Mackie FR Series M.800 Service manual

Go To Bulletins

M•1400 / M•1400i / M•1200

SERVICE MANUAL

Version 1.2

Page 3 is interactive



1998 MACKIE DESIGNS, INC.

820-179-00

CAUTION

AVIS

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DO NOT OPEN

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NE PAS OUVRIR

CAUTION: TO REDUCE THE RISK OF

ELECTRIC SHOCK DO NOT REMOVE

THE COVER

NO USER SERVICEABLE PARTS INSIDE

REFER SERVICING TO QUALIFIED

PERSONNEL

WARNING: TO REDUCE THE RISK OF

FIRE OR ELECTRIC SHOCK, DO NOT

EXPOSE THIS PRODUCT TO RAIN OR

MOISTURE

TO PREVENT ELECTRIC SHOCK, DO

NOT USE THIS POLARIZED PLUG WITH

AN EXTENSION CORD, RECEPTACLE OR

OTHER OUTLET UNLESS THE BLADES

CAN BE FULLY INSERTED TO PREVENT

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The lightning flash with arrowhead symbol within an equilateral triangle is intended to alert the user to the presence of uninsulated "dangerous voltage" within the product's enclosure, that may be of sufficient magnitude to constitude a risk of electric shock to persons.

Le symbole éclair avec point de fléche à l'interieur d'un triangle équilatéral est utilisé pour alerter l'utilisateur de la présence à l'interieur du coffret de "vlotage dangereux" non isole d'ampleur suffisante pour constituer un risque d'éléctrocution.

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Le point d'exclamation à l'intérieur d'un triangle de la présence d'instructions importantes pour le fonctionnement et l'entretien (service) dans le livret d'instrucion accompagnant L'appareil.

®

TABLE OF CONTENTS

INTRODUCTION............................................................. 2

SYSTEM OVERVIEW ....................................................... 3

SUMMARY OF FEATURES .....................................................................4

SPECIFICATIONS...................................................................................6

CIRCUIT THEORY ........................................................... 8

INPUT CIRCUITRY..................................................................................8

POWER AMPLIFIER CIRCUITRY...........................................................8

PROTECTION CIRCUITS .......................................................................9

THERMAL MANAGEMENT..................................................................10

SERVICE PROCEDURES............................................... 11

REQUIRED EQUIPMENT LIST ..............................................................11

TROUBLESHOOTING TIPS - OUTPUT FAILURES ................................12

TEST AND BIASING PROCEDURE......................................................13

PARTS............................................................................ 15

QUICK PARTS ......................................................................................15

CHASSIS ASSEMBLY............................................................................16

HEATSINK ASSEMBLY..........................................................................18

COMPLETE PARTS LIST........................................................................20

SCHEMATICS / PCB LAYOUTS.................................... 23

INPUT PCB SCHEMATIC.....................................................................23

INPUT PCB LAYOUT ............................................................................24

DISPLAY PCB SCHEMATIC ................................................................25

DISPLAY PCB LAYOUT........................................................................26

MAIN PCB SCHEMATICS ...................................................................27

MAIN PCB LAYOUT ............................................................................30

SOFT START PCB SCHEMATIC ...........................................................31

SOFT START PCB LAYOUT...................................................................32

Click on any item to open that page

M•1200/M•1400 SERVICE MANUAL

INTRODUCTION

This manual contains complete service information for the M•1200, M•1400 and M•1400i audio power amplifiers. Operating instructions will be touched on briefly. For complete operating instructions refer to the owner’s manual.

The FR Series  M•1200 and M•1400 are high power audio amplifiers designed for professional applications. They feature audiophile quality sound, excellent stability, extensive protection circuitry, and legendary Mackie reliability. Patented Fast Recovery circuitry allows the M•1200/M•1400 to recover from clipping without generating undesirable artifacts.

SERVICE ON THE M•1200/M•1400 IS

TO BE PERFORMED BY EXPERIENCED

TECHNICIANS ONLY!

To service the M•1200/M•1400, technicians should be familiar with op-amps, discrete analog circuitry, and troubleshooting high power solid state amplifiers. Presentation of this manual does not constitute endorsement of qualifications by Mackie Designs.

! SMD !

The M•1200/M•1400 makes extensive use of surface mount components.

Servicing technicians should have the tools and experience to perform surface mount rework.

TECHNICAL SUPPORT

Mackie Designs Technical Support Department is available 8AM - 5PM PST, Monday -

Friday at 1-800-258-6883 (outside US call 011-425-487-4333) Please feel free to call with any questions (Better safe than sorry!).

DISCLAIMER

The information contained in this manual is proprietary to Mackie Designs, Inc. The entire manual is protected under copyright and may not be reproduced by any means without express written permission from Mackie Designs, Inc.

2 INTRODUCTION

VERSION 1.1

SYSTEM OVERVIEW

This section provides a quick summary of the M•1200/M•1400’s major features. It is not intended to take the place of the owner’s manual. It is included here to help servicing technicians familiarize themselves with the M•1200/M•1400.

DIFFERENCES BETWEEN THE M•1400, M•1400i AND M•1200

The M•1200 and M•1400 are electronically identical products with the following exceptions:

1. The M•1400 has 12,000uF main filter caps, where the M•1200 and M•1400i have

10,000uF.

2. The M•1400 and M•1400i use a more powerful fan than the M•1200.

3. The M•1400 has Speakon  connectors where the M•1200 and M•1400i have ¼” speaker outputs (both in addition to binding posts).

The M•1200 was discontinued in 1998 and replaced by the M•1400i.

Export M•1400’s also have a “Soft Start” circuit that is not installed on American units.

FAST RECOVERY DESIGN

Solid state power amplifiers have a reputation for sounding harsh when driven into clipping. The usual explanation is odd harmonics generated by hard clipping, but In fact much of the unpleasant sound is caused by latching and parasitic oscillations that occur as the amplifier recovers from clipping.

TYPICAL AMPLIFIER MACKIE FR SERIES 

ARTIFACTS CAUSED BY

LATCHING AND PARASITIC

OSCILLATION

Mackie’s Fast Recovery design recovers from clipping quickly without generating any undesirable artifacts. This performance is achieved by two unique design elements; the

Full Symmetry Dual Differential front end provides excellent linearity while minimizing the need for negative feedback, and the Baker Clamp prevents output/driver device saturation. How these circuits operate is covered in depth in the circuit theory section.

SYSTEM OVERVIEW 3

4


SUMMARY OF FEATURES

FRONT PANEL

1. GAIN

Detented gain controls adjust the level sent to each output section. The gain structure is designed so that a +4dBu (1.23V rms) input signal drives the amplifier to full rated power into 4 Ω.

2. METERS

The M•1200/M•1400’s meters indicate the relative output level of the amplifier referenced to full power. The SIG (signal present) senses the input prior to the gain control.

3. PROTECT

The Protect LEDs light indicating the channel has been muted for one of the following reasons:

•

4 second turn on delay

•

Output devices beyond Safe Operating Area (SOA), also lights SHORT LED(s).

•

Heatsink temperature beyond 80 degrees Celsius.

4. SHORT

The Short LEDs light to show that the amplifier has engaged protection due to a short or low impedance on the output.

5. TEMP STATUS

The HOT LED lights to indicate that the amplifier has engaged protection due to heatsink temperature or power transformer core temperature.

6. POWER SWITCH

This remarkable device requires years of study to full comprehend.

