Silverface Champ - Help bringing back to life!

[alberto2000]

I brought out my 1973 SF Champ which I haven't played for two years now, plugged it in, turned it on and there was only a hum and some cracking sounds, no guitar sound - then the tubes got really hot and the 6v6 did even flash sometimes and suddenly I noticed a little smoke and the smell of molten plastic so I quickly turned it off. Two years ago, when I played it last, it was working like a charm.

So I opened it up (have done minimal repairs on my SF Twin Reverb before and got electronics experience) and took a look inside - all looked good there. Then I noticed that the output transformer did leak some red/brownish goo, looks and feels a bit like some kind of wax, and it had dripped down to the speaker cone. So I suspect the smell and smoke was coming from there.

I've attached some images - can anyone here help me? Do I just order a new output transformer? Could it just have broken over 2 years of not being used? Or is it maybe the tubes? Any help is greatly appreciated!

[alberto2000]

UPDATE: ok I swapped both 5Y3GT and 6V6GT (both original I suppose) with some other ones I had lying around (NOS Sylvania and EHX) and now it works beautifully, almost no hum at all, super quiet and good tone as far as I can tell. Must have been the tubes!
Do you still recommend swapping the Transformer? After all it had been smoking and oozing that stuff... and what kind of tubes do you recommend for this amp? I'd like to play it at home in my living room at low volume if possible...

[Snoo]

Looks like you had some sort of short and the transformer overheated. I'm quite surprised it still works.
I'd be tempted to replace the transformer with a Hammond or such to be on the safe side. If you can get hose tubes tested you may find it's not all of them that are dead.
I'd also get the power section recapped. Looks like the can caps I can see have been replaced though so maybe that's been done. I've owned a few of the bigger Silverface amps and always change all the caps straight out as I've seen the mess they make when they go, and are way over life by now.

[Snoo]

Looking again. That's the OP tranny not the mains. DId you have a speaker connected? If not (or you have an issue that end) you will kill the output tranny on a valve amp. Almost looks like that is what happened.

[sookwinder]

the champ and VC do not have self shorting speaker jacks ... they use RCA plugs... so without the speaker connected the OT seas infinite impedance ... very bad for trannies

[alberto2000]

Speakers were connected, it must have been one of the tubes that broke and caused to overheat the tranny... it works fine now but I will likely still replace the tranny with a new one. Any recommendation for where to get one / what exact product to get? I'm in Switzerland, Europe

[ziess]

I can a see the point in picking up a spare, but I would replace the OT unless it's actually failed (ie no sound).

Tommy.

[jdr1014]

I assume Tommy meant "NOT" to replace output transformer unless it actually failed.....and I would agree