154002
R199
Resistor, CF, 10K Ohm, 5%, 1/8W
52154036
R2
Resistor, Cf, 2K Ohm, 5%, 1/8W
52154053
R20
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R200
Resistor, CF, 2.2M Ohm, 5%, 1/8W
52154980
R201
Resistor, MF, 3.01K Ohm, 1%, 1/8W
54034301
R207
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R208
Resistor, CF, 10K Ohm, 5%, 1/8W
52154036
R209
Resistor, CF, 1K Ohm, 5%, 1/8W
52154060
R21
Resistor, CF, 47K Ohm, 5%, 1/8W
52154020
R211
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R212
Resistor, CF, 270K Ohm, 5%, 1/8W
52154002
R213
Resistor, CF, 270K Ohm, 5%, 1/8W
52154002
R214
Resistor, CF, 10K Ohm, 5%, 1/8W
52154036
R215
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R22
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R23
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R24
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R26
Resistor, CF, 5.1M Ohm, 5%, 1/8W
52154698
R261
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R262
Resistor, MF, 3.01K Ohm, 1%, 1/8W
54034301
R263
Resistor, MF, 201 Ohm, 1%, 1/8W
54032301
R264
Resistor, CF, 220K Ohm, 5%, 1/8W
52154004
R265
Resistor, CF, 220K Ohm, 5%, 1/8W
52154004
R266
Resistor, MF, 909 Ohm, 1%, 1/8W
54032909
5-9
Table 5.6
Reference 9027-6245-01 Drawing, Section 6
R267
Resistor, MF, 201 Ohm, 1%, 1/8W
54032301
R268
Resistor, CF, 200 Ohm, 5%, 1/8W
52154077
R269
Resistor, CF, 10K Ohm, 5%, 1/8W
52154036
R27
Resistor, CF, 200 Ohm, 5%, 1/8W
52154077
R28
Resistor, CF, 22K Ohm, 5%, 1/8W
52154010
R29
Resistor, CF, 5.1M Ohm, 5%, 1/8W
52154698
R3
Resistor, CF, 100 Ohm, 5%, 1/8W
52154084
R30
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R31
Resistor, CF, 5.1M Ohm, 5%, 1/8W
52154698
R32
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R33
Resistor, CF, 15K Ohm, 5%, 1/8W
52154032
R34
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R35
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R36
Resistor, CF, 10K Ohm, 5%, 1/8W
52154036
R37
Trimpot, 10K Ohm, w/knob
57148406
R38
Resistor, CF, 100 Ohm, 5%, 1/8W
52154084
R39
Resistor, Cf, 2K Ohm, 5%, 1/8W
52154053
R4
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R40
Resistor, CF, 30K Ohm, 5%, 1/8W
52154025
R41
Resistor, CF, 470K Ohm, 5%, 1/8W
52154996
R42
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R43
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R44
Resistor, CF, 2.7 Ohm, 5%, 1/8W
52154122
R45
Resistor, CF, 2.7 Ohm, 5%, 1/8W
52154122
R46
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R47
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R48
Resistor, CF, 10K Ohm, 5%, 1/8W
52154036
R49
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R5
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R50
Resistor, CF, 10K Ohm, 5%, 1/8W
52154036
R51
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R52
Resistor, CF, 47K Ohm, 5%, 1/8W
52154020
R53
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R54
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R55
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R57
Trimpot, 10K Ohm, Linear
1409006000
R58
Resistor, MF, 60.4K Ohm, 1%, 1/8W
54035604
R59
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R6
Resistor, CF, 1K Ohm, 5%, 1/8W
52154060
R60
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R61
Resistor, MF, 60.4K Ohm, 1%, 1/8W
54035604
R62
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R63
Resistor, CF, 100 Ohm, 5%, 1/8W
52154084
R64
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R65
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R66
Resistor, CF, 47K Ohm, 5%, 1/8W
52154020
5-10
MCE-325 User Instructions
Table 5.6
Reference 9027-6245-01 Drawing, Section 6
R67
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R68
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R69
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R7
Resistor, MF, 301 Ohm, 1%, 1/8W
54034150
R70
Resistor, CF, 10K Ohm, 5%, 1/8W
52154036
R73
Trimpot, 10K Ohm, Linear
1409006000
R74
Resistor, MF, 60.4K Ohm, 1%, 1/8W
54035604
R75
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R76
Resistor, MF, 60.4K Ohm, 1%, 1/8W
54035604
R77
