JTM50 Clone Possibly overheating after an hour ?

[jrewing]

Hi Folks,
I am having an issue with a JTM50 clone I built a few months ago. After roughly an hour os so of playing the amp dimed out, it starts cutting off. Not blowing a fuse, just cutting in and out. Is it possibly overheating? The EL34'S really put off a lot of heat. The head cab I have is vented on the back and top. Please let me know what the issue could be.

Thanks,

[neikeel]

So many questions to ask!

Lots, lots more info and pics needed before I am going to play guessing games

[jrewing]

Here is a pic. Let me know what you want a pic of specifically and what questions you have.

Thanks

[YMI5150?]

Are the trannies hot to the touch?

I melted my PT and it was likely due to leakage current from the caps back to the tranny. I'd also check grounds.

[jrewing]

I will surely check those parts. I thought it was a bit weird that I have played the amp for 3-4 hours at a time without having an issue, but it only took an hour to an hour and a half with the amp dimed to for it to start cutting out.
Thanks,
JR

[HTH]

Are the trannies hot to the touch?

I melted my PT and it was likely due to leakage current from the caps back to the tranny. I'd also check grounds.

This would be my first thought too, specifically with the PT.

I'd inject 6.3vac into the heater winding and measure what you get on the primary side (to make sure you're using the correct tap on the primary).