6Thermal Cutoff Procedure

6.1 Apply a signal to the unit with the outputs loaded ( 8 or 4 ohms ). Short one channel at a time until the unit goes into thermal cutoff. The thermal indicator should turn on and the output of the unit should be off.

6.2 Disconnect the short from the output. Wait until the unit comes out of thermal cutoff. You can speed this process by cooling the PCB with a fan.

6.3 Once the unit is cooled apply a signal to the channel you had shorted to check to see if its operational.

6.4 Apply a signal to the other channel and short the output. Wait for the thermal indicator to come on then remove the short and cool the PCB.

Bose 1800 Power Amplifier
Figure 2. 1801 Side View

oo oo oo oo oo oo oo

Figure 3. 1800 Front Panel

Figure 3. 1800 Front Panel

Figure 4. 1800 Rear View of Front Panel

"P

Bose1800 Apartments

Figure 4. 1800 Rear View of Front Panel

Figure 5. 1801 Rear View of Front Panel
Bose1800 Apartments
Figure 7. 1801 Rear Panel

1. This part is not normally available from Customer Service. Approval from the Field Service Manager is required before ordering.

2. The reference designators in bold are located on the LED PCB.

3. This part is not located on the PCB'S.

4. The reference designators marked with a t symbol are located on the Front Panel.

5. The part numbers listed with SIM are selected components and may not be directly interchangeable with standard available parts.

6. This part is located on the amplifier PCB.

7. This part is used on the 1801 Power Amplifier.

8. This part is used on the 1800 Power Amplifier.

9. Items marked with a ¥ symbol are not shown in the exploded views.

Figure 8. 1801 Front Panel
Main Part List (per figures 1-7)

Item

Description

Part

Note

Number

Number

A1

Preload Network

102666

6

RT-1, RT-2

Thermal Cut-Out

102440

6

¥

RCA Jack

102784

6, 9

Q10-23

Screw, 6/32 x 1/2 Stainless Steel

106348

6

Q10-23

Washer

103032

6

Q10-23

Plastic Insulator

102901

6

Q10-23

Nut, Brass, 6/32 x 5/16 x 1/8

103016

6

Q4, 5

Heat Sink Assy

102571

6

¥

Top Wiring Harness

102929-1

1, 7, 9

¥

Bottom Wiring Harness

103281-1

1, 7, 9

¥

Top Wiring Harness

103365

1, 8, 9

¥

Bottom Wiring Harness

103366

1, 8, 9

¥

Audio Cable

102838

9

S1

Toggle Switch, ON/OFF

103291

8

S1

Switch, ON/OFF

102740

7

S2

Input Switch

102576

7

S3

Speaker Switch

103400

7

J3, 4 (J5, 6 1801 )

Phone Jack

102704

R5, 6

Gain Control, 100kQ

102406

7

R5, 6

Gain Control, 100kQ

103260

8

1

Indicator Lens, White

103479-1

2

Indicator Lens, Red

103479-0

3

Lens Housing

103478

4

Front Handle

121914

8

5

Knob

128907

7

5

Knob

121911

8

M1, 2

VU Meters

102570

7

B1-4

Meter Lamps

103063

7

B5, 6, 7

LED / Bose® Logo Lamp 1847

102580

7

B8

Thermal Cutout Indicator

102582

7

K1

Start-up Relay

102818

6

Accy Outlet

107558

7

Line Cord

103441

T1

Transformer

102434

1, 7

T1

Transformer (110v)

110185

1

T1

Transformer (220v)

112669

1

Main Part List (per figures 1-7)

