I need to assemble (build) a circuit to test the AN7164 audio amplifier

[jfminformatica]

I have a Philips AS667C sound that I can not turn the unit on, only the display flashes ("- -"). A source voltage that should be supplying -43V is supplying -33v that sits on transistor 7261 (BD238). The standby is inoperative. The voltage at pin 6 of the AN7164 is low, it is supplying below 4.4V.

 

[BradtheRad]

The subnormal volt levels suggest:
* fault in power supply,
and/or
* short circuit wasting power.

* Look for fuses or circuit breakers. Test them for continuity.

* Measure power supply voltage levels. If low then check all diodes. Each should have a wire clipped so you can test out of circuit. Solder the wire later.

* Do you have an oscilloscope? Massive ripple on power supplies suggest you have a faulty diode in the supply.

* Examine all capacitors for bulges, leaks, burnt appearance, powder deposits, etc.

* Was the unit dropped? Examine solder joints for fractures, loosened components, etc.

* Don't hook up valuable speakers while you troubleshoot, but attach resistors to power amplifier to act as some load for safety. Do you have power resistors, say 10 ohm? Or can you combine resistors?

* Listen through headphones in case sound is slightly amplifed.

The above tips are merely obvious things to try. One of them may provide a clue to a path which is worth further exploration.