U.S.AMPS 100HCA Power Supply Turns on 3 secs then looses Power

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No to both Questions ,The Amp drew only a small amount of current around two Amps.
The speakers didnt Pulse noticeably,The DCV on speaker leads measured this: One channel went to .5 volts on turn on.
the other went -.5 then +.5 when it turned off.
Note a little difference in the way the two channels acted is this a clue?
I took the measurement with an analog simpson Meter.
 
anyone have a schametic to this Amp ? A U.S.AMPS 100HCA ??
I have double checked all measurements they are accurate. On turn on the AMP draws 1.9 amps and slowly draws less till it its power LED fades out.
I am going to start Trouble shooting.
First I checked all output Transistors for unusual resistance measurments having found nothing there.
Next I am going to Fire it up again and take a IRThermometer and see if any of the componants change in Temp the amp has a Temp now of 81.3 degrees F some componants up to 81.9 for a starting temp..
 
I received the photos. This is a self oscillating power supply. It's much more difficult to troubleshoot than an IC driven power supply. Confirm that all of the passive components are within tolerance. If they are, I'd next replace the smaller transistors in the power supply. The larger capacitors aren't likely to be a problem but the smaller electrolytic caps should be checked.

It appears that 2 diodes are missing from the circuit board. Are they possibly on the bottom of the board?

Does it appear that someone has previously tried to repair this amp?
 
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