Q4, part number 102428 and Q5, part number 102429 are no longer available with the lead length needed for soldering to the PCB. Use the part numbers listed below when ordering these transis- tors. Make a note in your Model 1801/1800 power amplifier service manual, part number 192527. Reference...
SPECIFICATIONS Mechanical Dimensions: 1801 7 3/16" H x 18" W x 18 1/2" D (Including Knobs) 1800 81/4"H x 19"W x 15"D (not including handles) Weight: 1801 82 lbs 95 lbs (shipping) 1800 80 lbs 91 lbs (shipping) Power Requirements...
SAFETY INFORMATION 1. Parts that have special safety characteristics are identified by the symbol on schematics or by special notes on the parts list. Use only replacement parts that have critical characteristics recommended by the manufacturer. 2. Make leakage current or resistance measurements to determine that exposed parts are acceptably insulated from the supply circuit before returning the unit to the customer.
They use computer grade capacitors throughout the power supply, along with a 2.0kW power transformer and 1300 sq. inches of heat sink area. They also have a power monitor display using a light emitting diode array and in the case of the 1801 signal meters as well.
DISASSEMBLY/ASSEMBLY PROCEDURES 1801 Power Amplifier Note: Refer to Figure 1 for the following 4.3 Connect the wire harness, thermal procedures. cutout wires, and the input cable to the PCB. 1. Top Cover Removal 5. Front Panel Removal 1.1 Remove the two screws that secure 5.1 Perform procedure 1.
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DISASSEMBLY/ASSEMBLY PROCEDURES 1801 Power Amplifier Note: Refer to Figure 5 for the following 12.2 Place the meter lamp housing over procedures. the meters and secure it to the front assem- 9. LED PCB Removal bly. 9.1 Perform procedure 7. 12.3 Perform procedure 8.
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DISASSEMBLY/ASSEMBLY PROCEDURES 1800 Power Amplifier Note: Refer to Figure 1 for the following 5. Front Panel Removal procedures. 5.1 Perform procedure 1. 1. Top Cover Removal 5.2 Locate and remove the eight screws holding the front panel to the chassis. Four 1.1 Remove the four screws that secure of the screws are located just inside the the top cover to the unit.
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DISASSEMBLY/ASSEMBLY PROCEDURES 1800 Power Amplifier Note: Refer to Figure 6 for the following Note: Refer to Figures 3, and 4 for the following procedures. procedures. 9. Gain Control Removal 13. Rear Panel Removal 9.1 Perform procedure 5. 13.1 Perform procedure 1. 9.2 Remove the gain control knobs.
C4. 4.2 Apply a 1.75Vrms, 1kHz signal to the Note: The 1801 and very early 1800's had input. two lugs on the caps. One with two or three wires and one single wire. The later pro- 4.3 Turn the gain controls up to the point...
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.
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PART LIST Main Part List (per figures 1-7) Item Description Part Note Number Number Rubber Foot 121929 Fuse (110v)15A, 1 1/4 x 1/4Slo-Blo 103608 Fuse (220v) 8A, 5 x 20mm 108190-800 Fuse (220v) 7A, 1 1/4 x 1/4Slo-Blo 103609 ¥ Fuse Cap for 1 1/4 x 1/4 109484 ¥...
TROUBLESHOOTING GUIDE S Y M P T O M POSSIBLE CAUSE 1. DC Offset: ≤2v Defective U1 Defective Q1 ≥2v Test point "A" polarity Defective U1 Defective CR1, 2, 6, 15 the same as DC offset Open ground at the RCA (see Figure 11) input jack Defective Q1-8, Q24...
2. Refer to the figures below for the voltage conversion being performed. 3. On the 1801 when converting to 110 volts remove the in-line resistor found wired to the thermal cutoff indicator. Connect the wire directly. For 220 voltage conversion connect a 56k ohm 1/2 Watt resistor directly to the thermal cutoff indicator terminal.
1800 Amplifier used with a TC-18 Transit Case. Remarks: The 1801 power amplifier board ( part # 102735 ) will no longer be shipped as a standard repair part. Instead, a universal replacement board ( part # 102735-1 ) with a special thermo- static clip connection allowing the use of this board in the 1801 and early production 1800 wire harness assembly.
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Bulletin #13A Remarks: We have found that the resistor R3 on the 1801/1800 amplifier PCB's have shown a higher failure rate than normal. Studies reveal that the resistor normally runs at about 150-170°F. The etch layout at R3 is not sufficient to provide adequate heat sink for this component, and the resistor eventually changes value due to the heat.
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SERVICE BULLETIN Subject: Thermal Improvement Date 10/05/1979 Bulletin #17 Remarks: I'm pleased to inform you that we have developed a method for improving the thermal stability of the 1800 amplifier, which may have been a problem to you during the last several months. This problem was caused by a change we were forced to make when RCA discontinued the manufacture of the transistor we had been using as Q3 on the 1800 PCB's.
1800 amplifier boards currently being produced. The transistors have been change from Bose P/N 102433 (2N5840) to P/N 117579 ( Motorola MJ15011). The new output transis- tors are not compatible with the original 102433 transistors. If you service an 1800 power amplifier or PM-2 mixer, check the serial numbers on the printed circuit board and the P/N on the output transistors to see which output device is being used.
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SPECIFICATIONS AND FEATURES SUBJECT TO CHANGE WITHOUT NOTICE ® ® Bose Corporation The Mountain Framingham Massachusetts USA 01701 P/N 192527 REV. 01 06/97 FOR TECHNICAL ASSISTANCE OR PART ORDERS, CALL 1-800-367-4008...
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