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kevin6878 5th February 2019 04:23 AM

Need schematic for cs800 but not s or x. Looks like the x one.
3 Attachment(s)
Hello all im new to this forum to join but have read alot learned alot.Thanks . New problem i have is a Peavey cs-800 3u just like the cs800x but no x denoted. I need a schematic because it has a few shorted output xsistors.A shorted triac,the power on triac and a shorted bridge rectifier. Theres so many different cs800 models and its hard to get the right infobill post a pic here of it. Thanks if anyone can email me the right schematic.I have not heard back from peavey.Let me know if i show my email here if any of you fellas have it to send

Enzo 5th February 2019 04:52 AM

Use the CS800X. The difference between the X and non-X versions is only on the spec sheet. The X was added when they tested the amps and felt they could safely rate them down to a lower impedance load. The circuits are identical.

PV is usually very responsive, but you are in the USA, and as always, a phone call is the most effective. Most guys who call report it takes about 10 minutes for the files to arrive.

If you do communicate with them, call this a "wind tunnel" version.

indianajo 5th February 2019 12:02 PM

The schematic is also available 24/7 on
Search cs800x. You don't have to be a member.
The output transistors are MJ15024/25, but if you replace them all you can use cheaper MJ21193/94. Don't forget to check the emitter resistors.
The drivers also are usually blown out by the current out the base line of the outputs. You can use mje15032/33.
The predrivers can be MPSA06/56 or MPS8099/8599.
The triac is generic, I used a 600 v rated one for the on/off one. BTB16-600cw. The sense "sbs" on the crowbar circuit blows sometimes, I use the powerex bd08s from newark farnell. They sometimes have J174 DDT transistor but nobody has the ca3080 transconductance amp IC.

kevin6878 5th February 2019 05:29 PM

thanks so far i have two xsistors shorted the 70773180 ones ,are they the pnp or npn?
i have a shorted pre driver number je350 what do i use for that again?
and the triac is shorted on one channel the sac187.
Im new at working on the peavey .Thanks for any more help man.

kevin6878 5th February 2019 07:00 PM

i cannot find bd08s on farnell site .I searched the transistor category

kevin6878 5th February 2019 08:24 PM

it may not be worth fixing.I cant find a schematic that shows the diodes between some of the transistors.I have some of those bad too.The diodes that look like a lil loop between some of the transistors.

Enzo 5th February 2019 11:40 PM

Look for the dual diodes inside a little dashed line box. Like CR109? And three other diodes asociated.

Honest, CS800X is the right drawing.

Look at the schematic, 73180 are the PNP outputs.

It is an MJE350, not a je350.

SAC187 is a four quadrant triac. I forget what I used to use in place of them, but it was something common from Mouser. You can order them from Peavey, and they will send you whatever they use in their place.

If the SAC187 is shorted, just remove it. The amp will function without it while you continue repairs. We can replace it after the amp is working.

The big on/off triac is something like a Q4025 or Q4040. That is a 400v (or higher) and 25 amp or 40 amp.

kevin6878 6th February 2019 12:40 AM

ok thanks again ive been researching .I fixed a qsc 1400 but seemed less complicated.My mains triac seems ok it measures good but ill wait till last to see if it operates right..The items that are shorted are a je350 motorola #839 to126 that was on the heatsink .Standing up.There are 4.Also the sac187 and two 70473180 opts.Been checking other resistors ,seem ok.Btw im kind of a newbie.All i have is a hakko 951 and a ut33a dvom and an esr meter The old kit form ones.The dick smith one.
I,ll be studying the schem more guys.
By the way i thought this amp was quasi comp but it looks like the qsc,full complementary if im right.I need to build a DBT box but im low on funds lol.And no junk heater element layin around right now.By the way this peavey xformer could be used as an isolation transformer maybe.It outputs 115vac on secondary.When i tested it by itself.With 120v in on primary.

indianajo 6th February 2019 04:18 PM

The crowbar triac and predriver transistor part numbers are in post 3. If your supplier hates On semi, you can use 2n5401 and 5n5551 but they cost more for more Vcesus. The SBS (sac187) can be replaced by two 1.5 watt or bigger 7.5 v zeners back to back.
The little loop on the main heat sink is a dual diode, which may not read on some DVM if good. Drops 1300 mv. It's in a dotted line box on the schematic, and between pins 1 & 2 on the interboard connector on the power board. You can't buy them except from Peavey,and that takes a phone call and a long hold. You can use a red LED (10 ma or 20 ma kind) instead and insulate the lead that flys around because it points the wrong way. You'll need some heat sink compound on that heat sensor.
If it blew a predriver, the op amp may be toast too. 4580 is available at distributors from TI & NJR, but a 4558 will work if not sound quite as good.
Often the VI limiter and all its sense resistors and transistors blows up. That is the two transistors in the middle of all those caps & resistors right in the middle of all the drive lines. I'm not sure what it is good for when working, but will short out drive lines if it is all shorted. Some kind of old fashioned speaker protection for people that use megadeath crunch pedals (square waves) on their guitar. DDT backs off the high frequencies from those signals, too.
These cs800-x sound really good when working right. Even at 1/8 watt which is the base level sound in my living room. The one I bought also played a crowd of 300 in a parking lot, the previous owner told me. I fixed mine with a dvm, and an analog vom which shows music through the low level stages on the 20 vac and 2 vac scales. On an analog VOM you have to put a .047 uf (400 v) cap or similar in between the negative probe and the speaker ground, to make the AC scale not read on DC signals. You'll never catch an op amp whanging to rail because of a bad solder joint on the input, with a dual slope method DVM. They are too slow, they average the signal over a second or two and miss fast events.
BTW Peavey PA amps have a "flying ground" which means the speaker return has no reference to case ground or AC neutral. Has something to do with the bridge function, makes it cheaper. The Power supplies for the two channels are not related to each other, have separate speaker grounds that fly around separately. When debugging the circuit live, use the speaker ground terminal of the banana jacks for your reference.
I used a room heater element as my 120 vac ballast, 100 w bulb was too small to allow the +-16v to power up. Had nice spade lugs on it that matched the spade lugs on the power entry in the back. Room heaters are always blowing the tip over switch, lots of them in the garbage this time of year in the US.

kevin6878 6th February 2019 04:24 PM

Theres like 6 of those loops on the main heatsink.Are they all dual diodes.Thats one part that stumps me.On the schem locations it shows a normal diode symbol

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