Sansui 210: A channel dead and humming

[davstev]

Hi folks, I have acquired a nice Sansui 210 that has one channel with a consistent humm but with no actual signal. Hum is unaffected by volume. Other channel working fine, no hum.

Any suggestions as to where to begin? Previous owner said there was an audible pop of some kind leading to its malfunction.

Checked the fuses, they all test ok. I also pulled the three biggest caps on the power supply board and tested them and they're ok. Close inspection and nothing looks burnt, leaky or blown up.

Thanks for any leads. Considering a full recap if it comes to that. I have the schematic.

David

 

[milo63]

If it's just one channel it's probably on the amp board, not the power supply.
Download the service manual and start checking voltages on the amp board, maybe pull the output transistors and test them.
If you want to play with it build a dim bulb tester to keep the magic smoke inside.

 

[davstev]

Thanks so much, a good start.