I suspect you have a fault condition that's causing the relay to be triggered. Check the inputs of each comparator to see which one is indicating a fault and go from there.

 

What happens if you bypass the relay contacts, does the amp work then?

 

What happens if you bypass the relay contacts, does the amp work then?

If the OP does this, he should understand that defeating the fault protection circuitry could have negative consequences.

 

Hello,

As mentioned there are a couple of conditions that can be checked.
1) the temperature.
2) DC on output.
3) short on output.

Bertus

 

Whats voltage is on pin 1 of U5a, and whats on the relay contacts?

 

The voltage on pin 1 is -13.67 volts. I would assume that verifies that there is no short which there is not. The output transistors seem fine. The voltages are correct and there are no shorts. However the relay is still pulsing which is shown in the attached waveform in a previous post. I am going to try to heat the heat sink with a dryer to see if that changes anything.

 

I heated the area on top of q132 and q232. That slowed the pulsing down and as it cooled it stopped pulsing. I guess that means one of these devices could be the culprit?

 

The input on pin 2 of U5 is +13.6 volts. Not sure if that info helps.

 

.

 

Hello,

Q132 is an 8 Volts diac.
From the service manual:



The circuit with Q132 is connected to the output of the amplifier, to detect DC:



Bertus

 

I removed both the triacs and C144, C244 with no change. Immediately on power on still relay clicking. I put a 10 uf cap in parallel with c121 and that reduced the clicking considerably but did not stop it.

 

Found the real issue. There was a bad trace under relay K100 leading to pin 1 and 2 of U104. Looks like it was water damage. Moisture built up under the relay and corroded the trace. Just wanted to let everyone know and thank everyone who tried to help.