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Framingham, MA 01701-9168 SIZE
A FSCM
32108 CLASS
FM DWG NO.
172780-TT SHEET
2 of 2
REV.
01
Troubleshooting Tips
Bose
® BUILT-INvisible ® Amplifier
Refer to the Bose® BUILT-INvisible® Amplifier service manual, reference number 172780
for schematics, PCB layouts and parts lists located on service web site.
Preventative Repair Measures
Note: Perform the following on all units returned for repair.
Product Check Action
Built Invisible
Amplifier Replace all 100uF, 50V caps as
a precaution. The caps may
have leaked, causing damage to
the surrounding pcb etches and
components. Replace the following 100uF, 50V caps with new
components, part number 149948-101H.
PCB Number Ref Des
175466, 170015 C819, C822
174562 C26, C165, C166
170010 C16, C17,
170021 C107, C207, C307, C407
* Heat sink If a unit returned for service has a gold colored heat
sink, Polyimide tape should be added to the heat sink
to prevent the personality PCB from shorting to the
heat sink. This should be done even if the unit does
not exhibit the symptoms mentioned above. Refer to
service bulletin 172780-B1.
Troubleshooting Tips
Product Symptom Check Action
Built Invisible
Amplifier Dead F800, F801 and F802 Check for open fuses on the power supply
board. If one or more are open check for
shorted transistors on the amplifier pcb (See
tip below).
* Dead, blows
fuse when
powered on Power amplifier PCB Check the transistors that mount to the
heatsink assembly for shorts. Also check for
cold solder joints on the driver transistors.
