Carver M400 Output Transistor Issue

Hello, and thanks for providing these forums, I've found them to be a great source of info on my new found C-1 Carver preamp, and M400 amp. To cut to the chase I'm having trouble with the amp, well more of getting parts, I have 3 shorted output transistors, Motorola C2000, C3000, and C5000 all end in 8113 at the bottow of the first numbers. I'm looking for replaments, recommendations for a good source or there original mororola numbers if these are Carver numbers (they don't cross with NTE and ECG, and the whole internet...via goodle ) . I've got a good handle on the rest of what I've got to do, but those 3 transistors are driving me nuts. Thanks for any help,

-John

Welcome jdcglasnost. Sorry to hear about the amp. Maybe some of the forum members can give you some ideas.

You'll need a TO-3 complimentary pair with at least 150V swing and 12 amps or more sustained current.

A good prospect is the MJ15024/MJ15025 pair

Thanks RichP714, I'll get digging on that. Just to be picky, is there an exact number for this Transistor (such as the motorola number, not carvers). Alright, off to dig the internet for transistors... thanks again.

-John

Thanks RichP714, I'll get digging on that. Just to be picky, is there an exact number for this Transistor (such as the motorola number, not carvers). Alright, off to dig the internet for transistors... thanks again.

-John

That IS the PN, but it's now defunct AFAIK

Sorry just realized my wording, I meant if it was the one that carver had originaly installed (such as if I were to pull one off the shelf at carver, it would really be that transistor), but I just started digging the Motorola sheets on the transistors you pointed out and they seem to be the perfect match. Thank you very much for the information, and can't wait to share the results of repair.

Thanks again,
-John

Good luck, and let us know how it goes

Slight update, ordered all new caps and the new transistors (mouser seemed to be best this time around). Should have pics and testing completed in two weeks. Pics will be coming sometime after.

Man that little M-400 is a bitch to work on.

BillD you got that right: Bitch, or maybe SOB; not sure of the difference.
I acquired one of those M-40s about four years ago, the story being that one channel is "down". At the time I thought that meant one ch had reduced output, but later I remembered that I now live in an age of computer jargon, and he might have meant that one channel was completely out. Anyway, without even trying it I opened it up to look for shorted transistors. Found none, and was going to plug it in for a test, but then realized how miserable it would be to work on further. I ordered a service manual from somewhere and it was such a poor copy that it was over 50% unreadable. Manual and amp sit on my bench pretty much untouched to this day, although lately I have hopes of downloading a readable copy of the circuit and getting back to fix it. Motivation is the problem. I don't have a use for another amp, and I don't hate anybody enough to sell it to them as is. But sometime over the winter when I fell lucky I'll face the music and get back to it.

Robert R

The real problem is that you have to disassemble it almost completely to do anything (all output transistors, etc.) Then, you make a repair and have to reassemble most of it to test it. So, the easiest thing to do is replace everything that might break or be broken all at once.

Yup, I remember that's being the case.

Meanwhile, I looked and found that at the Fest I got a beautiful file copy of the service manual from Tim, and besides being clear and readable, it's VERY thorough, compared to most such productions. The explanations are well detailed. I suppose that was done because the technology was so new to everybody that might work on one.

RobertR

But I don't have the patience of Job anymore!

.....The explanations are well detailed. I suppose that was done because the technology was so new to everybody that might work on one.

RobertR

You'd think so, but the M-500 wasn't too far behind the M-400 and its service manual is simply a schematic. Ad to that it's a completely different way of rail switching and the M-500(t) was a puzzler when it first came out.

That's how I got the job at Carver repair actually; my boss at the time had the job, and brought in an M-500t over christmas break, saying if anyone could fix it he'd give them the repair money. I took him up on it, and soon was doing his M-500t's, M-4.0t's and M-1.5t's.

When he left 6 mos later he gave me the job; that was fun

Post deleted because no longer relevant. I was responding to an earlier post and had missed the one just after it. Sorry about that TFM75.