FULL SYMMETRY DUAL DIFFERENTIAL HIGH CURRENT DESIGN

CH

1

GAIN /dB

3v

20

18 22

1

4

1

6

8

2

4

2v

26

SENSITIVITY

28

30

1v

1.23v (+4dBu)

OL

- 3

- 6

- 9

- 2

0

SIG SIG

O

L

-3

-6

-9

- 2

0

1 2

GAIN /dB

3

16

1

8

0

2

2

24

2 v

14

8

3

0

1v

2

8

2

6

SENSITIVIT

Y

1.23v (+4dBu)

CH

2

1

CH

1

C H

2

INTERNALSTATUS

PROTECT

SHORT

TEMP STATUS

CH

1& 2

COL

D

HOT

3 4 5

PROFESSIONAL POWER AMPLIFIER

POWER

6

O N

OFF

SUMMARY OF FEATURES

VERSION 1.1

REAR PANEL

1. SPEAKER OUTPUTS

The M•1400 has Speakon  connectors where the M•1200 has ¼” speaker outputs. Both models have binding posts. For bridged mono operation, the + output comes from channel one’s positive terminal and - from channel two’s positive.

2. INPUT

The M•1200/M•1400 has both XLR and ¼” TRS inputs. They are electrically identical

(wired in parallel). In bridged mono or parallel mono mode channel 2 input is disabled.

3. THROUGH

Yet another jack wired in parallel with the Inputs, the through jack provides a convenient way to chain amplifiers or pass the signal to any other device.

4. LOW CUT FILTER

Sweeps the built in high pass filter from 10Hz to 170Hz.

5. CONSTANT DIRECTIVITY HORN EQ/AIR EQ

Built in shelving EQ provides high frequency compensation when using constant directivity horns.

6. AMP MODE

Three position slide switch selects STEREO, PARALLEL MONO or BRIDGE MONO operation.

Channel One’s input signal is used for PARALLEL MONO and BRIDGE MONO operation.

AMP MODE and OUTPUT APPLICATION switches should not be changed while the unit is on.

7. OUTPUT APPLICATION

Placing the three position slide switch in its center position defeats the built in LIMITER for both channels. Selecting SUB WOOFER engages the built in low pass filter. The

FREQUENCY switch selects between 125Hz and 63Hz cutoff for the low pass filter. In SUB

WOOFER mode, inputs 1 and 2 are summed regardless of AMP MODE setting.

(Remember, human hearing is unable to discern direction at frequencies where the wavelenth is greater than the distance between your ears, ~250Hz unless you have a grossly large head!)

(MONO BRIDGE)

1200 W A TTS

4 OHM LOAD MIN.

600 W A TTS CH

120 VAC 50/60 Hz

1500 WATTS

CAUTION

CH

1

+

-

+

MONO

BRIDGE

-

+

CH

2

-

SPEAKER OUTPUTS

1

4 2 6 2 4

1 CHANNEL

LOW CUT

FILTER

/ BRIDGE / MONO

TYPICAL

35 Hz

STAGE

MONITOR

100 Hz

OFF 170 Hz

INPUT

CONSTANT DIRECTIV ITY

HORN EQ/AIR EQ

4.5 kHz

2k Hz 6k Hz

OFF

TYPICAL

THRU

STEREO

TYPICAL

AMP MODE

MONO BRIDGE

OUTPUT APPLICATION

FULL

RANGE

LIMITER (CH1 & CH2)

STEREO

TYPICAL

SUB

WOOFER

FREQUENCY

125Hz

ON OFF 63Hz

THRU

INPUT

CHANNEL

LOW CUT

FILTER

BALANCED

O

STAGE

MONITOR

100 Hz

OFF 170 Hz

ON


HORN EQ /AIR EQ

4.5k Hz

2

OFF

TYPICAL

2k Hz 6k Hz

5 3 7 3 5

SYSTEM OVERVIEW 5

6


SPECIFICATIONS

CONTINUOUS AVERAGE OUTPUT

POWER, BOTH CHANNELS DRIVEN:

M•1200

225 watts per channel into 8 ohms from 20Hz to

20kHz, with no more than 0.025% THD





Bridged mono operation:

800 watts into 8 ohms from 20Hz to 20kHz, with no more than 0.050% THD


Maximum Power at 1% THD:

250

425

640

850

1280 watts per channel into 8 ohms watts per channel into 4 ohms watts per channel into 2 ohms watts into 8 ohms bridged watts into 4 ohms bridged

M•1400 / M•1400i







Bridged mono operation:



Maximum Power at 1% THD:

300

500

700

1000

1400 watts per channel into 8 ohms watts per channel into 4 ohms watts per channel into 2 ohms watts into 8 ohms bridged watts into 4 ohms bridged

Note : Power ratings are specified at

120VAC (U.S. and Canada) and 240VAC

(Export) line voltages.

The M•1200/M•1400 power amplifiers draw large amounts of current from the AC line with continuous sine wave testing. Accurate measurement of power requires a steady and stable AC supply. This means the line impedance must be very low to insure that the peak AC line voltage does not sag to less than

97% of its value.

If driving highly reactive loads, we recommend that the limiter circuit be engaged.

POWER BANDWIDTH:

20Hz to 70kHz (+0, –3 dB)

FREQUENCY RESPONSE:

20Hz to 40kHz (+0, –1 dB)

10Hz to 70kHz (+0, –3 dB)

DISTORTION:

THD, SMPTE IMD, TIM < 0.025% @ 8 Ω

< 0.050% @ 4 Ω

< 0.150% @ 2 Ω

SIGNAL-TO-NOISE RATIO:

> 107 dB below rated power into 4 ohms

CHANNEL SEPARATION:

> 80 dB @ 1kHz

DAMPING FACTOR:

350 minimum

INPUT IMPEDANCE:

20k balanced bridging

INPUT SENSITIVITY:

1.23 volts (+4 dBu) for rated power into 4 ohms

GAIN:

30.25 dB (32.5V/V)

MAXIMUM INPUT LEVEL:

9.75 volts (+22 dBu)

SPECIFICATIONS

VERSION 1.1

RISE TIME:

< 4.4µs

SLEW RATE:

Voltage Slew Rate

Current Slew Rate

CMRR:

> 40 dB, 20Hz to 20kHz

> 50V/µs

> 100V/µs bridged

> 32A/µs at 2 Ω

LOAD ANGLE:

8(±jx) time independent at 8 Ω

4(±jx) time dependent, T > 6 min. at 4 Ω

2(1±jx) time dependent, T > 2 min. at 2 Ω

TRANSIENT RECOVERY:

< 1µs for 20 dB overdrive @ 1kHz

HIGH FREQUENCY OVERLOAD AND

LATCHING:

No latch up at any frequency or level.

HIGH FREQUENCY STABILITY:

Unconditionally stable driving any reactive or capacitive load.

