peavey cs-800c

[tcs30]

hi i hope i can get some help here? i have a cs-800c amp, and the first thing that happened to it is that it lost channel "b" it quit working and the red led light for clip stayed on solid, channel "a" still worked. now i had one of these amps before that did the same thing and it was one of the 15000mfd caps inside that went bad i replaced it, and channel worked again. now for this amp that i have now, i must have done somthing wrong when i pulled the caps to check them.

1. i pulled the caps and discharged them so i could check them with a dmm which is all i have to check them with. both of them went from 0 ohms and kept going up, so that means they are taking a charge, they didn't stay at 0 or anything. then i tried 3 volts dc current to them to see if they would hold that charge, and they did, so i guess they are fine.

2. put caps back in and wired it see attachment

3. turned it on and it blew the fuse. it should have came on with b channel still not working and a channel working.

i don't know what went wrong. so i started disconnecting wires from the caps.

disconnected the white w/ green stripe wire first, still blew the fuse
disconnected the yellow wire that goes from the cap to the b channel heat sink board, and it stopped blowing the fuse, but the front cap started getting hot quick, i herd the inside of it pop before i turned it of. i'm a novice at this stuff, and yes i should hsve never messed with it, any help would be appricated.

[Enzo]

Glad you made it.

Elsewhere I mentioned that the large caps would not usually cause a problem in one channel only, since they are shared by both. But too late now.

I would bet my lunch money you got one of the caps wired backwards, at least temporarily. And it may be damaged.

Look at the four red wires and the four yellow wires. One each to each power amp module, one each to the main bridge rectifier, and I forget where the other would go, down to the zener board probably. Find the wires from the main bridge rectifier. Isolate those wires. Of the several "ground" wires, find the one from the power transformer. It may have cloth insulation (or not). Isolate that. Connect your DC meter ground to that center tap wire and power the amp. Check that positive and negative DC are coming from the bridge rectifier. it will measure lower than normal because ther are no filters connected.

Power off

If that is good, look at your caps. check that neither is now shorted. Install the shorting bar between, and be careful to verify one - and one + are shorted together. Connect that transformer center tap wire to the bar under a screw. COnnect the (presumably red) wire from the bridge + to the free + cap terminal. Power on. IS ther now +80VDC more or less across that cap?

Power off, and careful, since there is nothing across that cap to drain it, it can hold that 80v charge for a long time.

Conect the (presumably yellow) wire from the - of the bridge to the free - cap terminal, and power on. Does -80v appear now across that cap?

If the caps both charge up and sit there, we can move on, but if there is a problem just getting that far, we have to solve it before moving ANY further.

However, at this point we can probably connect the rest of the ground wires. There should be a wire out to each speaker terminal ground, and one to chassis I think.

If all that sorts out, check the diodes on the little zener board on th floor inside the amp. ANy shorted? leave the four pin molex connectors off the two powr modules for now, but you can connect the power supply wires from them back to the caps. REmember to check for retained volttage. And connect the power supply wires from the conector on the zener board.

Power on without the modules connected. We now should have a complete power supply running.

Power off, and you should be able to connect the power modules, and then we are back to chasing the original problem.