Item

Description

Part

Note

Number

Number

8

Rubber Foot

121929

F1

Fuse (110v)15A, 1 1/4 x 1/4Slo-Blo

103608

F1

Fuse (220v) 8A, 5 x 20mm

108190-800

F1

Fuse (220v) 7A, 1 1/4 x 1/4Slo-Blo

103609

¥

Fuse Cap for 1 1/4 x 1/4

109484

9

¥

Fuse Cap for 5 x 20mm

109493

9

9

Front Panel Assy

103380

1, 7

10

Front Panel Assy

121910

1, 8

11 ¥

Rear Panel Assy

103282

1, 7, 9

12

Rear Panel Assy

103266

1, 8

13

Amp PCB Complete

102735-1

1

14

L.E.D Board Complete

102751

1

Carton and Fillers

103268

15

Heat Sink Side

102536

1

16

Heat Sink Corner

102474

1

17

Top Cover

102544

1, 7

18

Top Cover

121930

1, 8

19

Screw Heat Sink

103041

¥

Accessory Kit

102745

1, 7, 9

¥

Accessory Kit

103361

1, 8, 9

20

Black Binding Post

109068-0

21

Red Binding Post

109068-2

22

Blue Binding Post

109068-6

23

Black Binding Post Base

109069-0

24

Fuse Holder

109485

25

Strain Relief

102708

Plug, double banana red, 103362-2 blue, 103362-6 black, 103362-0

Plug, double banana red, 103362-2 blue, 103362-6 black, 103362-0

Resistors

Reference Designator

Description

Part Number

Note

R1-4

1MQ, 1/2W, 10%

102944-105

3

R2

8.2kQ, 1/2W, 10%

104064-822

R3

3kQ, 2W, 10%

108676-302

R9, 17

6.19Q, 1/4W, 1%

104095-6191

R11

1.5kQ, 1/4W, 1%

104095-1501

R12, 51, 53

340Q, 1/4W, 1%

104095-3400

R13

100Q, Bias Pot

102832

R18, 20, 48

23.7kQ, 1/4W, 1%

104095-2372

R25, 26

182Q, 1/4W, 1%

104095-1820

R31-36, 41-46

0.8Q, Wirewound, 3W, 5%

102394

R37-39

0.4Q, Wirewound, 6W, 5%

102395

R47

4.7Q, 2W, 5%

102393

R50

470Q, 1/2W, 5%

102942-471

R52, 54

10kQ, 1/4W, 1%

104095-1002

R55, 57

100kQ, 1/4W, 1%

104095-1003

R56

680Q, 1/2W, 5%

102942-681

R1,3,101,103

5.1kQ, 1W, 5%

104064-512

2

R2,4,10,13,16,19

150Q 1/2W, 5%

102942-151

102,104,107,110

2

113,116,119

R5,105

3.6kQ, 1W, 5%

104064-362

2

R6,9,106,109

2kQ, 1/2W, 5%

102942-202

2

R8,108

8.2kQ, 1W, 5%

104064-822

2

R11,111

12kQ, 1/2W, 5%

102942-123

2

R12,15,18,112,

1kQ, 1/2W, 5%

102942-102

115,118

2

R14,114

24kQ, 1/2W, 5%

102942-243

2

R17,117

43kQ, 1/2W, 5%

102942-433

2

R20,120

15kQ, 1/2W, 5%

102942-153

2

R21,121

120Q, 1/2W, 5%

102942-121

2

R22,122

18kQ, 1/2W, 5%

102942-183

2

Capacitors

Reference Designator

Description

Part Number

Note

C1t, 2t

1uF, Mylar, 50v, 10%

102751

4

C1, 14, 15

.1uF, Electrolytic, 100v, 10%, NP

102403

C1,101

100uF Electrolytic, 3v

102836

2

C2, 3

30uF Electrolytic, 100v

102405

C3, 4

14,000uF, Electrolytic, 100v

102438

3

C5

18,000uF, Electrolytic, 10v

104229

3

C5, 16

27pF, Ceramic Disc, 25v, 10%

102397

C6, 7, 10, 11

.01uF, Ceramic Disc, 25v, 10%

102399

C8

200pF, Ceramic Disc, 200v, 10%

102400

C9

300pF, Ceramic Disc, 200v, 10%

102396

C12, 13, 17

1000pF, Ceramic Disc, 200v, 10%

102453

Diodes and Transistors

Reference Designator

Description

Part Number

Note

D1-4

Bridge Rectifier

102578

D5-8

Diodes

102422

CR1-4, 7, 16, 17 CR10-17,110-117

Diode 1N4148

116997

2

CR1-9,101-109

LED Diode

106864

2

CR5, 18, 19

Diode SIM 1N3070

102411

CR6, 15

Diode 1N5425, Zener, 15V, 1/2w

102423

CR8-14, 20, 21

Diode SIM 1N4003

102422

Q1

SIM MM-4001

102425

5

Q2, 8 Q2,102

SIM 2N3906

102426

5 2

Q3

SIM 2N6175

102427

5

Q4

SIM 2N2219

102428

5

Q5

SIM 2N5415

102429

5

Q6

SIM 2N3584

102430

Q1,3-10,101,103-110

SIM 2N3904

102432

5 2

Q9

SIM 2N6211

102431

5

Q10-23

MJ15011

117579

U1

Integrated Circuit, MC1556G

102409

110v Omin Relay Diagram

Turn On Relay

Figure 9. 1801/1800 Block Diagram

Turn On Relay

Figure 9. 1801/1800 Block Diagram

Bose 1801 Pcb27pf 200 Capacitor

-85V

GROUND

NOTES:

1. All capacitors in MFD.

2. All resistors are 1/2W 5% unless otherwise stated.

3. For "0" dB LED indication, amplifier output is 2 Volts at 8 Ohms.

-85V

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