national glenwood model 90

[DrGonz78]

Yeah to be completely honest I am scratching my head too. I still am not satisfied saying the primary is shorted out to the HV secondary. I guess I just want more understanding of what exactly was the problem. Still you tried out that other PT and it worked fine. Strange indeed.

[davohilts]

Yeah to be completely honest I am scratching my head too. I still am not satisfied saying the primary is shorted out to the HV secondary. I guess I just want more understanding of what exactly was the problem. Still you tried out that other PT and it worked fine. Strange indeed.

Yes, and when I checked voltages on the primary with the new transformer they were normal 120-123 VAC, not 324VAC and 444VAC!

I am getting a neon bulb and a 6 volt battery and do some further testing just because I'm curious. When odd stuff like this happens and because I don't have a solid basis in electronics I tend to drift off into the woods looking for anything I can find to solve the problem when if I just completely understood what was happening I would save myself a lot of time and energy.

Dave

[davohilts]

Yes, I tied the test PT to the chassis, fool me once...

[davohilts]

Okay, here's the final update. I received the replacement PT (nice Triad off of ebay) and installed it. Checked the voltages while plugged into my current limiter and things looked much better. Plugged the amp into the wall plug and flipped the switch and the amp came on and didn't blow the fuse. Checked the voltages again and everything was right in the ball park. Reassembled the amp and took it out into the studio and played it for 2 hours during band practice and it sounds great, really nice deep lows and clean highs, just what I'd expect from a properly working Valco.
Again thanks to everyone who patiently helped me through this bit of weird transformer issue, I really appreciate it. My friend will also appreciate it, they haven't picked it up yet so I'll play it a little more. Really nice tremolo and reverb. As a side note, this amp uses a full size reverb tank mounted vertically and the top preamp chassis is notched to accept the reverb tank on one side which is really unusual in my experience.
Dave