Scored an Akai 635D

[jan_stevns]

.....Any ideas why the transistors in these units seem to be failing so much?

Most of them seem to have corrosion on the leads, apparently this corrosion don't stop at the plastic housing - it seems to continue into the chip.

Typical symptoms are lack of amplification ( low Hfe ) - and/or noise

2SC2310 seems to run absolutely fine as a replacement - sofar i haven't seen any problems using those instead.

Again - there isn't much issue in it - if you have an Akai suffering audio-problems, there is 99% chanche it is a transistor problem. every tech working with Akai's are aware of it.

(some Sansui receivers/amps has the same problems with those transistors)

 

[Chappy]

Most of them seem to have corrosion on the leads, apparently this corrosion don't stop at the plastic housing - it seems to continue into the chip.

Typical symptoms are lack of amplification ( low Hfe ) - and/or noise

2SC2310 seems to run absolutely fine as a replacement - sofar i haven't seen any problems using those instead.

Again - there isn't much issue in it - if you have an Akai suffering audio-problems, there is 99% chanche it is a transistor problem. every tech working with Akai's are aware of it.

(some Sansui receivers/amps has the same problems with those transistors)

Thanks for the info. Perhaps the corrosion has something to do with acid in the solder flux? I found similar issues with old tube organs. When I de-soldered the capacitors that I was after I found that the leads were brittle. They broke as soon as I tried to bend them.

The Akai deck just got packed by the movers. Hopefully within a few months after settling in to my new house I'll have a chance to start repairing it.

Steve