OC-1 AWCS-II Option Card

®

© 1994 Bose Corporation

Service Manual

TABLE OF CONTENTS

1. SPECIFICATIONS....................................................................................................

2

2. THEORY OF OPERATION....................................................................................... 3

3. EQ CURVES............................................................................................................. 5

4. BLOCK DIAGRAM....................................................................................................

8

5. INSTALLATION INSTRUCTIONS........................................................................... 9

6. TEST PROCEDURES..............................................................................................

12

7. PARTS LIST ..........................................................................................................

16

CAUTION: THE OC-1 OPTION CARD CONTAINS NO USER SER-

VICEABLE PARTS. TO PREVENT WARRANTY INFRACTIONS, REFER

SERVICING TO WARRANTY SERVICE STATIONS OR FACTORY SERVICE.

PROPRIETARY INFORMATION

THIS DOCUMENT CONTAINS PROPRIETARY INFORMATION OF

BOSE

®

CORPORATION WHICH IS BEING FURNISHED ONLY FOR

THE PURPOSE OF SERVICING THE IDENTIFIED BOSE PRODUCT

BY AN AUTHORIZED BOSE SERVICE CENTER OR OWNER OF THE

BOSE PRODUCT, AND SHALL NOT BE REPRODUCED OR USED

FOR ANY OTHER PURPOSE.

1

Dimensions:

Weight:

Input/Output:

Input Impedance:

(feedback input)

Output Level:

Crossover Frequency:

Output Noise:

Channel Separation:

OC-1 SPECIFICATIONS

.63" Hx1.29"Wx8.98"D(1.6x3.3x22.8 cm)

.09 lbs. (.042 kg.)

2 audio inputs,Channel 1 and 2 high frequency outputs, bass channnel output

482 k

Ω

(nominal)

5.0 Vrms into 10 k

Ω

125 Hz,Roll-off slope: 24 dB/oct.

≤

40

µ

V (A-weighted)

50 dB (min.) @ 5 kHz

2

THEORY OF OPERATION

Overview

The OC-1 is a small plug-in module for use with Bose 502™, 402™, and 802 ® II controllers. The

OC-1 allows the use of the Cannon™ bass loudspeaker with these controllers and their loudspeakers. Refer to the block diagram, equalization curves and OC-1 schematic for further information.

The OC-1 provides three major functions:

A. Low frequency equalization.

B. Crossover filtering of the high frequency signals.

C. Protection of the Cannon against excessive power.

1. Low Frequency Equalization Circuit

U5's four op-amp stages provide low-pass crossover filtering, high-pass filtering to eliminate subsonic material, and frequency contouring to optimize the overall response.

2. High Frequency Equalization Circuit

U3, section 1 and U5, section 2 provide two channels of high-pass filtering to remove bass from the main loudspeakers.

3. Protection Circuit

The protection circuit consists of a compressor and a mute circuit. The protection circuit is connected so that it can monitor the low frequency voltage applied to the Cannon driver. When this voltage exceeds the power limit defined for the driver, a compressor begins to reduce the gain in the low frequency path so that the power does not continue to rise.

4. Compressor Circuit

The compressor consists of the following functional blocks:

A. Differential input buffer

B. Full-wave peak detector/comparator

C. Averaging circuit

D. Voltage-controlled amplifier (VCA)

The differential input buffer (U1 section 1) features protection against Radio Frequency

Interference (RFI), Electrostatic Discharge (ESD), and overvoltage. It has a gain which is much less than 1 so that it can attenuate the high level signals coming from the Cannon (over 40 volts at full power).

3

U4, sections 1 and 2 form a full-wave peak detector. When the input to these stages exceeds

+/-2V peak, the outputs go high and a control voltage is created in the averaging circuit (C27, C28, etc.). The averaging circuit captures peaks with a short attack time and holds them with a longer release time. U2, section 2 inverts and scales the averaged control voltage and applies it to the

VCA control input.

U7 is a current-in/current-out VCA which is controlled by the voltage on pin 2.

5. Mute Circuit

The mute circuit acts as a watchdog, and prevents the Cannon™ from operating unless the feedback signal from the Cannon is connected properly to the controller/OC-1 protection input.

When the mute circuit detects that no audio has occurred for about two minutes, it reduces the gain in the low frequency path.

The mute circuit consists of a gain stage and a comparator. U1, section 2 amplifies the signal from the protection circuit differential input, and U2, section 1 compares it to a reference. When the sensed level exceeds the threshold, a control voltage (generated in U2, section 2) causes U2,

section 1 to go from high to low and reduces the compressor gain by about 40 dB.

