TOA P2122 Schematic?

[tim]

Hey all,

I have a TOA P2122 here on the bench...it pops through the speakers when turned on...it appears that the turn on muting circuit isn't working anymore. Does anyone have or know where I might get a schematic for one of these? I use to have one but when I moved, I must've misplaced it. I can't seem to find it anywhere. Here's to hoping...

Thanks!

[Enzo]

Did you ask TOA?

Mute? Hard to say. Unless it is a speaker relay, a mute circuit can only do so much A lot of amps have a mute at the power amp input. But that will have zero effect on noise generated within the power amp.

[tim]

Hi Enzo,

Yes and they don't have anything....this belongs to a school and is one of several of the same model. On the good ones, there is a red LED that comes on immediately as soon as it's turned on and then after a couple of seconds, the LED turns green (and no pop). This one, the LED goes to green immediately and pops. Maybe I can reverse engineer the circuit, following the LED back to the circuit. I suspect it's a RC circuit that is supposed to turn on (or off) a muting FET somewhere once the DC supplies have settled out and one of the components has failed. Other than the power on mute circuit, the amp works as advertised. It's no hurry...I have all summer to get it fixed...