Hey folks, I was recently jamming through my 5F2A. I noticed that when cranked up to 10, (ya that happens a lot) I was loosing some volume. I pulled the upper rear panel off and laid the amp speaker down on the floor and watched the tubes while I hit the front end hard with my ES-335. Lights out now, in the dark, I could see the 6V6 put out a little white glow when played a hard E, then fade dark again as the note faded off. Hmm.. Fireworks in tubes. I estimated I had a bad 6V6. I swapped it out and saw this happening again with another new tube. I shut things down for further inspection. My 5F2A was a very early amp build for me. Pretty green. I noticed that the 6V6 cathode cap and resistor were touching. I pulled them both and put in new. Just in case. I cleaned up some other lead dress and a few ugly solder joints. Turned the amp on. No sound. A slight buzzing from the speaker that's it. Weird. I pulled out my DMM and measured all resistor values. I checked every single connection against my Weber layout sheet. I triple checked it all again. All good. No ground problems. All seems well. I hooked up my DMM , when I turn the amp on I watch my B+ climb to 500V DC or so, then there's a slight pop in the speaker and down she goes to about 350 and stays there. Again I re-inspected everything, all connections look good. Swap in a different 6V6 again. Same thing. Swap in a different NOS 5Y3. Same results. Folks I think I may have a failed output transformer. The B+ goes to the primary side. Seems that it builds up, then a slight pop and B+ drops. The buzzing in the speaker I am hearing is the short in the OT maybe? I'm thinking so. I am not sure how to test an OT, however maybe I should swap a new one in. See what happens? I have not had this happen before, but can a failing 6V6, take out a OT? Or can a failing OT show fireworks in the power tube as I saw? Thoughts?