Sansui R-5 Static LC

[electrotek]

Hi everyone! Recently picked up an R-5 and noticed static (buzz) in left channel only. Happens from power up and doesn't seem to go away. Tried a few tests - same result:

- Speakers only (A+B)
- Headphones only
- Different inputs or no input
- Different power socket (direct into wall)

I don't have the possibility to swap channels to test that. Treble accentuates it and it's not linear... e.g. it's less pronounced on volume 5 than volume 4.

Any thoughts as to cause or steps to diagnose? Service manual here: https://www.hifiengine.com/manual_library/sansui/r-5.shtml

If I need to replace parts, open to improvements. Thanks in advance.

 

[LBPete]

Is it "static" or a buzz? Static is random, a buzz is usually repeats at a given frequency, typically 60hz. Do you hear it from the speakers or is it coming from inside the case?

- Pete

 

[electrotek]

Is it "static" or a buzz? Static is random, a buzz is usually repeats at a given frequency, typically 60hz. Do you hear it from the speakers or is it coming from inside the case?

- Pete

Hi Pete, thanks for responding. Definitely not random and sounds highish in pitch, so buzz sounds right. Heard through speakers and/or headphones (tried all combinations).

Just tried putting my ear to the top of the case and I do hear a humm, on the left if looking at the front. Different noise/pitch to the output (transformer humm?).

 

[LBPete]

If it's coming from the speakers it will take some work and an oscilloscope to find. You basically have to isolate it to a particular board and go from there. Sorry, no easy fix for this one. You can hit the boards with freeze spray and you might get lucky.

- Pete

 

[electrotek]

Thanks Pete, will consider the freeze spray, re-soldering, and I guess focusing on (pre- and) left channel circuitry first.

 

[sesana]

Hi everyone! Recently picked up an R-5 and noticed static (buzz) in left channel only. Happens from power up and doesn't seem to go away. Tried a few tests - same result:

- Speakers only (A+B)
- Headphones only
- Different inputs or no input
- Different power socket (direct into wall)

I don't have the possibility to swap channels to test that. Treble accentuates it and it's not linear... e.g. it's less pronounced on volume 5 than volume 4.

Any thoughts as to cause or steps to diagnose? Service manual here: https://www.hifiengine.com/manual_library/sansui/r-5.shtml

If I need to replace parts, open to improvements. Thanks in advance.

Sorry to ask 8 years later, but by any chance do you figured the problem and still remember it?
I have the same model and I hear the same noise, but from both channels. It goes up with volume and is also related to the treble knob setting.
It's sound is overall very good, despite this, but I'm guessing it is a bad sign of it's aging.
I would apreciate any tips on what I could do to improve its sound and prevent further damage - besides recapping it, which I should probably do, since it has more than 40 years by now.