Peavey cs1000x transistor equivalents

[retgaz]

Hi,
I'm repairing an old Peavey CS1000x. It's got a lot of shorted output transistors. The two drivers have Peavey numbers: 70481180 and 70471180. They look like they've survived. The output transistors are MJ21193 matched with a mix of MJ15024 and 70483180 (seemed a strange mix to me).
So four questions:
1. Does anybody have a table of equivalent transistors for Peavey transistor numbers.
2. Does anybody know what transistor numbers the MJ21193 have replaced.
3. What transistors should I be using for the output transistors on this amp?
4. Is there anything else worth checking/ servicing while I'm in the amp. (The triac on the output is ok)
Thanks in advance for any help anyone can give.
Gaz

[Enzo]

I know I have put it up before, but here is the Peavey guide. They would send it to you upon request anyway. As they will any schematics.

On most of the Peavey power amps, they don;t tend to burn very far back into the circuits. OK drivers is a good sign. ALWAYS check every resistor involved.

The PV transistors are Motorolas, (Now: ON Semi) Those 704xxxxx numbers are PV part numbers for them.

Look at the schematic. The V+ side output transistors are 8332, short for SJ8332. That is the old style part number. They now call that a 70483180. The street part number would be MJ15024, NPN 250v 16A 250w. You may find those mixed on there, as they are the same part.

The V- side uses 8333, now 70473180, or MJ15025. PNP.

You can order the 704xxxx types from PV direct, or just buy the MJ150xx from Mouser or Allied or someplace. Those are the parts specified in the schematic. There is no availability problem, the cost is not out of line (and you won;t find something else significantly cheaper), so just put the right parts in there.

The MJ15024/25 pair (NPN/PNP) are some of my favorite transistors. Motorola/ON has a newer part, the MJ21194/93 (NPN/PNP) with the same basic specs. They are functionally equivalent to the 15xxx ones, and you can probably mix them in with the others. I recommend not to though. They are similar in specs, but they are made by different technologies, so I am not necessarily confident they will track thermally or share current equally. I am probably being way over cautious, but these are high power amps and such things matter. SO a row of MJ15024 OR a row of MJ21194, but I prefer not a mixture. Same deal with the MJ15025 vs MJ21193.

Having said that, I don;t care if the one V+ side uses MJ15024 and the V-side the MJ21193. That is opposing sides, not sharing side by side.

But on the whole these amps are remarkably flexible as to what to put into them

[retgaz]

Hi Enzo
Thanks for the help. You covered everything I needed and more.
I hadn't found the Peavey guide when I was searching the forum. I'll keep a copy for future work on Peavey gear.
I haven't got a copy of the schematic for this amp, but I've got one for the cs1200x which seems similar. The damage doesn't seem too bad, so I won't worry about the correct schematic unless I find any other problems.
Thanks again
Gaz

[Enzo]

The other drawing may be close enough to get you going, but for the cost of a free email, why not get the right one also, and then you will have it for when the differences DO matter.

[Steve Conner]

I've put the Peavey transistor cross-reference as a sticky in the Schematic Requests forum, hopefully that'll make it easier to find.

These old Peavey amps are pretty solid. Just stick in some new transistors and give the bolt through its neck a twist.

[Spudler]

Awesome Thread. BTW I am curious as to what the Serial # of you CS1000X was? I just got one not long ago with the exact same Issue looks like somone attempted to repair it a while back but I was told by the Local Peavey Authorized Service Center that all 12 Transistors were blown but not a single Resistor was bad. As A matter of fact teh quote and info I recieved on teh amp to repair it claims that teh only thing wrong was the Tranisistors on Channel B all 12 5 of the MJ15024 5 of the MJ15025 1 of the MJ15020 and 1 of the MJ15021.
Has anyone else ever heard of this? All 12 Transistors blowing but not one single other thing?
Not only that they quoted the cost to be $120 for parts, I just found all of them for $23.95 how could they come up with such a overinflated amount for these?
I recently just downloaded the Specs PDF for the Transistors and was curious as my Meter only displays the hFE Value will that tell me if teh transistors are OK or Bad? I want to double check to make sure they werent just planning on changing all of them if one may have been bad.
I seen you mentioned not to mix andmatch and I was curious all of the Transistors currently on the B channel are all 704**** #'s but I purchased MJ150** #'s Should I plan to replace all of them whether or not they are bad or would it be fine just to replace the bad ones as I believe the 704**** and the MJ150 are exact same Items just different #'s
I decided to attempt to repair this CS1000X myseolf because the quote I got was for $385 like I stated $120 for parts and $260 for labor.
I can find another one in working oreder on ebay for less then the quoted repair cost and I have actually seen 2 sell for less one was about #250 and one was $299.