TURN ON DELAY:

3 seconds

VARIABLE LOW-CUT FILTER:

10Hz (Off) to 170Hz, 2nd Order Bessel

SUBWOOFER LOW-PASS FILTER:

Switched: 63Hz/125Hz, 3rd Order Bessel

CONSTANT DIRECTIVITY HIGH

FREQUENCY BOOST:

2kHz to 6kHz (+3 dB points)

6 dB/octave high-frequency shelving filter,

(shelving occurs at approximately 30kHz)

LIMITER SECTION:

Complementary Positive and Negative Peak

Detecting

INDICATORS:

6 meter LEDs per channel

SIG (Signal Present), –20, –9, –6, –3, OL

(Overload)

CH 1 & 2

PROTECT LEDs

SHORT LEDs

TEMP STATUS

COLD/HOT LEDs

POWER CONSUMPTION:

65 watts at idle

900 watts with musical program fully loaded

(2 ohms per side, or 4 ohms bridged)

550 watts with musical program fully loaded

(4 ohms per side, or 8 ohms bridged)

850 watts at full power into 8 ohms

(continuous sine wave)





AC LINE POWER:

US

Europe

Japan

Korea

120VAC, 60Hz

240VAC, 50/60Hz

100VAC, 50/60Hz

220VAC, 60Hz

AC DROP-OUT VOLTAGE:

At approximately 50% of rated line voltage

PHYSICAL:

Height

Width

Depth

Overall Depth

Handle Depth

Weight

3.5 inches

19.0 inches

15.25 inches

16.25 inches

1.25 inches

36 pounds

(89mm)

(483mm)

(387mm)

(413mm)

(32mm)

(16.3kg)

Since we are always striving to make our stuff better at Mackie Designs by incorporating new and improved materials, components, and manufacturing methods, we reserve the right to change these specifications at any time without notice.

SPECIFICATIONS 7

8


CIRCUIT THEORY

Much of the circuitry in the M•1200/M•1400 is self explanatory from the schematic. This section will explain the unique circuits and architecture. Samples in this section will refer to Channel 1 (Left) for circuitry that is identical on both channels.

INPUT CIRCUITRY

Refer to schematic on page 23.

The signal path begins with the INPUT BOARD. Following Channel 1’s input, signal is fed to a unity gain differential op-amp, U1A. The signal is next sent to U1B which serves as both HPF and CD horn EQ. If not in SUBWOOFER mode, the summing amp (U2B) and

LPF’s (U3A, U3B) are bypassed. The signal is sent via J11 to the gain control on the

DISPLAY BOARD. After the gain control, the signal is buffered by U7A, returned to the

INPUT BOARD and routed to the MAIN BOARD via J16.

Channel 2’s input signal path is electrically identical to Channel 1’s in STEREO mode. In

PARALLEL MONO mode Channel 2’s input signal is ignored and Channel 1’s input is sent to Channel 2’s gain control via SW5A. For BRIDGE MONO operation, Channel 1’s input signal is inverted by U2A and routed to the MAIN BOARD via SW5C.

POWER AMPLIFIER CIRCUITRY


The M•1200/M•1400 use a class AB triple darlington output with complementary output devices. The main power supply is +/- 80V, there is also a +/- 90V supply for the front end circuitry. Channels are muted for 4 seconds on power up as C53 charges via R203.

Muting is achieved by turning off Q73, removing current sources for the differential pairs.

(Wait a minute! PAIRS? Read on…)

An immediately obvious departure from standard designs is the Dual Differentials and

Symmetrical Voltage Amps. The reasoning behind this front end architecture is actually quite simple. Transistors transfer characteristics are not entirely linear, so even the best conventional front end design will introduce some distortion. Most amplifiers use negative feedback to reduce this problem (creating a few more in the process).

Mackie FR Series amplifiers take a different approach. By using two complementary

“mirror image” front end circuits any distortion caused by non-linear transistor curves is effectively canceled out in the bias string, without feedback!

Another design feature unique to Mackie FR Series Amplifiers is the Baker Clamp. The

Baker Clamp has two functions; 1) Prevent output/driver transistors saturating, 2) Drive the LIMITER LDR. Referring to the left main amp schematic, Q27 is a common base amplifier, it will turn on if Q31’s collector rises more than two diode drops above the

+80V supply, preventing it from rising further. There are three diode drops between

Q31’s collector and the base of driver transistor Q28 (D3, D2, Q29V be

). Q29 will never see a voltage greater than one diode drop below the +80V supply, even if the +80V supply fluctuates. Q27 also drives the limiter LDR LED U2A. The negative side has the same circuit mirrored.

CIRCUIT THEORY

VERSION 1.1

PROTECTION CIRCUITS

Refer to schematics on pages 27-29.

The M•1200/M•1400 has two output protection circuits in addition to the rail fuses. The first mutes the amp if the output devices are loaded beyond their safe operating area

(SOA). The second is a crowbar circuit that ensures the rail fuses blow if there is DC on the output.

SOA PROTECTION

The SOA protection circuit senses the voltage drop across the emitter resistors much like standard VI current limiting transistors. Q76 and Q77 will turn on if the emitter drop exceeds ~1V. If they are on for long enough to charge C38 (through R159), the SOA protection circuit is activated by transistor switches Q79 and Q78.

If SOA detection is tripped, the channel is muted by discharging C53 through R200 and

D65, fan speed is increased, and the “SHORT” LED lights.

DC CROWBARS

The DC Crowbar circuit protects speakers in the event of an output failure by blowing all rail fuses. SCRs Q21-24 are used to short the +/- 80V supply supplies to ground.

Output signal from both sides is fed through 100K resistors R90, R89 to C21, essentially forming a LPF. DC on either output will trigger comparator U4A (positive) or U4B

(negative). The SCRs are then fired via driver transistors Q87, Q88.

NOTE:

The LM339 comparator IC is used extensively in the

M•1200/M•1400. It differs from a standard op-amp used as a comparator in that it has an open collector output. If the voltage at the inverting input exceeds the non-inverting, the LM339’s output switches to it’s negative supply. Otherwise, the output is open.

CIRCUIT THEORY 9


THERMAL MANAGEMENT


The M•1200/M•1400 T-Design Heatsink/Fan cools output devices evenly and does not collect dust on the circuitry. The fan operates at two speeds, controlled by the amplifier. An LM35DZ mounted in the center of the heatsink provides temperature information to the fan control and overtemp circuits. There is also a thermal breaker in the power transformer.

FAN CONTROL CIRCUIT

The fan voltage comes from a feedback regulator circuit formed by Q91 and Q92. The output voltage is programmed by the ratio of R209 to R211// R207 (//=parallel). When the unit is powered up C83 charges through R241 providing a 40 second delay before the fan starts. As C83 charges, U6D’s output switches to -16V, starting the fan. Then

U6A’s output switches to open, allowing U6B to increase the fan speed, if triggered. R240 and C82 give the fan extra voltage when starting.

The fan speed is increased by U6B adding R211 in parallel with R207. (Q91 wants it’s base a diode drop above ground, so Q92 doubles its Emitter voltage). U6B is triggered by U4D to increase fan speed if;

•

Channel 1 SOA protection is activated (U5C),

OR

•

Channel 2 SOA protection is activated (U5D), OR

•

The heatsink is above 60 deg C (U5B) AND program is detected (U4C), OR

•

The heatsink temperature is above 80 deg C (U5A).

U6C and Q89 are used to reset the circuit on power down. Under normal operation

C50 is charged via D57, Holding Q89 off. When power is removed C50 discharges and

Q89 switches on as the rails collapse. When the voltage on Q89’s collector falls below ground U6 switches to the negative rail discharging C82 and C83.

THERMAL SHUTDOWN

Extreme heatsink or transformer core temperature will activate OVERTEMP. U5A activates overtemp if the LM35DZ detects heatsink temperature above 80 deg C.

Feedback resistor R137 rescales U5A’s voltage reference so that the heatsink must cool to below 50 deg C before overtemp is deactivated. Overtemp can also be activated by the power transformer thermal breaker (via Q89). In either case, both channel are muted via D69 and D66.

10 CIRCUIT THEORY

VERSION 1.1

SERVICE PROCEDURES

MECHANICAL PROCEDURES

The M•1200/M•1400 design allows easy removal of all components and assemblies.

