Needing help repairing an Orion HCCA 250 Digital Reference

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The muting circuit on this amp is similar to the HCCA 225 but different. I pulled the other 2N5639 that is part of that circuit and checked it. It is fine. Also checked the voltage on pad 3 of the two muting transistors, voltage is -15.5v. Any idea of what else I should check?
 
That is my fault as I failed to state that I had reinstalled them after I pulled them in the beginning of this thread. I had actually reinstalled them before I started it. Sorry about that.


To be honest I'm not sure if the the input to the 5534 was constant as I'm not sure if I ever tested it after the amp output had fallen off.
 
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To get on the same page...

Post images of the waveforms on the two inputs and the output of the 5534 just before and just after the output clips. 6 images.

If the speaker output is still clipping at 10v and the rails are still well above 10v (30+v), there's no need to post photos of the output to the speaker terminals.
 
Scope set at 5v/div.
The photos are of the 5534 input pins 2 and 3 and output pin 6 left to right.
First 3 are just prior to clipping, second 3 are just after clipping.
 

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Non-bridging speaker wires are the wires that are not used when the amp is connected in bridged configuration. They go into the center of the board.

Also check the resistance from the RCA shield to the secondary center tap on the transformer.

Do you have a current limiting resistor or dummy load?
 
Yes, I have a current limiting resistor I can use. As soon as my scope warms up I'll run that test.


The resistance between the RCA shields and the non-bridging speaker wires is 0.1 Ohms (my test leads are 0.1 Ohms).


Will you show me the the secondary center tap on the transformer?
 
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