Toshiba 65HM167 - 65" Rear Projection TV, Service Manual

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Verifying Audio
Distorted audio can be approached using the drawing below and an oscilloscope,
signal tracer, or signal injector. Inputs to the Audio Output board can be scoped
on pins 2 and 6 of P860A or B. Signal injection and/or signal tracing can also be
applied to pins 2 and 6.
A missing audio symptom can be scoped at pins 2 and 6. DC voltage readings
can be taken at pins 8 and 9. The normal state of pins 8 and 9 are 0VDC.
Missing waveforms on pins 2 and 6 or a DC level on pins 8 or 9 will tell us the
Audio Output board is not at fault.
Pins 1 – 4 and pin 9 of PB81B or A can be checked for proper voltages to the
Audio Output board and
scoped for distortion causing ripple.
Pins 2 and 4 of P106 can be scoped for distortion. The grounds to be used are
pins 1 and 3, respectively.
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