Disassembly and reassembly should be self evident. This manual has exploded diagrams in the parts section.

Several important points concerning the assembly:

•

4 of the screws that secure the top cover also hold the front extrusion (curved piece) in place. When removing the top cover, be careful that the front extrusion is not dropped.

•

If the MAIN PCB is removed, be sure the smaller head machine screws (750-050-04) are replaced next to the filter caps. The larger head machine screws can arc to the capacitor body.

•

Be sure all tywraps are replaced and that no wires are in danger of being pinched in-between the cover and heatsink.

REQUIRED EQUIPMENT LIST

•

30 MHz dual trace oscilloscope

•

DMM (Must be capable of measuring 8mV DC with a minimum of 2 digits of accuracy, and down to .1

Ω )

•

Sine wave oscillator / Function generator (20Hz - 20KHz)

•

4 load resistors (8

Ω with a minimum 500W power rating)

•

10A / 120V Variac With AC voltmeter and a defeatable ammeter (1 Amp full range) or wattmeter (300 Watts full range)

•

0.1uF 400V film capacitor installed across dual banana plug

•

16 AWG shorting jumper installed across dual banana plug

RECOMMENDED EQUIPMENT LIST (PERFORMANCE VERIFICATION)

•

Distortion analyzer and low distortion oscillator.

(Capable of resolving distortion as low as 0.002% from 20Hz to 20KHz)

•

2500W AC power source.

SERVICE PROCEDURES 11


TROUBLESHOOTING TIPS - OUTPUT FAILURES

After a catastrophic failure, it is likely that the four +/-80V supply fuses will be blown.

Replace fuses and very slowly bring up the Variac while monitoring line consumption. It is likely that substantial line current will be pulled due to shorted output parts. At the same time, look for DC offset at the output. Offset of greater than +/- 2.8V will trigger the protection circuits and re-blow the four fuses. Keep the output offset below +/- 2V, or temporarily defeat the DC-offset detector (Lift one side of D56).

Remove the main board from the unit and check for shorted output transistors. If one bad output is found, replace all eight in the channel. When an output device shorts it can place high current stresses on the other output parts. These output parts can fail over time. Since long term reliability is paramount, please replace all the outputs.

All eight of the 3W 0.22

Ω emitter resistors must be verified for proper value. Any offtolerance, or open parts, need to be replaced. An off tolerance (higher resistance) emitter resistor will prevent it’s related output transistor from “doing it’s share” and will place more stress on it’s mates in the output section. Also verify the 8 base drive resistors

(2.2

Ω , 1/4W, fusible) are all OK. Verify that the drivers and pre-drivers are not shorted. If one driver is shorted replace it’s mate. Do the same with the pre-drivers. Also check all the resistors surrounding the drivers and pre-drivers.

Check the VI limiters and detectors. It is not uncommon to damage these parts when the amplifier fails in a spectacular way! Look for shorts on Q76, Q77, Q94, Q95, Q83,

Q84, Q96, and Q97. Verify proper value on the resistors that go to the bases of these devices. It is critical that these sections are working correctly. Shorted transistors can cause some odd asymmetrical clipping problems. Open parts will not allow the current limiting to operate effectively. If problems exist in these sections the amplifier might fail into a short, or might clip prematurely when loaded to 2 Ω .

All of the above trouble shooting (Not including part replacement) takes perhaps 15 to

30 minutes to do. If you take the time, and do all that is indicated above, it will allow

99% of the amplifiers to come up the first time! Trying to hurry, and skipping what is suggested, can lead to a frustrating and time consuming repair.

Slowly bring up the supply and verify that line consumption isn’t excessive and that the output is centered (no DC offset). It might be desirable to defeat the amplifier muting

(Connect U5-12, 13, & 14 together) temporarily so the amplifiers are active even when the supplies are still very low. If the amp stays centered, verify that it will pass a nice clean sine wave. Remove any test jumpers (I.E. DC-fault defeat & muting defeat) and proceed to the “Reliability Verification” section.

12 SERVICE PROCEDURES

VERSION 1.1

BIAS AND TEST PROCEDURE

After the unit has been repaired, the following should be done to assure long term reliable operation. If a distortion analyzer is present, distortion specifications should be verified.

1. Adjusts bias in both channels (R1 & R51) for 8mV +/- 0.3mV at bias test points (J53 &

J54) after unit has idled for a few minutes. With Full AC line voltage applied to unit, it will pull around 65W from the line (900mA at 120V). Measure for DC offset on both output connectors. DC offset should be less than +/- 50mV.

2. Apply a 1KHz sine wave to the inputs and verify that the unloaded outputs have a waveform that is symmetrical and undistorted. Drive the outputs into clipping and verify symmetrical “flat-topping” on the waveform.

3. Reduce output levels, install the 0.1uF capacitor jumper from the output to ground connections, and verify that clipping behavior is proper. Verify that no high frequency oscillation occurs near and at clipping (parasitic oscillation).

4. Remove capacitive loading and minimize sine output. Verify and re-adjust bias if required. Note that the bias will not drift appreciably in a unit that is functioning properly.

5. Connect the amplifier directly to the AC line and connect an 8 Ω dummy load to both channels. Bring sine wave level up on both channels and verify symmetrical clipping. The output will clip somewhere between 120V - 140V pk/pk depending on how stiff the line is. Clipping should be as described above. Add the 0.1uF

capacitive loading and verify clipping is still well behaved.

6. Individually load Channel 1 and Channel 2 with 2 Ω . Clipping should be symmetrical, well behaved , and occur somewhere around 80V - 100V pk/pk. Verify that clipping is well behaved after adding the 0.1uF capacitive loading.

7. Reduce output level to 20V pk/pk and short first channel one and then channel two. The front panel “short” and “protect” LEDs should flash on the respective channels.

8. Place amplifier in bridge mode and connect 4 Ω loading to bridge outputs (across both “+” output binding posts). Slip some card stock between the heatsink-outlets and chassis sides. Monitor one of the outputs and adjust for a 20V pk/pk signal.

Short across both outputs and verify that all four ‘Short” and “Protect” LEDs light and the amplifier mutes.

9. Remove short, monitor one of the outputs, and adjust for a 60V pk/pk sine output

(450W of output power bridged). After a few minutes the fan will begin running fast

(heatsink at 60 ° C) and a short time later the amplifier will mute (heatsink at 80 ° C).

The “Hot” and “protect” LEDs will come on. Remove card stock and after a few minutes the amplifier will come out of mute mode and the “cold” LED will return.

10. Disconnect loading and remove drive. Reconnect amplifier to Variac and confirm that the idle consumption is roughly 65W or 900mA, as before. Connect the amplifier to speakers and verify that it sounds OK with music.

