Peavey Powered Mixer/Wierd Problem

[jcollins]

So my buddies Peavey powered mixer has this strange problem.

To get it working, after it's been turned on, he has to turn the volumes up
a bit, with no speakers attached, and run a signal through it.

Then it "wakes up". If he doesn't do that, no signal will come out of connected
speakers.

Once he does that the PA works fine.

Any ideas what could cause this?

[Jazz P Bass]

Dirty contacts on the power amp in jacks would do it.
Try going in the jacks at power up.
If you have immediate signal, there you go.
They need cleaning.
This type of test can also narrow down the problem to preamp or poweramp.

[Ronsonic]

"Break through" things like that are almost always either dirty conx, like the "Power Amp In" jack just mentioned, or a failed op-amp.

Always check looping jacks first, all the inserts, out and ins, FX. Easiest test is to use a cable between the out and in and see if it works better.