4

Output is measured from U3 pin 7 or U6 pin 1. Controls are set at:: Mode 4 (Option),

Output Mode: Normal, Low Frequency Level: 0 dB, and Input Level: +4 dB.

Figure 1. High Frequency EQ

Output is measured from U5 pin 14. Controls are set as in Figure 1.

Figure 2. EQA + EQB

5

Output is measured from U5 pin 1. Controls are set as in Figure 1.

Figure 3. EQA + EQB + EQC

Output is measured from U5 pin 7. Controls are set as in Figure 1.

Figure 4. EQA + EQB + EQC + EQD

6

Output is measured from U3 pin 1. Controls are set as in Figure 1.

Figure 5. EQA + EQB + EQC + EQD + VCA

7

Figure 6. OC-1 Block Diagram

8

OC-1 Installation Procedures

NOTE: The information included here is to aid the technician in setting up the OC-1 before doing any troubleshooting. These procedures are provided in more depth in the OC-1 Owner's

Guide (P/N 176007).

OC-1 Option Card

Internal Protection

Circuit Harness

External Protection

Circuit Harness

Figure 7. OC-1 Option Card and Harnesses

1. Installing the Internal Protection Circuit

Harness

A. Turn the controller so that its rear panel faces you. See Figure 8.

B. Remove 4 phillips-head screws.

C. Slide the cover towards you and lift away from the controller.

D. Find the plastic plug in the controller's rear panel (Figure 9). Pinch the top lock tab and push the plug partially out (Figure 9A).

Release the tab and pull the plug completely out.

9A

Figure 8. Cover and screw removal

9

Figure 9. Plastic plug removal

10A

Flat side of barrel

10B

10C

Figure 10. Internal Harness Connection

E. Remove the lock nut and washer from the harness (Figure 10A).

A. Turn the OC-1 PCB so that its component side faces you.

F. Thread the harness through the rear panel (white connector first).

B. Connect the harness to J1 on the OC-1

PCB (Figure 11).

G. Turn the barrel connector so that its flat side matches the flat side of the hole in the controller. The connector should sit firmly against the outside of the rear panel (Figure

10B).

C. Plug the PCB into the connector receptacles located on the controller's PCB.

See Figure 12 for proper orientation.

3. Installing the External Protection Circuit

Harness

H. Replace the lock nut and washer on the harness inside the rear panel. Tighten firmly with needle nose pliers (Figure 10C).

2. Connecting the OC-1 to the controller

A. Attach the external harness to the internal harness connector (Figure 13) by turning the notch on the harness to the right.

NOTE: The controller's rear panel should face you and the internal harness should be inside.

B. Hand tighten the lock nut on the external harness.

Figure 11. System Controller Connection

10

Figure 12. OC-1 connected to controller PCB

Figure 13. External Harness Connection

C. Connect the harness's other end to the speaker terminals on your amplifier with either screw lugs (Figure 14A) or a banana plug (Figure 14B). Connect the red wire to the positive (+) terminal and the black wire to the negative (-) terminal.

NOTE: Figure 15 shows a typical system hookup.

Figure 14A. Screw terminal Figure 14B. Banana plug

Figure 15. Complete system hookup

11

Test Setup

OC-1 Test Procedures

• Output mode switch should be set at

normal

Input Connections: Connect an oscillator to the positive (+) and negative (-) input terminals for

Channels 1 or 2. These procedures assume that the person performing these tests is using test equipment with unbalanced inputs and outputs.

See Figure 16 for connection information. Also, refer to Figure 15 for a system hookup diagram.

• Input switches should be set at +4 dB

• Low frequency level potentiometer should be set at 0 dB

Output Connections: Connect test equipment to the positive (+) and negative (-) output terminals for Channels 1 or 2 (low and high frequency outputs).

**IMPORTANT NOTE**

All tests should be performed for both channels.

Install the external protection circuit harness for all tests. Otherwise, the controller's bass channel (as a safety measure) will shut down.

All test equipment must be isolated from ground (floated).

1. Frequency Response of High Frequency (HF)

Output

See Figure 17 for a picture of the controller's back panel.