SERVICE PROCEDURES 13


(THIS PAGE UNINTENTIONALLY LEFT BLANK), THOSE RESPONSIBLE HAVE BEEN PUT TO THE SWORD

14 SERVICE PROCEDURES

VERSION 1.1

PARTS

QUICK PARTS

FRONT PANEL

FULL SYMMETRY DUAL DIFFERENTIAL HIGH CURRENT DESIGN PROFESSIONAL POWER AMPLIFIER

CH

1

GAIN /dB

3v

20

18 22

1

4

1

6

8

2

4

2v

26

SENSITIVITY

28

30

1v

1.23v (+4dBu)

OL

- 3

- 6

- 9

- 2

0

SIG SIG

O

L

-3

-6

-9

- 2

0

GAIN /dB

3

16

1

8

0

2

2

24

2 v

14

8

3

0

1v

2

8

2

6

SENSITIVIT

Y

1.23v (+4dBu)

CH

2

HANDLE ASSEMBLYS

RIGHT, 080-023-10

LEFT, 080-023-20

SCREW(TO CHASSIS),700-028-04

CH

1

C H

2

INTERNALSTATUS

PROTECT

SHORT

TEMP STATUS

CH

1& 2

COL

D

HOT

GAIN CONTROLS

5KL POT, 130-036-00

KNOB, 760-061-00

NUT, 705-013-00

STAR WASHER, 710-023-00

ALL LEDS

RED T-1, 304-001-00

GREEN T-1, 304-004-00

POWER

O N

OFF

POWER SWITCH

500-022-00

REAR PANEL

(MONO BRIDGE)

1200 W A TTS

4 OHM LOAD MIN.

600 W A TTS CH

120 VAC 50/60 Hz

1500 WATTS

CAUTION

CH

1

+

-

+

MONO

BRIDGE -

+

CH

2

-

SPEAKER OUTPUTS

1 CHANNEL

LOW CUT

FILTER

/ BRIDGE / MONO

TYPICAL

35 Hz

STAGE

MONITOR

BALANCED

O

INPUT

OFF

170 Hz

100 Hz


HORN EQ/AIR EQ

4.5 kHz

2k Hz 6k Hz

OFF

TYPICAL

THRU

STEREO

TYPICAL

AMP MODE

MONO BRIDGE

OUTPUT APPLICATION

FULL

RANGE

LIMITER (CH1 & CH2)

STEREO

TYPICAL

SUB

WOOFER

FREQUENCY

125Hz

ON OFF

63Hz

THRU

INPUT

CHANNEL

LOW CUT

FILTER

BALANCED

O

R

STAGE

MONITOR

100 Hz

OFF 170 Hz

ON


HORN EQ /AIR EQ

4.5k Hz

2

OFF

TYPICAL

2k Hz 6k Hz

AC LINE CORD

US, 640-006-00

EUROPE, 640-007-01

JAPAN, 640-007-02

ENGLAND, 640-007-03

ITALY, 640-007-04

AUSTRALIA, 640-007-05

SWITZERLAND, 640-007-06

STRAIN RELIEF

740-004-00

INTERNAL FUSES

RAIL FUSES;

10A 5X20MM, 510-021-00

MAIN FUSE;

20A, 510-017-00

8A, 510-023-00

SPEAKER OUTPUTS

BINDING POSTS, 400-119-00

BINDING POST SCREW, 700-011-00

M•1200/M•1400i

¼” JACK, 400-118-00

WASHER, 710-019-00

SLOTTED NUT, 705-015-00

M•1400

SPEAKON , 400-138-00

SCREW, 700-055-00

INPUT SECTION

ALL KNOBS, 760-048-04

LOW CUT, 50KZx2 POT, 130-017-02

CD HORN EQ, 10KC POT, 130-037-02

¼” INPUT JACK, 400-214-00

¼” JACK WASHER, 710-002-00

¼” JACK NUT, 705-003-00

MALE XLR JACK, 400-142-00

FEMALE XLR JACK, 400-141-00

XLR JACK SCREWS,700-055-00

DP3T SWITCHES, 500-023-00

DPDT SWITCHES, 500-024-00

PARTS 15


CHASSIS ASSEMBLY

1 2

3

16 17 18

4

1 7

10

9

11

5

12

6

1

8

13

14

15

16 PARTS

VERSION 1.1

CHASSIS ASSEMBLY PARTS LIST

ITEM #

1

6

7

4

5

2

3

4

10

11

8

9

9

PART #

700-028-02

550-221-00

700-041-04

551-029-00

551-029-10

700-041-04

550-277-00

550-223-20

550-223-10

550-222-00

550-244-00

080-023-20

080-023-10

700-028-04

700-041-04

DESCRIPTION

SEMS 6-32X3/8 PHP BLKZC

TOP COVER - M1200

MCH 6-32X3/8 FL 100DG BLK

EXTR SCRN DSPLY BZL-M1200



SCREEN MANIFOLD - M1400

SIDE RAIL LEFT - M1200

SIDE RAIL RIGHT - M1200

BTM COVER - M1200

BOTTOM COVER - M1400

PNT HANDLE ASSY LEFT

PNT HANDLE ASSY RIGHT



12

13

14

15

16

17

18

TRANSFORMER / MOUNTING

600-016-00 XFMR M1200 120V

600-016-01

600-016-02

XFMR M1200 230V

XFMR M1200 100V

705-019-00

710-017-00

710-024-00

550-249-00

780-111-00

700-059-00

NUT HEX 5/16-18

WASH SPLTLCK 5/16 HEAVY

WASH FLAT 5/16 HARD (USS)

PLATE XFMR MTG - M1200

RUBBER PAD

HEX 5/16-18X3IN GD-5

550-247-00

780-042-00

055-079-00

700-028-02

760-048-04

550-275-00

710-002-00

705-003-00

700-055-00

SHIELD INPUT - M1200

INSUL MYLAR INPUT SHIELD

PCB ASSY INPUT 1200/1400


KNOB 9MM DARK GRAY

SPACER PLATE - AMPLIFIER

WASHER FOR ¼” JACKS

NUT FOR ¼” JACKS

MCH 4-24X3/8 PHP BLK HILO

055-080-00

055-081-00

080-072-01

080-072-02

700-028-02

700-050-04

700-011-00

710-019-00

705-015-00

700-055-00

PCB ASSY DISPLY 1200/1400

PCB ASSY MAIN - 1200

PCB ASSY MAIN - M1400

PCB ASSY MAIN - M1400i


MCH 6-32X3/8 FIL PHL CLR

MCH 4-40X1/4 BTNSKT BLKOX

WASH FIBRE BLK (W/JACK)

NUT SLOT NCKL


PARTS

NOTES

ALL SIDE PANEL SCREWS

TOP COVER TO CHASSIS

MANIFOLD TO FAN

HANDLE ASSY TO CHASSIS

HEATSINK TO CHASSIS BOTTTOM

INPUT PCB TO SHIELD

XLR JACK SCREWS

MAIN PCB TO CHASSIS EXCEPT FOR:

! USE THESE NEXT TO CAPS !

