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Zero Cool 15th October 2004 03:59 AM

Peavey CS-400 Schematics Wanted
Peavey CS-400 Schematics Wanted.

Anyone know where i can find some peavey CS-400 schematics online???

Zero :cool:

dangus 15th October 2004 04:52 AM

No, but Peavey could send you some:
Owners manuals and schematics, not available on the website, may be obtained by mail (via check or money order) or by phone (via credit card). Schematics are $2.50 per copy, owners manuals are $7.50 (paper back) / $20.00 (notebook). Send Check/Money order to: Peavey Electronics, Parts Department, PO Box 412 Hwy 11 and 80, Meridian, MS 39301. Credit Card orders phone: (601) 483-5365. This applies to US and Canadian residents only. Outside the US or Canada please contact your nearest Peavey distributor.

Enzo 15th October 2004 05:36 AM

Peavey has the best support in the music biz. You can call them or get on the parts forum at the web site. But you can also just email them at And if you need advice, the repair forum there gets you right to a factory service tech. Um, and me.

Include the serial number, and look on the serial number plate for the official model name. Ther have been a couple version of CS400.

If there is a blown output channel it is almost always a couple shorted output transistors. Each channel has its own power connector to the output module, so you can unplug each one to find whuch channel is blowing you r fuse.

Do not mix output transistors. if they are Motorola house number parts, get more from the factory. They charge reasonable. DO NOT use NTE. Mixed transistors will not share current well.

If they are the obsolete RCA ones, you may have to replace the row of them.

Zero Cool 15th October 2004 05:39 AM


I have 2 of these ******s to work on and some other odd mono amp to work on. not sure of all the problems, one has lots of DC on the speaker output so im sure there are blown outputs there...the other one i think he said has some sort of white noise problem then blows the fuse?????

I will start tearing into these this weekend.

Zero :cool:

Zero Cool 15th October 2004 05:40 AM

P.S. I NEVER use NTE/ECG parts for audio stuff... Old pinball machines sure....amps no way!


Zero Cool 19th October 2004 05:17 AM

OK, i managed to get one of these beast's running out of the 2!

So, so far i know i need the following parts:

6x Motorola SJ6357
2x Motorola SJ6344
1x RCA 70487478 (or is it 704B747B?) Compressor IC

Plus some Misc Resistors etc.....

Zero :cool:

Netlist 19th October 2004 07:20 AM

Did you take the TO3's out to measure them? I guess you did ;)

The DDT IC is 70487478. As far as I know, there is no replacement part.
You can find the with Google or at Peavey.

P.S. : Don't forget to check the output coils for bad solderings.

Good luck

/Hugo :)

Zero Cool 19th October 2004 04:26 PM

I pulled all the TO-3's out and 4 of the 6 outputs were bad and one driver was bad. so im replacing all of them so there close to matched....

I yanked parts from the other CS-400 i need to fix and got both sides working, but the DDT IC was still bad, once i figured that out it came alive and seems to be running. now to fix the cannibalized one and get them both back on the road!

Yes i noticed the output coil is pretty weak. I will use some heavy silicone to try and hold that in place a bit better.

These things are horrible amplifiers by audiophile standards! Yuck, but there brutes and they work. and the DDT actually works pretty well by my scope! you can just start to detect a hint of clip when the DDT kicks in. the LED is a bit slow to respond, but it does work to keep the amp out of hard clip!

Zero :cool:

Enzo 20th October 2004 02:43 AM

It is designed to be a rugged and reliable power amp for live sound. Yeah, it would not be the choice for home stereo. The DDT works well, we never want clip.

Make sure none of the cement resistors are open.

The 478 can be left out for amp testing, you just won't get any DDT limiting. It is a CA3094.

The SJ numbers are house numbers. Ther are newer house numbers and then the generic equivalent.
SJ6357 = 70484140 = MJ15003
SJ6344 = 70481180 = MJ13330

You could just replace the drivers with MJ15003s as well. And since all of them are being replaced at once, you could even move up to MJ15024s all around. Just don't mix types. Even MJ15003 and 15024 have different internal contruction and won;'t share well. Pick one type and fill it up.

Peavey has a master cross reference for semiconductors, you can get it from the parts department there. Peavey will sell you parts directly and they are not unreasonable prices.

I use a lot of the MJ series power xstrs, and I buy them from Allied. Big MJs are about $2.50 each Expect close to $5 elsewhere.

WARNING. Peavey uses a crowbar across the speaker terminals. if the amp is blown up, ther is a good possibility the crowbar is shorted. Unless your amp is too old to have it. Th A series does not have it and the B series does. Just measure across the speaker terminals. If it is a dead short, the SAC187 triac is shorted. The little gate drive part is almost never bad. it is located on the board with the speaker posts, not up on the power amp card. So even with the power module disconnected, the short remains.

The crowbar detects DC on the output line and when it does, it turns on and shorts across the output. The part usually gives its life in the process, but it keeps your speakers from catching fire.

You can get parts and schematics for all Peavey stuff by contacting the parts department. Call 601-483-5365 and ask for parts or email Don't forget the cross reference, it lists all the generics for the house numbers.

Zero Cool 20th October 2004 05:21 AM


Thanks for the info! I sent an email to the Peavey Parts department and Hope sent me a very nice reply with part numbers and prices! I will be ordering parts soon!

Both the amps i have are too old to have the crowbar!

But, I have an old CS-800 on its way to be fixed! It seems once word got out i can fix Peavey amps, everybody and there brother started digging them out of the closet, garage, shed, basement, and band rooms~!~ hahahhah I think the folks over at Peavey and i will be getting to know each other well!!!

P.S. True Peavey Story, I know a guy in Dallas Tx that has a stretch Limo Van with 40, thats right 40, 15" woofers wired up to 5 Peavey CS-800 Power amps and 12 car batteries wired to provide +/- 70VDC for the amps!!! He runs the van in car stereo volume competitions!!! Crazy Stuff!!!

Zero :cool:

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