Technics SA-300 Problems - Cause or Symptom
Brian Call
New Member
Problem solved! I noticed that the pre drive Q606 C was out of spec, about -0.9V instead of -1.3V. I pulled and tested a couple caps around it, C624 and C632. They looked good so I pulled Q606 and replaced it with another KSC2383. Lo and behold that did the trick! I guess it got damaged when R625 burned. My right channel DC offset is now down to about 3mV. Yay! Thank you for all the help.
For the record, I don't have much experience yet working on these old receivers, but I found the SA-300 very easy to work on. I echo previous comments from others about how easy it is to de-solder, solder. And everything is accessible from the underside. Schematic and circuit board detail are great. Maybe I'll do an SA-500 next which has output transistors instead of STKs. Fun stuff.
For the record, I don't have much experience yet working on these old receivers, but I found the SA-300 very easy to work on. I echo previous comments from others about how easy it is to de-solder, solder. And everything is accessible from the underside. Schematic and circuit board detail are great. Maybe I'll do an SA-500 next which has output transistors instead of STKs. Fun stuff.
Good Morning. I have read your story on the repair of the Technics SA-300 from a couple of years ago. I am faced with the same issues on my SA300. I was just wondering how those STK0039s you purchased from ebay seller ADELEPARTS2010 in China held up? Was thinking of ordering some from this seller. Any help appreciated. Thanks. Steve
Anaxas
Member
The SA-300 has been packed away for a few years, but it was working fine for the year or so I used it as my main system. It was my first repair and I picked up the repair bug (and an oscilloscope ) so now I just listen to what I last worked on. Tempted now to dig it out and give it another listen...