Transcendent Sound GG help

[nelsondog]

Hi there, I just got a used preamp and it's making a loud, low level hum and one side won't play music. Any ideas what I should look for in order to fix it?
I have replaced the coupling caps with 1uf Russian pio.
Thanks for looking!

 

[merlin2069er]

I'd start backwards and make sure your outputs are isolated from the case, and they're properly grounded.

Then I'd check the output voltages out of your power supply. Make sure that's working.

 

[merlin2069er]

It's good to have a schematic in front of you while troubleshooting...

Check the output voltages from the power supply +200 / -200.

 

[nelsondog]

Thanks Merlin! I'll have a look...
Also looks like some poor soldering at the diodes. Do I need to heat sink before reparing?