Bose 1801 Service Manual

Bose® Model 1801/1800Power AmplifierSupplementPart Number 192527-S1©2001 Bose Corporation10/2001SUPPLEMENTQ4, part number 102428 and Q5, part number 1

9TEST PROCEDURES1. Bias Adjustment Setup and Procedure1.1 Locate the -85V negative terminalfound on the capacitor (C4). See Figure 1for the locatio

10Figure 1. 1801 Component LocationFigure 2. 1801 Side View

11Figure 4. 1800 Rear View of Front PanelFigure 5. 1801 Rear View of Front PanelFigure 3. 1800 Front Panel

12Figure 7. 1801 Rear PanelFigure 6. 1800 Rear Panel

13PART LIST NOTES1. This part is not normally available from Customer Service. Approval from the Field ServiceManager is required before ordering.2.

14PART LISTItemNumberDescription PartNumberNoteA1 Preload Network 102666 6RT-1, RT-2 Thermal Cut-Out 102440 6¥ RCA Jack 102784 6, 9Q10-23 Screw, 6/32

15PART LISTMain Part List (per figures 1-7)ItemNumberDescription PartNumberNote8 Rubber Foot 121929F1 Fuse (110v)15A, 1 1/4 x 1/4Slo-Blo 103608F1 Fuse

16PART LISTResistorsReferenceDesignatorDescription Part NumberNoteR1-4 1MΩ, 1/2W, 10% 102944-105 3R2 8.2kΩ, 1/2W, 10% 104064-822R3 3kΩ, 2W, 10% 10867

17PART LISTDiodes and TransistorsCapacitorsReferenceDesignatorDescription PartNumberNoteC1‡, 2‡ 1uF, Mylar, 50v, 10% 102751 4C1, 14, 15 .1uF, Electrol

18Figure 9. 1801/1800 Block DiagramBridge RectifierTurn On Relay

1 PROPRIETARY INFORMATIONTHIS DOCUMENT CONTAINS PROPRIETARY INFORMATION OFBOSE® CORPORATION WHICH IS BEING FURNISHED ONLY

Figure 10. LED PCB Layout19

20Figure 11. LED PCB Schematic Diagram

21Notes:1. See Bias Adjustment Procedure.2. U1 input (pin 2) virtual ground, output test point 8 (pin 6) 275mV.3. Early production units replace R2

Figure 13. Amplifier PCB Layout22

23TROUBLESHOOTING GUIDESYMPTOM POSSIBLE CAUSE1. DC Offset: ≤2v Defective U1Defective Q1

24VOLTAGE CONVERSION INSTRUCTIONS1. Perform Top Cover removal procedures for the model amplifier your going to convert.2. Refer to the figures below

25Subject: Interchangeability of repaired amplifier PCB. Torroidal Power Transformer. 1800 Amplifier used with a TC-1

26SERVICE BULLETINSubject: Resistor Failure Date: 09/19/1977Remarks:We have found that t

27SERVICE BULLETINSubject: Thermal Improvement Date 10/05/1979Remarks:I'm pleased to inform you that we

28SERVICE BULLETINSubject: Output Transistors Date: 10/13/1980Remarks:Due to supply demands, Bose® Corporati

2SPECIFICATIONSMechanicalDimensions: 180118007 3/16" H x 18" W x 18 1/2" D (Including Knobs)81/4"H x 19"W x 15"D (not

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®®Bose Model 1801/1800 Power Amplifiers©1997 Bose CorporationPart Number 192527 REV 01Service Manual

SPECIFICATIONS AND FEATURES SUBJECT TO CHANGE WITHOUT NOTICE®®Bose CorporationThe MountainFramingham Massachusetts USA 01701P/N 192527 REV. 01 06/97 F

3SAFETY INFORMATION 1. Parts that have special safety characteristics are identified by the symbol on schematics or

4ELECTROSTATIC DISCHARGE SENSITIVE (ESDS)DEVICE HANDLINGCAUTION: THE BOSE® 1801/1800 POWER AMPLIFIERS CONTAIN NO USER-SERVICE-ABLE PARTS. TO PREVENT

5DISASSEMBLY/ASSEMBLY PROCEDURES1801 Power AmplifierNote: Refer to Figure 1 for the followingprocedures.1. Top Cover Removal1.1 Remove the two scre

61801 Power AmplifierDISASSEMBLY/ASSEMBLY PROCEDURESassembly. Connect the wires going to themeter.12.2 Place the meter lamp housing overthe meters an

7DISASSEMBLY/ASSEMBLY PROCEDURES5.2 Locate and remove the eight screwsholding the front panel to the chassis. Fourof the screws are located just insi

81800 Power AmplifierDISASSEMBLY/ASSEMBLY PROCEDURES13. Rear Panel Removal13.1 Perform procedure 1.13.2 Locate and remove the four screwssecuring t