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R78
Resistor, CF, 100 Ohm, 5%, 1/8W
52154084
R79
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R8
Resistor, MF, 301 Ohm, 1%, 1/8W
54034150
R80
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R81
Resistor, CF, 47K Ohm, 5%, 1/8W
52154020
R82
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R83
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R84
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R85
Resistor, CF, 10K Ohm, 5%, 1/8W
52154036
R88
Trimpot, 10K Ohm, Linear
1409006000
R89
Resistor, MF, 60.4K Ohm, 1%, 1/8W
54035604
R9
Resistor, MF, 301 Ohm, 1%, 1/8W
54034150
R90
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R91
Resistor, MF, 60.4K Ohm, 1%, 1/8W
54035604
R92
Resistor, MF, 20K Ohm, 1%, 1/8W
54035200
R94
Resistor, CF, 100 Ohm, 5%, 1/8W
52154084
R95
Resistor, CF, 100K Ohm, 5% 1/8W
52154012
R96
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R97
Resistor, CF, 47K Ohm, 5%, 1/8W
52154020
R98
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
R99
Resistor, CF, 22K Ohm, 5%, 1/8W
524154028
RP1
Resistor Network, 100K Ohm X4, No Common, 1.1W
1411100302
RP10
Resistor Network, 100K Ohm X4, No Common, 1.1W
1411100302
RP11
Resistor Network, 100K Ohm X4, No Common, 1.1W
1411100302
RP12
Resistor Network, 100K Ohm X4, No Common, 1.1W
1411100302
RP14
Resistor Network, 680 Ohm X 5, No Common, 1.5W
1411680000
RP15
Resistor Network, 680 Ohm X 5, No Common, 1.5W
1411680000
RP2
Resistor Network, 22K Ohm X 9, Pin 1 Common, 1.5W 1411220201
RP3
Resistor Network, 100K Ohm X4, No Common, 1.1W
RP5
Resistor Network, 22K Ohm X 9, Pin 1 Common, 1.5W 1411220201
RP6
Resistor Network, 10K Ohm X 4, Pin 1 Common, 0.9W 1411100204
RP7
Resistor Network, 10K Ohm X 4, Pin 1 Common, 0.9W 1411100204
RP8
Resistor Network, 22K Ohm X 9, Pin 1 Common, 1.5W 1411220201
RP9
Resistor Network, 22K Ohm X 9, Pin 1 Common, 1.5W 1411220201
1411100302
S1
Switch, DIP, Low Profile
1909000200
T1
R-Core XFMR
9020653400
5-11
Table 5.6
Reference 9027-6245-01 Drawing, Section 6
U1
IC, Dual Low-noise Op-Amp, NE5532N
53295000
U10
IC, Dual Low-noise Op-Amp, NE5532N
53295000
U11
IC, Dual Low-noise Op-Amp, TLO76
1603013500
U12
IC, Dual Low-noise Op-Amp, TLO77
1603013500
U13
IC, Analog Switch, CD4053BE
46638P1
U14
IC, Analog Switch, CD4053BE
46638P1
U15
IC, Analog Switch, CD4053BE
46638P1
U16
IC, Dual Low-noise Op-Amp, TLO78
1603013500
U17
IC, Dual Low-noise Op-Amp, NE5532N
53295000
U18
IC, Audio Amp, LM386
53281000
U19
IC, Audio Amp, LM387
53281000
U2
IC, Analog Switch, CD4053BE
46638P1
U20
IC, Reference, LM833
1603083300
U21
IC, Analog Switch, CD4053BE
46638P1
U22
IC, Undervoltage Sense, MC33064P-5
1603013700
U23
IC, UCN5821A
160358210A
U24
IC, UCN5821A
160358210A
U25
IC, UCN5821A
160358210A
U27
IC, Voltage Regulator, LM317
53290000
U28
IC, EEPROM, 1024 Bit, 93C56AN NA
1603013800
U29
Assy. Software, Version 1.6
9020634816
U3
IC, Analog Switch, CD4053BE
46638P1
U30
IC, Quad 2-input NAND, 4093B
160340930B
U4
IC, Analog Switch, CD4053BE
46638P1
U5
IC, Dual Low-noise Op-Amp, TLO72
1603013500
U6
IC, Dual Low-noise Op-Amp, TLO73
1603013500
U7
IC, Dual Low-noise Op-Amp, TLO74
1603013500
U8
IC, Dual Low-noise Op-Amp, TLO75
1603013500
U9
IC, Dual Low-noise Op-Amp, NE5532N
53295000
XJ16
Jumper
2515001001
XJ17
Jumper
2515001001
XJ18
Jumper
2515001001
XJ19
Jumper
2515001001
XJ20
Jumper
2515001001
XJ24
Jumper
2515001001
XJ4
Jumper
2515001001
XJ5
Jumper
2515001001
XJ6
Jumper
2515001001
XJ7
Jumper
2515001001
XU1
IC Socket, 8-Pin
53041002
XU29
IC Socket, 40-Pin
53041308
Crystal, 4MHz, 20pF
3301000700
Y1
5-12
WASHER FLAT
52186006
4-40X1/4
1008402300
4-40X3/8
1008403500
MCE-325 User Instructions
PC Board Assembly, Front Panel (9030-6246-00)
Table 5.7
Ref No.
R1-R3
DS9
Reference AS6246 Drawing, Section 6
Description
RTS Part No.
Pot, 10K Ohm, Audio
1406003901
LED, Super Bright, Red
1801001900
DS1-DS8 LED, Super Bright, Yellow 1801002200
S1-S8
J1
Keyswitch, No LED
1911004300
Connector
2006009600
5-13
5-14
MCE-325 User Instructions
S
E C T I O N
DIAGRAMS
CHAPTER6
3
12000 Portland Avenue South • Burnsville, MN • 55377
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