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View Full Version : Help (SF) Vibro Champ popping fuses


ibenhad
05-15-2008, 09:12 PM
So here is the deal. Replaced the preamp tubes (7025,ecc83,12ax7a) labeled groove tubes, ElectroHarmonix 6V6 power amp and didn't replace the 5Y3GT Rectifier. The amp was fine and sound great. Today I was messing with some pedals in front , a boss ds1 and a Mosferatu. The amp got a loud hum and popped the fuse. Replaced the fuse and nothing plugged in the amp had a loud hum and popped the fuse within maybe 20-30 seconds...

Looks ok inside nothing seems smoked although I did smell that burned resistor electrical smell. Damn I love this amp it can't be toast. Any suggestions?

RedMan
05-16-2008, 12:48 AM
I would try removing the power tube to see if the fuse still blows.

Blue Strat
05-16-2008, 06:33 AM
What RedMan said. I suspect a shorted power tube.

You should have the amp checked out and the 6V6 cathode resistor replaced with a 1K and cathode capacitor replaced with a 50 Volt cap before slapping in a new 6V6. Otherwise the problem is likely to keep happening.

ibenhad
05-16-2008, 06:45 AM
What RedMan said. I suspect a shorted power tube.

You should have the amp checked out and the 6V6 cathode resistor replaced with a 1K and cathode capacitor replaced with a 50 Volt cap before slapping in a new 6V6. Otherwise the problem is likely to keep happening.

Would the Rat Shack carry those parts?

ibenhad
05-16-2008, 02:11 PM
Here are the Rat Shack parts I think are these correct?

http://www.radioshack.com/product/index.jsp?productId=2062296&cp=2032058.2032230.2032267&pg=2&parentPage=family

http://www.radioshack.com/product/index.jsp?productId=2103625&cp=2032058.2032230.2032267&pg=2&parentPage=family


Thanks for all the help....

Blue Strat
05-16-2008, 02:53 PM
No, you'd want at least a 5 watt resistor and the cap value should be 20 to 25 uf at 50 volts.

ibenhad
05-16-2008, 03:52 PM
Thanks a lot. I am going to stop on my way home. Hope it works. Damn probably shouldn't do anything till I get the 5Y3 rectifier tube.... UGH... That was the only tube that wasn't replaced.

Blue Strat
05-16-2008, 06:24 PM
You still haven't addressed the issue of "having the amp checked out". Many cases like this a "chain reactions", one thing takes out another, and if you merely replace the collateral damage you'll continue going around in circles forever.

Best of luck.

ibenhad
05-27-2008, 07:19 PM
Checked the amp out today and it appears the rectifier tube bit the dust. I haven't done the 6V6 cathode resistor replacement with a 1K and cathode capacitor replacement with a 50 Volt cap before slapping in a new 6V6. I am still going to do them. Just gotta get the 5Y3 tube...