OUPTUT TERMINALS TO CHASSIS

17

HEATSINK ASSEMBLY


18 PARTS

VERSION 1.1

HEATSINK ASSEMBLY PARTS LIST

ITEM #

1

PART #

551-032-00

DESCRIPTION

EXTR FAB HEATSINK - M1200

410-003-00

055-081-00

080-072-01

080-072-02

550-255-00

700-058-02

710-020-00

710-022-00

550-224-00

410-003-00

700-010-00

710-013-00

700-010-04

550-237-00

700-028-02

550-225-00

700-010-00

770-006-00

770-007-00

550-219-00

700-047-04

700-028-02

400-083-00

700-058-02

710-020-00

12

13

14

15

16

17

18

18

19

20

21

22

24

25

3

3

4

2

3

7

8

5

6

9

11

INSL SILPAD K6 W/ADHESIVE




PIGGYBACK CLIP

MCH 4-40X1/2 SKT CLRZC

WASH NO.4 COMPRESSION

WASH FLAT NO.4 FENDER

BRACKET SUBSINK - M1200


TF 6-32X1/4 PHP BLKZC

WASH FLAT NO.6 FIBRE


SPRING CLIP SUBSINK-M1200


HEATSINK COWLING - M1200


FAN 80MM 24VDC-MECHATRONI

FAN 80MM 24VDC-PANASONIC

BRKT FAN PS - SR40.8



2P .100X1 22GA END



PARTS 19


COMPLETE PARTS LIST

040- Cables

055- Finished PCB Assys

100- Pots and Resistors

200- Capacitors

300- Semiconductors

400- Jacks/Connectors

500- Switches

510- Fuses

550- Chassis Metal

600- Transformers

601- Inductors

610- Wires and Cables

PART #

040-033-02

040-033-03

040-117-02

055-079-00

055-080-00

055-081-00

080-072-01

080-072-02

080-034-00

080-034-01

080-023-10

080-023-20

080-035-00

100-001-00

100-017-00

100-023-00

100-027-00

100-030-00

100-031-00

100-035-00

100-040-00

100-042-00

100-045-00

100-049-00

100-050-00

100-056-00

100-061-00

100-068-00

100-071-00

100-072-00

100-073-00

100-075-00

100-076-00

100-080-00

100-082-00

100-083-00

100-084-00

100-086-00

100-089-00

100-092-00

100-093-00

DESCRIPTION

RIB 28GA TRANS 20C 18IN

RIB 28GA TRANS 20C 4IN

RIB 28G TRNS 10C .10 11.5

PCB ASSY INPUT 1200/1400

PCB ASSY DISPLY 1200/1400




PCB ASSY SOFT START – 120V

PCB ASSY SOFT START – 240V

PNT HANDLE ASSY RIGHT

PNT HANDLE ASSY LEFT

PWR SW HARNESS - AMP

RES CF .125W 5% 10 OHM



RES CF .125W 5% 120 OHM

RES CF .125W 5% 160 OHM

RES CF .125W 5% 180 OHM

RES CF .125W 5% 300 OHM

RES CF .125W 5% 430 OHM

RES CF .125W 5% 510 OHM

RES CF .125W 5% 680 OHM

RES CF .125W 5% 1K OHM

RES CF .125W 5% 1K1 OHM

















PART #

100-094-00

100-097-00

100-109-00

100-110-00

100-111-00

105-277-00

105-331-00

110-036-00

110-046-00

115-427-00

121-097-00

123-009-00

123-033-00

123-056-00

123-071-00

123-085-00

123-109-00

123-124-00

125-020-00

130-017-02

130-036-00

130-037-02

130-038-00

140-025-00

140-057-00

140-060-00

140-065-00

140-068-00

140-073-00

140-076-00

140-078-00

140-080-00

140-081-00

140-083-00

140-087-00

140-089-00

140-092-00

140-094-00

140-097-00

140-106-00

140-108-00

640- AC Line Cords

700- Hardware

760- Knobs/Plastic

790- Misc./Packing

800- Printed Material

DESCRIPTION



RES CF .125W 5% 1M OHM



RES MF .125W 1% 750 OHM

RES MF .125W 1% 2K49 OHM



RES MF .25W 1% 24K9 OHM

RES MO 1W 5% 10K OHM

RES MO 3W 5% .22 OHM

RES MO 3W 5% 2.2 OHM

RES MO 3W 5% 20 OHM

RES MO 3W 5% 82 OHM

RES MO 3W 5% 330 OHM

RES MO 3W 5% 3.3K OHM

RES MO 3W 5% 13K OHM

RES WW 15W 5% 82 OHM CMNT

POT RTY 50KC 12MM DUAL TN

POT RTY 5KA 16MM DL DTNT

POT RTY 10KC 9MM TN

POT TRIM 500B HORIZ

RES TF SM .1W 5% 10 OHM





RES TF SM .1W 5% 1K0 OHM










RES TF SM .1W 5% 10K OHM



20 PARTS

VERSION 1.1

PART #

140-111-00

140-115-00

150-009-00

150-037-00

150-045-00

200-001-02

200-004-02

200-007-02

200-015-02

200-022-02

200-023-00

200-024-00

200-025-02

200-036-00

205-002-02

210-001-02

210-010-02

210-017-02

211-003-00

211-009-00

140-123-00

140-124-00

140-139-00

140-147-00

145-318-00

145-389-00

145-397-00

145-406-00

145-469-00

145-478-00

145-485-00

145-547-00

212-001-00

212-004-00

212-009-00

212-010-00

220-001-02

220-002-02

220-004-02

220-007-00

220-011-02

220-014-00

220-025-00

220-027-02

220-033-00

220-034-00

220-035-00

220-039-00

220-040-00

300-001-00

DESCRIPTION






RES TF SM .1W 5% 1M OHM

RES MF SM .1W 1% 2K00 OHM






RES MF SM .1W 1% 100K OHM

RES MF SM .1W 1% 442K OHM

RES FUS .25W 5% 2.2 OHM

RES FUS .25W 5% 33 OHM

RES FUS .25W 5% 68 OHM

PLY .012UF 10% 100V TR

PLY .047UF 10% 100V TR

PLY .01UF 10% 100V TR

PLY .0047UF 10% 100V PEI

PLY .47UF 5% 50V TR

PLY/BX .001UF 20% 250V Y2

PLY/BX .01UF 20% 250V Y2

PLY/BX .56UF 5% 63V TR

PLY/BX .1UF 10% 250V

MICA 270PF 5% 500V TR

CER .01UF +80/-20% 50V TR

CER 47PF 5% 500V NPO TR

CER 470PF 5% 500V Y5E TR

CER .001UF 10% 50V AX

CER .1UF 20% 50V AX

CER .01UF 10% 50V X7R SM

CER 220PF 5% 50V NPO SM

CER 47PF 5% 50V NPO SM

CER .1 +80/-20 25V Z5U SM

LYT 22UF 20% 25V RAD TR


LYT 470UF 20% 6.3V RAD TR

LYT 100UF 20% 100V RAD


LYT 2.2UF 20% 50V RAD



LYT 10000UF 20% 80V RAD

LYT .47UF 20% 100V RAD

LYT 12000UF 20% 80V RAD

LYT 1000 20 25V RAD SMDIA


DIO SIG 1N4148 100V 500MW

PARTS

PART #

300-003-00

300-007-00

310-023-02

310-028-00

310-029-00

310-032-02

310-033-00

310-034-00

310-035-00

310-036-00

310-037-00

310-038-00

310-042-00

310-043-00

311-002-00

320-004-00

323-001-00

323-002-00

329-012-00

329-014-00

301-006-00

301-007-00

301-008-00

301-009-00

301-010-00

301-014-00

302-001-00

302-003-00

304-001-00

304-004-00

310-002-00

310-007-00

400-059-00

400-060-00

400-061-00

400-065-00

400-077-00

400-078-00

400-083-00

400-118-00

400-119-00

400-129-00

400-133-00

400-134-00

400-135-00

400-138-00

400-141-00

400-142-00

400-143-00

400-171-00

DESCRIPTION

DIO SW DL4148 100V SM

DIO SW 1SS244-SUB 1SS245

THY 2N6507 400V

DIO PWR DUAL FEP30 (D7)

DIO PWR DUAL FEN30 (D8)

