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A guy brought in a Peavey CS-800, that outside of the normal shorted outputs and cold solder joints - also had some other hidden treasures for posterity.
While checking for shorted and open components on the "B" channel power board, I found that not only was R21 open, but right next to it - R1 had never been soldered from the factory. The lead was broke off just in the right place to make the tiniest bit of contact with the PCB trace, but had absolutely no signs of ever being soldered, by machine or by man.
Before repairing these - my dim bulb acted kinda like a strobe... it would come on bright, the caps would charge and drain it down, then it would start pulsing about twice per second.
It only did it with a driver board connected, and lifting the ground at the zener board (from the triac harness), or pulling the main power connector for that power board, would make it stop.
The picture was taken before removing R1.
While checking for shorted and open components on the "B" channel power board, I found that not only was R21 open, but right next to it - R1 had never been soldered from the factory. The lead was broke off just in the right place to make the tiniest bit of contact with the PCB trace, but had absolutely no signs of ever being soldered, by machine or by man.
Before repairing these - my dim bulb acted kinda like a strobe... it would come on bright, the caps would charge and drain it down, then it would start pulsing about twice per second.
It only did it with a driver board connected, and lifting the ground at the zener board (from the triac harness), or pulling the main power connector for that power board, would make it stop.
The picture was taken before removing R1.
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