SANSUI G2000 Receiver turns on but with none response

[Schubert19]

Hello,

I've got a Sansui G2000 Receiver from my father in law last week . When I turned on only the panel lights work, all other buttons give me no responses. I've already tried to use FM, AM, Aux, Phono, but nothing happens. I plugged a speaker in output and get only noise (this don't change if I change the volume). I measured the output voltage on the speakers output and got 25V. I know It's hard to analyse the possible problem with only these information, but I live in a small city in Brazil, so find a technician to help me is not an easy task. I'm sending some pictures of the electronics. Any advise will help a lot!



Thank you!

 

[Hyperion]

It looks very clean but unfortunately it seems from your description of the fault that you have blown output transistors - as indicated by a reading of 25V on the speaker terminals. This is not an easy fault for an electronics novice to put right, so in my opinion this needs to go to a tech to put right. The output transistors are unlikely to be the only components damaged, and the unit could really do with being reconditioned as it will be very tired by now.

I hope you can find a local technician.

The service manual is available here https://www.hifiengine.com/

Good luck with it.

 

[Schubert19]

Hello Hyperion,

First, thank you for your answer. I was thinking about testing the capacitors to see if they are dead, if yes replace and retest the receiver. What do you think?

 

[Hyperion]

Well you could, and the capacitors may well need to be replaced eventually. But it is always recommended to only change components to cure the fault and nothing else, to begin with. Then afterwards, when the original fault is resolved, only then think about replacing tired but working components.

 

[Tom B]

I agree with John,
Always fix the problem at hand before changing anything else, to prevent compounding the problem with another problem.

 

[Schubert19]

Hello guys,

Just to update you. I got the service manual, a multimeter, and some videos on Youtube (how to test electronics components) and now I have my receiver working!

Have a look:

There were around 10 resistors that should have tens of ohms giving megaohms to the circuit (they looked fine from outside, but were burned inside). Capacitors, transformer, transistor look fine. I just replaced the resistors and the sound, signal and tunning come back to life.

I'm having problem to keep the FM radios with clear sound (auxiliar input sounds really).

Next steps: Buy a FM radio antenna to check if it is low signal problem, and restore my Sansui P-D20 turntable (as now I have a receiver).

Thank you guys.

 

[Hyperion]

Wow - that is an excellent effort!

Well Done!

 

[Schubert19]

Hello guys,

After more than one year working my receiver starts to show another problem. Now one of the channels (the right one) after a couple of minutes turned on starts to make a loud noise (like when you have some faulty contact on the speaker). It keeps the same even if I change the volume, balance, input selection... It only stops (of course) when I turn off the receiver or unplug the speaker. I have already changed the speaker, cables, and the problem continue. Do you have any idea what can be the source of this issue?

Best regards!