[Enzo]

Hi SPudler, nice to see you found this forum.

The PV 704 #s are made by Motorola/On-Semi, so the MJ series Moto transistors are the same thing as their 704 cross types. You can mix 70483180 and MJ15024 if you like. Don't mix in NTE crap or something else.

And when we talk of not mixing, we don;t mean channel to channel. You could have all Motorola in channel A and all RCA in channel B if you wanted. Not only that, we mean all the same on each polarity. SO you could conceivably have a row of PNP Motos and a row of NPN RCAs.


Transistor failures can be from many causes. If one shorts collector to emitter, it will usually blow the fuse, but it will also stress the other side, so typically you get one on each polarity. But when a transistor shorts from collector to base, it usually takes out the whole row of them. And that also stresse the other side, so you might find all the NPNs bad and one bad PNP, or all the PNP bad and one bad NPN.


I just checked all the major suppliers I might use for MJ15024. Mouser, Allied, Digikey, Newark. I trust I will get real parts from them, I run a professionashop. There is a serious problem in the parts market of fake transistors. I NEVER buy parts on ebay. I found all those suppliers selling MJ15024 at from $4 to $4.50, with one at even a bit over $7. Each. If you found a dozen of them for less than $2 each, I hope you don;t get counterfeits.

Repair shops are in business, they don't and can't sell you parts at cost. For small items like transistors, shops often use the "A markup" or basically twice cost. SO if I buy transistors for $4, I sell them for $8. If I order 12 MJ15024 at $4, and add $12 shipping and handling, my cost is $48 plus the $12, or $60. DOuble that and I am at $120. I would imagine that is exactly how your local shop came up with that amount.

Can those transistors fail and not burn up their resistors? Certainly. They often do burn resistors, but it is not a requirement.

Checking transistors. I never bother with the gain, though it probably can illuminate some problems. I use the diode test fuinction o fmy meter to look for shorted ones. In my experience, thatis usually sufficient to find the bad ones.


$260 sounds a little high for labor on the surface, but I don't know what your local labor rates are. I charge $60 an hour here. But in fairness, we can;t after the fact look at the parts list and say since it is just those transistors and nothing else, that they should be done in ten minutes. You have time into tearing it down and reassembling the unit. They have to determine what is wrong, and impoortantly, what is not wrong. How long does it take to go through the entire circuit making sure transistors are not blown and resistors are not open?

I just went over to PV and reread your thread. They quoted three hours labor? And the anp also had the turn on triac issue and some board damage? I know you don't like paying out $$$, neither do I, but is three hours for the whole job excessive?

[engelheimer]

My question is a good place to buy the MJ15024/25.

Had luck with the vendor i've used in the past, usually buy 10 of each and cull from these.

My last order all the PNP's were all in the 90's, sent e'm all back. Ordered from Peavy yesterday, am thinking of giving Mouser a try.

Seems to me there should be a place to order these in matched pairs/quads/octos etc...

[Enzo]

peavey doesn't match them, their circuits are not that sensitive. I have bought my Moto transistors from Mouser for years, though for a whle I did use Allied a lot for them.

[engelheimer]

POT

I like Mouser, might try Allied, Thanks!

peavey doesn't match them, their circuits are not that sensitive. I have bought my Moto transistors from Mouser for years, though for a whle I did use Allied a lot for them.