50's Rickenbacker M8 amp died today. Help!

[twiggybush]

On a whim today I opened my amp and put a power cap in parralel to the existing to see if the amp would clean up. I put that cap in backwards. Now the amp is dead. Filaments light up, tranny overheats and smokes. I have no substitute tubes on hand. The overheat was mild so I'm hoping the tranny is ok. Since I know the cause, I was hoping someone might hazard a guess as to what went wrong. Also wondered why 1 power cap is axial and the other is can mounted? Twas the axial I messed with. I'm unemployed and have a voltmeter. If I had a job I would'nt have this problem. Kman

[oc disorder]

Hi Kman and welcome to the forum.

Well I guess if its this one http://www.rickenbacker.com/pdfs/m8.pdf
try unplugging the 5Y3 and hopefully everything should still light up but
the transformer shouldn't be getting hot.
If thats the case it's time for a new 5Y3.
Iv'e heard they prefer a low capacitance value filter 30 to 50uF but I havn't checked that out.

[twiggybush]

So far so good,

Thanks OC, Yes that's the schematic. I pulled the 5Y3 and the tranny was cool. With the tube removed I checked the resistance across the supply and it read zero??? If my tranny is still good, would I not read some resistance? I could take a reading on the 2 red wires from the tranny supplying the 5Y3 but I'm clueless as to what voltage I'd be looking for. Being center tapped would'nt I have to take the readings between ground and each wire seperately?

[oc disorder]

Yes you should get readings between pins 2 & 8 and 4 & 6 of the socket
see attached diagram.
You should also get a reading to ground from pin 4 and pin 6.
Both these should add up to the reading between 4 & 6 give or take...
May need a higher setting on the meter?.... check the mains in (unplugged of course) across the plug pins with the switch on.
That will give you the resistance of the primary (Just to check the meter - no other value ! )
Well you could measure the voltage but risky from a safety point of view.
Obviously 2 and 8 will give approx 5v (higher as tube unplugged) and 4 & 6
will be 2 or 3 hundred volts !
Voltage between 4 and ground and 6 and ground should be half of voltage between 4 and 6.
But the resistance reading should tell you if you have to buy a new transformer as well as a 5Y3.
Regarding the capacitor types probably ease of manufacture or what was on special at the time.

[twiggybush]

Looking good,

All three windings showed they were working. 350V,5V,6.5V. So I'm confident enough to order the 5Y3 and the capacitors it needs. Thanks for the rectifier tip, your checks in the mail (: I'm wondering why one 40/450 cap is axial and the other is in a can soldered to the chassy. Would that be difficult to extract? The 25/25 shows leakage and an .01/600 tied to the preamp looks overheated. This amp is a virgin part wise. The resistors all look like hell but the amp works fine so I'm wondering how ambitious an overhaul I might want to get into. Thoughts appreciated???