Sansui G-2000 noise from right channel

[Schubert19]

Hello,

I have a Sansui G-2000 receiver. When I turn it on, I can hear a static noise coming from the right channel. The left one seems fine. This noise doesn't change even when I switch the input selector, volume, and balance. Could someone help me? Could it be an issue with the transistors? I have limited knowledge of electronics, but I have already tested and replaced some components of this receiver throughout its lifespan.

The problem:

Regards,
Schubert.

 

[Peter lye]

You might find your answer in below thread

Noisy Small Transistors in G-3000

This is not really a question but more of an informational post. I had an old G-3000 which really got me interested in vintage audio, but the one thing that always annoyed me was that soft hissing noise coming from the speakers, even when there was no source connected. Originally I thought it...

audiokarma.org

Top Ten Worst Transistors - noisy, failure-prone, whatever... and replacements

I've followed AK advice for several vintage solid state receivers now and the difference in sound, from recapping and from replacing "known-to-be-noisy" small signal transistors to be amazing. While following along with others' threads and trying to help out with "consider replacing these...

www.audiokarma.org

I would Check > TR01,02,03,04

 

[Schubert19]

Hello @Peter lye . Thank you for the answer.
I've checked TR01, 02, 03 and 04. They look fine.
I replaced them, just in case. But the problem continue to happen.
Any other idea?

 

[Peter lye]

Hello @Peter lye . Thank you for the answer.
I've checked TR01, 02, 03 and 04. They look fine.
I replaced them, just in case. But the problem continue to happen.
Any other idea?

Get/build yourself a signal tracer.

Post in thread 'Sansui Eight weak right channel' https://audiokarma.org/forums/index...ight-weak-right-channel.1022710/post-16215230

 

[Peter lye]

you still have those notorious noisy transistor in the F-2824 tuner and Pre-Amp circuit board too.



If you have 2sa725/726 and 2sc1312/1313 in you amp, I would replace all !!!

 

[Schubert19]

you still have those notorious noisy transistor in the F-2824 tuner and Pre-Amp circuit board too.

View attachment 2920400

If you have 2sa725/726 and 2sc1312/1313 in you amp, I would replace all !!!

The receiver is working again

The problem continue after replacing all the 2sa726 and 2sc1313. But then I started to analyze the right channel more closely, which was the one with the noise. I noticed that one of the contacts of resistor R69 was loose (the trace on the silicon board had come off, possibly due to oxidation). I replaced that trace with a jumper, and the noise disappeared completely.



Thank you for helping.

Best regards,
Schubert.

 

[Peter lye]

Great work finding the problem yourself.
If you plan to do this kind repair to vintage gear , I suggest you build yourself a signal tracer and a very important tool "Dim Bulb tester"(if you didn't own one) Incandescent light bulb is getting harder to find in the department/hardware store! everyone selling LED bulb now.

 

[Schubert19]

I don't have those tools. In fact, I was reading some publications and trying to understand what a DBT would be, and now it makes total sense. I watched some videos about the Signal Tracer, and I'm going to build one to assist me in troubleshooting.
I'm interested in specializing in this type of repair.