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Framingham, MA 01701-9168 SIZE
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199747-TT SHEET
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Troubleshooting Tips
Model 1800V and 1600/1800 VI Amplifiers
Refer to the Model 1800V or 1600/1800 VI Amplifier service manual, reference number 181812
(1800 V) or 199747 (1600/1800 VI) for schematics, PCB layouts and parts lists located on the
Pro Products page of the Bose Service web site at http://intranet.bose.com/tsg
or
http://serviceops.bose.com.
Preventative Repair Measures
Note: Perform the following on all units returned for repair.
Product Check Action
1800V
1600/1800 VI There are no preventative measures to perform on these
amplifiers.
Troubleshooting Tips
Product Symptom Check Action
1800V
1600/1800 VI Dead unit Fuse 1. Verify that fuse F1 located on the front
panel is good. Verify that it is the correct
value for the AC line voltage version of the
product.
2. Check for +/-15VDC on the power supply
PCB. Check R6, R7, R8, Q2, Q3, D3, D6.
1800V
1600/1800 VI Blows main fuse F1 at
turn-on. Output power
transistors Check that the output transistors are not
shorted internally or shorted to the heatsink.
1800V
1600/1800 VI Dead unit Fuse 1. Verify that fuse F1 located on the front
panel is good. Verify that it is the correct
value for the AC line voltage version of the
product.
2. Check for +/-15VDC on the power supply
PCB. Check R6, R7, R8, Q2, Q3, D3, D6.
1800V
1600/1800 VI - Dead unit
- No Sound
- No front panel LEDs
lit.
- Unit drawing too much
current at turn-on. Power supply
MOSFETs. 1. Check that the output transistors are not
shorted internally or shorted to the heatsink.
2. Check Q9, Q14, D13, D19, Q20 and Q25.
3. Check for the low voltage rail +/-53V at the
outputs of D13 and D19, and the high
voltage rail +/-106V at Q14 Source and Q25
Source.
1800V
1600/1800 VI No audio output from
one or both channels. Output relays. 1. Check output relays K100, K200 and
associated circuitry. Check for VLF+ voltage
at pin 6 of the relays (+24V).
2. Check U1 on the Input/Output PCB.
1800V
1600/1800 VI Audio cuts out,
intermittent. Input level
controls Check potentiometers R101 and R102 for
proper operation. Clean or replace as
needed.
1800V
1600/1800 VI Unit keeps going into
protect mode. - Input module
PCB diodes.
- Power supply
board 15V
regulator parts. 1. Check the diodes tied to the +/-15V lines
on the input module PCB; D7, D8, D9, D10,
D15, D16, D17, D18, D20 and D21.
2. Check the transistors, diodes and resistors
for the +/-15V on the power supply board,
R5, R6, D3, Q2, R8, R9, D6 and Q3.
Page 2
Framingham, MA 01701-9168 SIZE
A FSCM
32108 CLASS
FM DWG NO.
199747-TT SHEET
3 of 3
REV.
00
Product Symptom Check Action
1800V
1600/1800 VI Amplifier Sequence
function not working. Input Module
PCB. Check the input module PCBs remote
power-up circuitry. The input comes into the
amp at J3 pins 1 and 2 and goes through
Q1, Q2, Q3 and the associated components.
Check for shorted or open parts.
1800V
1600/1800 VI All - Perform the steps in the 1600/1800 amplifier
Troubleshooting Guide, 199747-TG1 located
on the Bose Service web site.
