Metropoulos Forum

It has been a long time since I have built an amp. I have a completed 50w 1987 project amp that was completed but never tested. It got put in storage and I just got it back (long story). I started to go through the testing steps and I have the 3 preamp tubes in and no power tubes, (SS rectifier). When I test for -DC voltage on pin 5 of the power tube sockets, I get almost -400v DC. The test steps say I should be seeing closer to -50vDC. My bias supply is coming off the standby switch and connects to a 220K resistor. Nothing seems to happen when I rotate the bias pot either. Feels like something is wrong. Is my bias supply wired correctly with this value resistor?

Mike

I suppose I should just delete this post, but maybe it will be helpful for someone as a reminder. My bias network didn't have a ground connection!!! Soldered in a ground wire and now getting ~-50DCV on pin 5. Resuming testing...

Send me some detailed photos so I can help you.
Axeman6@msn.com