Verifying Audio - Toshiba 65HM167 - 65" Rear Projection TV Service Manual

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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