DIO PWR 1N4004

DIO PWR 1N5404 3A 400V

DIO PWR 1N4007

DIO ZEN 1N5261B 47V 500MW

DIO ZEN 1N4745A 16V 1W

LED RED T-1

LED GREEN T-1

XSTR PNP 2N4403

XSTR NPN 2N4401

XSTR NPN 2SC2362K TR

XSTR PNP 2SB940A POWER

XSTR NPN 2SD1264A POWER

XSTR PNP 2SA1016K TR

XSTR PNP MJL21193

XSTR NPN MJL21194

XSTR PNP 2SA1478

XSTR NPN 2SC3788

XSTR NPN MJE340 POWER

XSTR PNP MJE350

XSTR NPN MJE15032

XSTR PNP MJE15033

XSTR PNP MMST4403 SM

OPAMP 4560F

LM339 QUAD COMP

LM339D QUAD COMP SM

VTL5C10 OPTOCOUPLER

LM35DZ PREC TEMP SENSOR

TERM QDISC .250 MALE PCMT

FUSE CLIP PCMT 5MM DIA

HDR 2P .100X1 STR LOCK

TERM QDISC .250 F 18-22GA

HDR 20P .1X2 STR LCK SHRD

HDR 10P .1X2 STR LCK SHRD

2P .100X1 22GA END

JACK 1/4 HORIZ PCMNT MONO

TERM BANANA QUAD HRZ PCMT

FUSE CLIP .25 DIA PC MNT

HDR 6CK 11A/600V

RECP 6CK 11A/600V

TERM 11A/600V F 18-20GA

SPEAKONS HORIZ 4 CKT

XLR 3P F VERT A-SERIES

XLR 3P M VERT A-SERIES

HDR 3P .100X1 STR

HDR 2P .100X1 STR

21

PART #

400-172-00

400-173-00

550-223-10

550-223-20

550-224-00

550-225-00

550-237-00

550-244-00

550-247-00

550-249-00

550-255-00

550-275-00

550-277-00

551-029-00

551-029-10

551-032-00

553-002-01

553-002-03

553-006-03

553-007-03

400-210-00

400-214-00

410-003-00

500-022-00

500-023-00

500-024-00

501-002-00

510-017-00

510-021-00

550-219-00

550-221-00

550-222-00

553-010-03

553-015-03

553-017-01

600-016-00

601-006-00

611-029-02

611-038-00

660-005-00

700-005-00

700-010-00

700-010-04

700-011-00

700-028-02

700-028-04

700-041-04

700-047-04

700-050-04

700-055-00

DESCRIPTION

TERM SOLDER-IN 18AWG

TERM .25 QKDS PCMT STABLE

TERM QDISC .250 F 18-22GA

JACK 1/4 V PCMNT 1MM WASH


SW RCKR ILLUMINATED

SW SLIDE 4P3T MINI

SW SLIDE DPDT MINI

RELAY SPDT 30AMP 110VDC

FUSE SB 20A 3AB 1/4X1-1/4

FUSE FB 10A 5X20MM 250V

BRKT FAN PS - SR40.8

TOP COVER - M1200

BTM COVER - M1200

SIDE RAIL RIGHT - M1200

SIDE RAIL LEFT - M1200

BRACKET SUBSINK - M1200

HEATSINK COWLING - M1200

SPRING CLIP SUBSINK-M1200

BOTTOM COVER - M1400

SHIELD INPUT - M1200

PLATE XFMR MTG - M1200

PIGGYBACK CLIP

SPACER PLATE - AMPLIFIER

SCREEN MANIFOLD - M1400



EXTR FAB HEATSINK - M1200

CRS 18GA 36 X 120

CRS 18GA 48 X 120

EG 18GA 48 X 120

AL .063 48 X 120

EG 20GA 48 X 120

AL .125 1100 H14 48 X 120

SS .048 17-7 36 X 120

XFMR M1200 120V

INDUCTOR AIR COIL 1UH

WIR 18GA 1007 BLK 5IN ST2

WR 18G 1010 GN/YL 4IN ST2

22GA JUMPER WIRE




MCH 4-40X1/4 BTNSKT BLKOX







22 PARTS

PART #

700-058-02

700-059-00

704-001-01

704-001-02

704-007-01

704-023-03

705-001-00

705-003-00

705-013-00

705-015-00

705-018-00

706-036-01

706-036-03

706-045-00

710-002-00

710-013-00

710-017-00

710-019-00

710-020-00

710-022-00

710-023-00

710-024-00

711-001-00

712-020-00

712-021-01

740-004-00

760-048-04

760-061-00

770-006-00

770-007-00

780-042-00

780-114-00

790-002-00

790-016-00

800-066-00

800-069-00

810-056-00

820-062-00

820-062-10

830-016-00


DESCRIPTION


HEX 5/16-18X3IN GD-5

PEMNUT 6-32 .038 STL

PEMNUT 6-32 .054 STL

PEMNUT 4-40X.060L SS FLSH

STUD 6-32X.500 STL FLSH

KEPNUT 6-32

NUT (SPLD W/JACK)

NUT HEX M7 BLK

NUT SLOT NCKL SPLD W/JACK

NUT HEX 5/16-18 (GD-5)

6-32X.188L STL PEM

STDF 6-32X.312L STL PEM

SPCR PVC .770 LED HI TEMP

WASHER (SPLD WITH JACK)

WASH FLAT NO.6 FIBRE

WASH SPLTLCK 5/16 HEAVY

WASH FIBRE BLK (W/JACK)


WASH FLAT NO.4 FENDER

WASH STAR M7 .020 THK

WASH FLAT 5/16 HARD (USS)

LUG NO.6 SOLDER STAR

BRKT ANG 6-32X.037THK STL

RVT CL END .125X.062-.125

STRAIN RELIEF HEYCO 1244

KNOB 9MM DARK GRAY

KNOB VOLUME M1200

FAN 80MM 24VDC-MECHATRONI

FAN 80MM 24VDC-PANASONIC

INSUL MYLAR INPUT SHIELD

RUBBER WASHER - THIN

BAG POLY 12 X 18 2MIL

BAG POLY 24X30 4MIL-M1200

BOX M1200

BOX M1400

INST TOP/BOTTOM - AMP

OWN MNL - M1200/M1400

OWN MNL – M1400i

REG & WARR CARD FR SERIES

FR Series Fuse Upgrade

Model:

Serial #:

FR Series M1200/1400, 110V only

M1200 prior to SN# AF12626 Effective 4/28/97

M1400 prior to SN# AH12657

Problem: Original fuse (15A) rated too low. Turn on inrush current causes fuse to open.

Solution: Replace the main (F1) fuse with a 20A 250V slow blow fuse.

Attention!: Since you will be working directly with the AC power line, great care should be

taken in all aspects of the installation. Power should be disconnected from the unit prior to the installation process.

F1=20A

250V

Slow Blow

Top

View

FR Series Fuse upgrade BC 6/20/97

FR Tywrap Mod

Model:

Serial #:

FR Series M1200/1400

AFXXXXX to AFXXXXX Effective 5/8/97

Problem: The primary and secondary wires get pinched between the top cover and the fan shroud.

Solution: Install a 7 ½” tywrap through the fan shroud tunnels. (740-016-00 15 1/16” tywrap, cut to 7 ½”)

7 ½” 7 ½”

Tywrap

15 1/16”

7 ½” tywarp

Fan Front View

Top View

Top

View

Transformer secondary wires

Transformer primary wires

FR Tywrap Mod BC 4/28/97

FR series Amplifier ribbon replacement instructions (NEW! IMPROVED! July 2000)

*

Models affected: FR series M1200, M1400, M1400i

M1200: All models. M1400i: Before Serial # DA20889 and all models with “AM” prefix.

M1400 and 230v versions: Before Serial # DB12700 and all models with “AH” prefix.

Add this as part of your normal repair procedures.

Note: This bulletin replaces all previous ribbon bulletins.