A. Apply a 100 mVrms, 600 Hz signal to the controllers's input terminals and reference your dB meter to this frequency.

The controls on the back panel should be set as follows:

• Mode switch should be set at 4 (Option)

B. Measure the frequency response across the

HF outputs according to the chart below. This chart provides responses for the 402, 502, and

802 II controllers (with the option card installed).

Frequency (Hz)

40

80

100

120

150

180

200

600

2200

5000

15000

402™ Controller 502™ Controller

Response (dB) Response (dB)

-29.2

±

1.5 dB -23.5

±

1.5 dB

-8.3

±

1.5 dB - 5.6

±

1.5 dB

-3.0

±

1.5 dB +0.8

±

1 .5 dB

+1.6

±

1 .5 dB 0 dB

+1.83

±

1.5 dB +1.93

±

1.5 dB

+2.16

±

1.5 dB +0.7

±

1.5 dB

+2.11

±

1.5 dB +.15

±

1.5 dB

REF REF

+2.12

±

1.5 dB +3.5

±

1.5 dB

+7.5

±

1.5 dB +12.5

±

1.5 dB

+12.85

±

1.5 dB +19.0

±

1.5 dB

802® II Controller

Response (dB)

-17.57

±

1.5 dB

-1.84

±

1.5 dB

+2.0

±

1.5 dB

+4.0

±

1.5 dB

+4.7

±

1.5 dB

+4.2

±

1.5 dB

+3.7

±

1.5 dB

REF

+1.61

±

1.5 dB

+7.29

±

1.5 dB

+17.02

±

1.5 dB

12

Audio

Oscillator

Input Connections

Audio

Oscillator

Output Connections

Figure 16. Unbalanced Connections

Input connectors

SER. NO.

INPUT LEVEL

–10 +4

D.O.M.

+

CH 1

–

INPUT

+ –

CH 2

INPUT LEVEL

–10 +4

PROTECTED BY U.S. PATENT 3,038,964

MODE

4

3

2

1

High frequency output connectors

Bass level control

HIGH FREQ OUTPUT

+ –

CH 1

+ –

CH 2

Low frequency output connectors

LOW FREQ

.

LEVEL

.

0

.

-18 +3

OUTPUT MODE

NORM SUM

BOSE CORPORATION, FRAMINGHAM, MA 01701-9168

ENGINEERED AND MANUFACTURED IN U.S.A.

LOW FREQ OUTPUT

+ –

CH 1

+ –

CH 2

230V

~

AC

50/60Hz 12W

LISTED 411F

U

® L

COMMERCIAL

SOUND

EQUIPMENT

Input attenuator switches

Mode switch

Bass mono sum switch

Figure 17. Typical Controller Back Panel (Barrier Strip Version Shown)

13

2. Frequency Response of LF Output

A. Apply a 100 mVrms, 80 Hz signal to the controller's input terminals and reference your dB meter to this frequency.

B. Measure the frequency response across the

LF outputs according to the chart below.

Frequency (Hz)

20

50

80

100

120

150

180

200

Response (dB)

-10.5

±

1.5

+2.25

±

1.5

REF

-7.35

±

1.5

-13.68

±

1.5

-21

±

1.5

-27

±

1.5

-30.5

±

1.5

3. Protection Circuit Test

NOTE: Refer to Figures 13 through 15 and the installation instructions for connecting the external protection circuit harness.

A. Connect a signal generator to the controller input terminals.

B. Connect the controller LF outputs to the amplifier input terminals.

C. Connect the external protection circuit harness to the amplifier output.

D. Connect a voltmeter across the amplifier output terminals.

E. Apply a 57 Hz signal to the controller input terminals and adjust the signal generator until the amplifier's output voltage is 40 Vrms.

F. Increase the input to the amplifier until the output voltage is 47 Vrms. Continue increasing the input to the amplifier. The amplifier's output voltage should not rise above 47 volts

(compression occurs at this voltage).

14

Notes for Future Reference

15

OC-1 Option Card Parts List

OC-1 Packaging Parts List (Figure 16)

Part Number

-

-

-

-

-

Item

Number

1

2

Description

Cable Assembly

Option Card PCB Assembly

Bag-Antistatic

Card-Owner's Registration

Envelope

Owner's Manual

Carton

174147

145610

174138

122157

122785

176007

145618

Qty.

Per

Carton

1

See Note

1

2,3 1

1 4

4 1

1 4

4 1

N/A 4

NOTES

1. The cable assembly consists of both the internal and external protection circuit harnesses.

2. This part is not normally available from Customer Service. Approval from the field service manager is required before ordering.

