Thanks again for this response! Tonight, I disconnected all the output lead wires from the transformer. I put in a fresh fuse and then plugged it in and turned it on. Immediately blew the fuse. So it sure appears it that it's the power xformer. Also, over the past two months of listening to the amp, I was doing 9-10 hour marathon sessions very often. Maybe that is part of the reason the xformer died? Anyways- do you have an idea of a replacement transformer? Looking at the schemtics the A50 comes with, it's not obvious which power transformer I could order to swap out the bad one with. Thanks again for all you do for this hobby - you really are a saint (and talented as well).

Thank you! I will be trying all of this tonight. Once I get past this, I will complete the other two mods. What you are saying makes sense...and it sounds like we should not only do the first MOD and delay on doing MODS #2 and #3....due to the fact there is too much voltage coming thru it.....we should do all of them together once we get all the parts ordered and delivered. I will post an update on this tonight.

Mddawson, I did check the speaker cbles. No shorting. So far, here is everything I have tried. 1. Removed all tubes from the A50. 2. Disconnected speakers. 3. Nothing but power cable connected to the unit and to the wall. 4. Fresh 250v F4A fuse. 5. Turn on. 6. Lights upf or half a second. 7. Goes dim. 8. Checked fuse - blown. I think that elimnates the rectifier tube (or the other A50 tubes) from being part of the issue. I think I will open it it up, grab a volt meter and careful measure from power on/off switch to...where ever. I'm real new to this. Love the amp. Would really like to get it functional. Thanks to everyone's replies so far. One this is, I won't give up!

Thanks for the response! OK - I removed the rectifier tube, then put in a fresh fuse and powered on. Same exact issue resulted. Turns on, lights up for less than 1 second and then goes out. Fuse was definitely blown. The rectifier tube I went with when I did part one of your mods was: SOVTEK 5AR4. All was good for two months straight before this issue. I have not tried to put in the original rectifier tube, since I already did part one of your mod.