Troubleshooting Powered Mixer

[Jazz P Bass]

Blown output setcion

Please stop turning on the amp with a speaker or any load.
Get your power supply straightened out first.
Remove all the output transistors. Check for short condition.
There are transistors in the output section that are right before the output transistors. They are called the drivers.
If the output ICs are shorted, replace the drivers also.
Check the bias transistor for a short.
Better yet, replace it.
See how the failure is working it's way back.
You can't check enough.
When you do get around to turning the amp back on, it would be nice to have a variac, a lamp limiter & (2) good voltage meters.
One meter to watch the B+ B- Vdc & another to monitor the output for unwanted Vdc.
Sometimes when a power amp output section goes bad, it can get ugly.
I guess the object is to make it pretty again.

[captntasty]

I have checked the output transistors and one was blown - I replaced it. I will check the drivers tomorrow. Weird thing is I was checking the +15v rail with no load and it sort of righted itself. I did hook a speaker up (one that I don't mind cooking) and well, it works - the LED display is normal, I get signal all the way through, it sounds OK... I know it probably means that there are still problem components that may be working intermittently. Until tomorrow...

[captntasty]

Driver transistors are good. Still a little weirdness on the +/-15v rails. -15v reads 14.7v but the +15v reads 13.2v - I had already replaced the 7815 positive regulator. Could caps c3,4,5,6 right before and after the V regulator be a problem?

The Peak LED is still constantly lit. What can I check on IC1/LM339 which is associated with peak limiter? IC2/TL072 has already been replaced - it was NG.