3. The individual parts located on this PCB are listed in the Electrical Parts List.

4. This part is not illustrated.

16

Option Card (2)

Internal Protection

Circuit Harness

Cable Assembly (1)

External Protection

Circuit Harness

Figure 16. Option Card and Cable Assembly

17

OC-1 Electrical Parts List

R33,36

R34

R35

R38

R45

R48

R50

R16

R18

R19,25,28

R22

R24

R26,29

R27,30

R32,37

R1-4

Reference

Designator

R6,7,41,75,76

R8,39

R9,10,12,14

R11,17

R13,90,93

R15

Resistors

Description

475 K

Ω

,1%,1/4W,

52mm,MF

7.5 k

Ω

,1%,

1/10W,0805

100

Ω

,1%,

1/10W,0805

200 k

Ω

,5%,

1/10W,0805

1 M

Ω

,5%,1/10W,

0805

10 k

Ω

,1%,

1/10W,0805

51

Ω

,5%,1/10W,

0805

4.64 k

Ω

,1%,

1/10W,0805

12.4 k

Ω

,1%,

1/10W,0805

20 k

Ω

,1%,1/10W,

0805

41.2 k

Ω

,1%,

1/10W,0805

5.1 k

Ω

,5%,1/10W,

0805

7.87 k

Ω

,1%,

1/10W,0805

137 k

Ω

,1%,

1/10W,0805

17.4 k

Ω

,1%,

1/10W,0805

100 k

Ω

,1%,

1/10W,0805

2.43 k

Ω

,1%,

1/10W,0805

2.94 k

Ω

,1%,

1/10W,0805

301

Ω

,1%,

1/10W,0805

750

Ω

,1%,

1/10W,0805

1.54 k

Ω

,1%,

1/10W,0805

35.7 k

Ω

,1%,

1/10W,0805

Part Number

121245-2214753

133625-7501

133625-1000

133626-2045

133626-1055

133625-1002

133626-5105

133625-4641

133625-1242

133625-2002

133625-4122

133626-5125

133625-7871

133626-1373

133625-1742

133625-1003

133625-2431

133625-2941

133625-3010

133625-7500

133625-1541

133625-3572

See Note

18

Resistors (Continued)

Reference

Designator

R52,58,64,65,69,

77,78,83,89,94

R54,62,63

R85

R88

R92

R95

Description

Jumper-Chip,0805

14 k

Ω

,1%,

1/10W,0805

26.1 k

Ω

,1%,

1/10W,0805

178 k

Ω

,1%,

1/10W,0805

1.4 k

Ω

,1%,1/10W,

0805

255 k

Ω

,1%,1/10W,

0805

D1,4

Reference

Designator

D2,3,9

D5,6

D7,8

Reference

Designator

U1-4,6

U5

U7

Part Number

133627

133625-1402

133625-2612

133625-1783

133625-1401

133625-2553

Diodes

Description

Zener,5%,18V,1W

1N4746

Dual,SOT-23

1N4148,75V,

300mA,Switching or

Dual,SOT-23

Part Number

116995-4746A

147239

121501

116997

147249

Integrated Circuits

Description Part Number

Op Amp,RC4559,

Dual

Op Amp-

NJM2059,Quad

VCA, 18V, SIP-8,

2155

108568

144008

175120

J1

Reference

Designator

J4,5

Description

Header,2 pos,

Male

Header,Rtang,

12 pos.

Connectors

Part Number

134739-02

149358

See Note

See Note

See Note

See Note

19

Capacitors

Reference

Designator

C1,2,57

C3

C4,7,13,27,28

C5,6,8,9,18,19,

23-26,38,39,59

C10

C11

C14

C15-17,20-22

C35

C42

C43

C48,51

C52,54,55

Description

3300 pF,10%,50V,

X7R,0805

100

µ

F,20%,25V,

105,Electrolytic

10

µ

F,20%,16V,

105,Electrolytic

.022

µ

F,10%, 50V,

X7R,0805

22

µ

F,20%,25V,

BP,EL

1

µ

F,20%,50V,

105,Electrolytic

100 pF,5%, 50V,

Cog,0805

.047

µ

F,5%, 63V,

85,Box

.18

µ

F,5%, 50V,

85,Box

.027

µ

F,5%, 63V,

85,Box

.47

µ

F,5%, 50V,

85,Box

.22

µ

F,5%, 50V,

85,Box

.15

µ

F,5%, 50V,

85,Box

Part Number

133623-332

120767

137126-100

133623-223

147522-220

137126-1R0

133622-101

137127-473

137127-184

137127-273

137127-474

137127-224

137127-154

See Note

20

SPECIFICATIONS AND FEATURES SUBJECT TO CHANGE WITHOUT NOTICE

®

Bose Corporation

The Mountain

Framingham, Massachusetts USA 01701

P/N 174786 6/94: REV.0 FOR TECHNICAL ASSISTANCE OR PARTS ORDERING,CALL 800-367-4008