Symptom:

Ch.1 or 2 output signal intermittently fades out, or cuts out completely and/or the DC supply rail fuses blow.

Possible Cause:

The two ribbon cables from the input board may be defective

Solution:

*

Replace the input ribbon cables with an improved type in all of the above models, (including any which have had the previous ribbon bulletin completed).

Safety Warning:

Caution! These instructions are for use by qualified personnel only. To avoid electric shock, do not perform any servicing unless you are qualified to do so. Refer all service to qualified personnel.

Tools Required:

Phillips screwdriver, Torx and Allen drivers, needle nose pliers, safety glasses.

Parts Required:

040-359-00

040-360-00

400-077-00

Ribbon cable, 28GA, 20 Pin, Length 4.25”, PLZD

Ribbon cable, 28GA, 20 Pin, Length 18”, PLZD

20 Pin Headers

Quantity = 1

Quantity = 1

Quantity = 2

Procedure:

1.

Remove all cords (including the power cable and speaker outputs) from the amplifier.

2.

Take off the top cover and inspect the ribbon cables. If they are not marked 040-359-00 or

040-360-00 then proceed as follows:

Remove the input board:

3.

Undo the XLR screws, TRS nuts, and pull out the four pot knobs.

4.

Disconnect the short ribbon cable from the amp board, and the long cable from the front panel display board. On later amplifiers, you will have to remove the front display board first.

5.

Disconnect the black ground wire from the amp board.

6.

Undo the four screws on the right side of the chassis. This will give enough room to pull out the input board. Catch the two metal XLR plates before they fall inside (not present on later amplifiers).

Ribbon

Input board

Ribbon

XLR plates

Continued....

Ribbon modification SSE July 2000

Ribbon mod.pdf, page 1 of 2

THE MACKIE FIXER MACKIE DESIGNS SERVICE NEWS

Procedure continued.

Input board work:

If the two ribbon cables are soldered to the input board, follow steps 7 to 11. If not, then go to step 12.

7.

Remove the metal shield plate and insulator sheet from the back of the input board.

8.

Carefully unsolder the ribbon cable headers from J16 and J11.

Discard part# 040-033-03, 4 inch ribbon cable.

Discard part# 040-033-02, 18 inch ribbon cable.

9.

Solder two new headers (#400-077-00) to the input board, with the cutout side pointing towards the center of the input board (i.e. downwards).

10.

Replace the metal shield plate and insulator sheet onto the back of the input board.

11.

Add part# 040-359-00, 4.25 inch ribbon cable to J11.

Add part# 040-360-00, 18 inch ribbon cable to J16.

Align each cable’s color stripe with the header’s pin 1.

Make sure both ribbons are fully inserted, then proceed to step 15.

If the two ribbon cables are not soldered to the board, follow steps 12 to 14.

12.

Discard part# 040-062-00, 4.25 inch ribbon cable.

Discard part# 040-062-02, 18 inch ribbon cable. You may have to undo the display board screws in order to remove it from J1.

13.

Add part# 040-359-00, 4.25 inch ribbon cable to J11.

Add part# 040-360-00, 18 inch ribbon cable to J16.

Align each cable’s color stripe with the header’s pin 1.

Make sure both ribbons are fully inserted.

14.

Refit the display board, once the long ribbon cable is securely attached to J1.

Putting the input board back in:

15.

Add the two metal XLR plates (where fitted) and carefully fit the input board back in place. Put the four pot knobs back after the board is in place.

16.

It can be difficult getting the knobs back on through the chassis holes, but you can make it easier by snipping off a bit of the plastic center ridge, as shown in the little knob diagram below.

17.

Add and tighten all the nuts and screws, and the four chassis screws (removed in step 6).

18.

Make sure that all ribbon cables are secure and that all ends are fully inserted.

19.

Reconnect the black wire from the input board to the amp board.

20.

Replace the top cover.

21/ Perform a complete specification and safety test before returning the unit to the customer.

Pin 1 Color Stripe

Input board

J11

Headers

J16 snip off knob

Ribbon modification SSE July 2000

Ribbon mod.pdf, page 2 of 2

M•1200/M•1400 INPUT PCB 055-079-00 REV-D

23

M•1200/M•1400 INPUT PCB 055-079-00 REV-D

24

M•1200/M•1400 DISPLAY PCB 055-080-00 REV-A

25

M•1200/M•1400 DISPLAY PCB 055-080-00 REV-A

26

M•1200/M•1400 MAIN PCB 055-081-00 REV-D

27

M•1200/M•1400 MAIN PCB 055-081-00 REV-D

28

M•1200/M•1400 MAIN PCB 055-081-00 REV-D

29

M•1200/M•1400 MAIN PCB 055-081-00 REV-D

30

M•1200/M•1400 SOFT START PCB 055-162-00 REV-A

31

M•1200/M•1400 SOFT START PCB 055-162-00 REV-A

32

Mackie FR Series M.800 Service manual

Go To Bulletins

M•1400 / M•1400i / M•1200

SERVICE MANUAL

Page 3 is interactive

CAUTION

RISQUE DE CHOC ELECTRIQUE

NE PAS OUVRIR

CAUTION: TO REDUCE THE RISK OF

ELECTRIC SHOCK DO NOT REMOVE

THE COVER

NO USER SERVICEABLE PARTS INSIDE

REFER SERVICING TO QUALIFIED

PERSONNEL

WARNING: TO REDUCE THE RISK OF

FIRE OR ELECTRIC SHOCK, DO NOT

EXPOSE THIS PRODUCT TO RAIN OR

MOISTURE

TO PREVENT ELECTRIC SHOCK, DO

NOT USE THIS POLARIZED PLUG WITH

AN EXTENSION CORD, RECEPTACLE OR

OTHER OUTLET UNLESS THE BLADES

CAN BE FULLY INSERTED TO PREVENT

BLADE EXPOSURE.

ATTENTION: POUR EVITER LES

RISQUES DE CHOC ELECTRIQUE, NE

PAS ENLEVER LE COUVERCLE. AUCUN

ENTRETIEN DE PIECES INTERIEURES

PAR L'USAGER. CONFIER L'ENTRETIEN

AU PERSONNEL QUALIFIE.

AVIS:POUR EVITER LES RISQUES

D'INCENDIE OU D'ELECTROCUTION,

N'EXPOSEZ PAS CET ARTICLE A LA

PLUIE OU A L'HUMIDITE.

POUR PREVENIR LES CHOCS

ELECTRIQUES NE PAS UTILISER CETTE

FICHE POLARISEE AVEC UN

PROLONGATEUR, UN PRISE DE

COURANT OU UNE AUTRE SORTIE DE

COURANT, SAUF SI LES LAMES

PEUVENT ETRE INSEREES A FOND

SANS LAISSER AUCUNE PARTIE A

DECOUVERT.

TABLE OF CONTENTS

Click on any item to open that page

INTRODUCTION

SERVICE ON THE M•1200/M•1400 IS

TO BE PERFORMED BY EXPERIENCED

TECHNICIANS ONLY!

! SMD !

SYSTEM OVERVIEW

CIRCUIT THEORY

SERVICE PROCEDURES

PARTS

1 2

3

16 17 18

4

1 7

10

9

11

5

12

6

1

8

13

14

15

FR Series Fuse Upgrade

F1=20A

250V

Slow Blow

FR Tywrap Mod

FR series Amplifier ribbon replacement instructions (NEW! IMPROVED! July 2000)

Models affected: FR series M1200, M1400, M1400i

Symptom:

Possible Cause:

Solution: