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2283B: Known trouble-some transistors?

tutor_turtle

tutor_turtle

AK Subscriber
Subscriber
I have a Marantz customer I did a complete recap on his 2238B a few years back. The customer was very pleased with the results,
Now a few years have past, he's getting drop-outs on one channel.

I don't have it in the shop yet, I'm having him try out all the switches to eliminate dirty contacts first (and save him a shop charge).

I did not change the speaker protection relay, which I now strongly suspect.

But I do have a question about any known trouble some transistors in the Marantz family?

I have the Sansui/Pioneer list of known bad transistors, the 2238B parts list does not have any of these devices listed.

Any insight is welcome.

Best regards, -Steven M.
 
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There are two 2SC1344 on P200 FM MPX BOARD (Q303, Q304) that are on the DLucy top 10 noisy transistor list, and a 2SC1318 (Q745) on the P700 MAIN AMP. & POWER SUPPLY BOARD which is also on the list. I don't use FM so only replaced Q745 on my 2238B (replaced with KSC2383).
 
Ray66 said:
There are two 2SC1344 on P200 FM MPX BOARD (Q303, Q304) that are on the DLucy top 10 noisy transistor list, and a 2SC1318 (Q745) on the P700 MAIN AMP. & POWER SUPPLY BOARD which is also on the list. I don't use FM so only replaced Q745 on my 2238B (replaced with KSC2383).
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Thank you. I'll change out the amp and power supply devices just on merit.
I do believe this customer (like the vast majority) doesn't listen to FM anymore.
Sadly since Clearwater bought every radio station in the country and turned it into recycled crap, FM radio is no longer worth the bother of repairing or restoring it.
 
Trouble maker transistors don't cause signal to drop out, that's a connection issue; dirty switchs, cruddy relay contacts, cracked solder joints, etc. C1318 isn't a problem child in a Marantz 2238B, only in the power supplies of some Pioneer receivers (and maybe others) where it wasn't de-rated enough.
 
Agreed, haven't received the unit in for evaluation yet, but pretty certain it is the speaker protection relay.
It has had a recent recap, but the relay was not changed out.
 
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