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View Full Version : SAE XXXIB channel troubles, transistor questions


titanstats
05-05-2008, 03:12 PM
Finally got sick of staring at this XXXIB of mine.

Bought it some time ago -- guy said it had a flaky channel. Opened it, recapped it (except for filter caps), replaced a toasted resistor. When I fired it up, the resistor flamed on again, and as I feared, the amp had been more than 'flaky', one channel was cooked. Replacement outputs for this thing are unobtanium from what I can tell -- they are Darlingtons, and SAE proprietary as well.

Only thing I could find was one thread on the restore of one of these. The guy suggested as a first choice 2N6284 NPN 20A 100V 160W , 2N6287 PNP, etc, and as a second choice MJ11015 PNP 30A 120V 200W, MJ11016 NPN, etc. I couldn't find the first choice, so had to go with the second. Does anyone know if these are good choices for this amp, or if there would be other, better choices?

Replaced them today, replaced the toasted resistor again, fired it up and...less than joy. One channel is OK, though the gain is less than what I would have expected from the amp. I'll try it from a pre that I already know tomorrow -- this was just a quick test today. The other channel is there, but distorted -- sounds not so good. Where to go from here? Any suggestions on where to look next? Sounds like this thing is full of hard to find parts, lots of them branded SAE.

I'd like to get this thing up and running -- I know somebody who could use a pretty little amp. :)

phaedrus
05-05-2008, 04:47 PM
One option is to post your query on the Yahoo! SAE_Talk newsgroup. Lots of techs there who have worked with pretty much all the SAE gear. James Bongiorno reads it and posts occasionally, as well. I'm sure they can help you if someone here doesn't come along with an answer.

David

titanstats
05-06-2008, 09:40 PM
Anybody?

Thanks, phaedrus -- I'll check that out. Tired of this sitting around. :)

EchoWars
05-06-2008, 10:53 PM
What are the original output devices?

titanstats
05-06-2008, 11:39 PM
They are Motorola TO3s branded SAE 204 7352 SAE part # 11-0070 and SAE 103 7352 SAE part # 11-0064

Nakdoc
05-07-2008, 08:11 AM
You need to test the driver transistors too. Better yet replace both outputs and drivers. Typically a burned resistor means there are multiple parts that have failed. test all the transistors and diodes if you have the time.