Need Help: polytone amp went silent!!

[KCKC]

Hope you folks can help.

I have a polytone minibrute iv. Approximately 16yrs old. Never had a problem til now.

It has two unlabled jacks in the back: one for headphones, one for extension cab.

I plugged a 1/4" to rca female adapter in the back so I could go direct into a behringer UCA-202 unit (this unit allows me to connect to my USB and record direct to PC). Well I plugged in the jack to the back of the amp and heard the sound go off, so I figured I was in the headphone jack. However I didn't proceed to record at that point.

I go back a few days later and fire up my amp and nothing. No sound. Power light is on, but no sound. There are no plugs in the headphone jack. I don't even get any electrical pops when unplugging guitar cord.

Is it possible if a 1/4" plug that is
NOT attached to an extension cab
BUT is plugged into the extension cab jack short something inside the amp to create my silent amp.

All input's appreciated!

thanks,
kc

[voodoostation]

Another poster had a similar issue a week or two ago, garytelecaster, I think. I'd be inclined to believe the jack you plugged into is dirty, one of the contacts has stuck, not allowing the signal to be sent to the speaker. Try some contact cleaner and inserting and removing the plug from the jack you were using. I'll keep my fingers crossed fer ya!

[iim7v7im7]

Most Polytone's are fused, did you check to see if its blown?

[KCKC]

Yep, checked the fuse. It's good.

I was thinking the same thing voodoo. I've never used the headphone jack and it might be stuck "on" even though there's no plug in there?

I will try the contact cleaner.

thanks guys,

kc

[Mutato]

I own a 70's era (Velvet Beauty) Minibrute.

Mine has a lot of corrosion on the bottom back 1/4" jacks. I think the proximity to it being near the basement floor most of it's life. Also in my case, possibly a salt water flood at a New Bedford practice space! This has really has left them working, but in bad shape.

So you can see that it's most likely a bad connection inside that could be fixed by cleaning. They really pack the guts in tightly in them. I've opened mine a few times, but never serviced it. I did have it repaired after it died (during the flood!).

[KCKC]

Originally Posted by iim7v7im7

Most Polytone's are fused, did you check to see if its blown?

iim7v7im7, I had checked the fuse on the back. That was fine. You were probably referring to a fuse on the "inside" and I didn't pickup on it. The other day an electrician friend of mine said "Take another look inside. There might be another fused tuck away in there."

Removed the back again and sure enough, there it was! had to move some insulation but tucked down at the bottom was another fuse in all its blown glory!

69 cent fix!

[Big John]

OK, but what caused it to blow ?, maybe the tech should give it the 'once over' for safety.