Peavey CS800C main filter cap change

[Axerob]

My Cs800C is in dire need of a main filter cap change. I have checked it out, and see no easy way to do it, so my question is...What is the least difficult way to go about this? Thanks in advance.

[Jazz P Bass]

Welcome to the Forum.

This is a no BS site so take this lightly.

One question: what makes you believe the main filter capacitors are faulty.

If you measure undo ripple across the positive &/ or negative power supplies, that is a good sign that something is amiss.
As it may lead one to the conclusion that the capacitors are at fault, it does not prove it.
Only further troubleshooting can lead to a verification.

I have worked on a ton of these amps & I have not replaced one of these capacitors.
The things are huge!
That does not mean that you do not have an issue, far from it.

Here is a pic of the chassis with the two power amplifier assemblies removed.
The filter capacitors are on the right.

[Enzo]

Hi Axerob, welcome to the place.

I agree with Jazz. I have been an authorized Peavey servicer for the last 29 years, and I have repaired many of these popular amps. And I too have never had to replace one of those caps. Not to say one couldn't fail, but I haven't seen it.

Just a guess: if you get a LOUD hum out one of the speaker jacks, that is more likely to be a blown amp channel than a bad cap.

Note in the photo above, the two amp circuit modules have been disconnected, and set aside. Under each of those two large modules is a four-wire connector. Unplug that and that channel is out of the way electrically. If you then power up the amp with the modules disconnected, you can measure ripple on the two caps to see if they are working.


But to answer your question, if I did have to replace a cap, I would loosen the mounting clamp and slide the cap towards the transformer, and out of the clamp. If there is not enough room for that, then unbolt the transformer and move it aside enough to clear, or drill out the rivets holding the clamp. A quick look in Mouser found me some 15,000uf 100v caps with screw terminals. I did not check dimension, but they are probably smaller than the old caps, and so would have to have some changes made to the clamp or other mounting arrangement. But if you look at other supliers you may well find even smaller 15000uf caps in a snap-in or wire lead package. ALl would work well, just figure out a mounting arrangement.

But really, be DARN sure you need a cap first.

[Jazz P Bass]

Average cost will be anywhere from 40 to 80 dollars.
For 1.
Your mileage may vary.

[Mick Bailey]

Sometimes the screw connections can come slightly loose and the terminal oxidise slightly (especially if the amp is kept in condensing or damp conditions). Even when the screws are subsequently tightened down there can still be some resistance. It's worthwhile checking the integrity of the connections.