Did my amp really fix itself?

[bobshbob1]

I went to play my Peavey Butcher tonight, let it warm up, flipped the standby switch, and as it came on there was a scratching noise for a few seconds, then it played normally for a few more seconds, then it shut off, as in the green standby light went out, not the red power light. I turned it off and unplugged it, figuring a fuse had blown. There was a slight burning smell when I was opening it up, but all the fuses checked out okay.

There is, however, a burnt-out area between two of the traces on the preamp board. I scraped away the burnt stuff, I'm not measuring any continuity between the traces at all, and they seem pretty much intact. I have a feeling it may have been a stinkbug getting burned crawling inside the amp (my house is infested with these things; there were two more crawling around inside the chassis when I took it apart). One trace is for the filaments and the other is at B+ sooooo I figured a bug could've gotten zapped pretty good.

Nothing else looked amiss inside the amp, so I tried firing it up again. Now it is playing completely normally, at least at low-ish volume; it's too late to really crank it up. So, am I good to go? Or are there other precautions I should be taking? This amp is built like a freaking tank, but I just figured it's probably better to ask those that would know.


One more thing I noticed: the filter caps on this amp drain on their own pretty quickly. I went to discharge them when I was looking inside the chassis, and they were only holding about 10 V. My other amp will hold 400 volts for days, though. Why would the Butcher discharge so quickly? And if it's possible to automatically discharge the caps, why aren't more amps designed like that?

[Raybob]

I...There is, however, a burnt-out area between two of the traces on the preamp board. I scraped away the burnt stuff, I'm not measuring any continuity between the traces at all, and they seem pretty much intact. I have a feeling it may have been a stinkbug getting burned crawling inside the amp ... Now it is playing completely normally, at least at low-ish volume; it's too late to really crank it up. So, am I good to go? ..

Sounds like you fixed the 'bug' with the amp but I would put silicone in every corner of that chassis and fill any holes in chassis that are just open holes, if you want that repair to last in a bug infested place.

[olddawg]

Sounds like you fixed the 'bug' with the amp but I would put silicone in every corner of that chassis and fill any holes in chassis that are just open holes, if you want that repair to last in a bug infested place.

An old blues buddy of mine said he used to put old tuna cans with an inch of oil in then and set every leg of his bed in one to keep the roaches from crawling on him at night. Maybe it would work for stink bugs.

[guitarmike2107]

sounds like you need to phone rentokill..

Did it stink inside your amp, I can't imagine one of those bugs getting zapped and not putting out a terrible stink.

[jmaf]

You could give the amp a thorough review, checking caps and resistors, checking electrolytics for obvious bumps and the such. Other than that, your amp may have de-bugged itself indeed....

[defaced]

One more thing I noticed: the filter caps on this amp drain on their own pretty quickly. I went to discharge them when I was looking inside the chassis, and they were only holding about 10 V. My other amp will hold 400 volts for days, though. Why would the Butcher discharge so quickly? And if it's possible to automatically discharge the caps, why aren't more amps designed like that?

I've got 5 bucks on balancing resistors across the filter caps in the power supply. Probably two 220k resistors for each stack of capacitors (assuming it has series caps at each filter node). You can add these resistor(s) to your other amp with no consequence to it's performance.

[Jazz P Bass]

[QUOTE=bobshbob1;212221
I have a feeling it may have been a stinkbug getting burned crawling inside the amp (my house is infested with these things; [/QUOTE]

I was resoldering a Hartke HA3500 with my "magnifier helmet" on.
Out comes a stink bug from the heatsink tunnel.
Right in my field of vision.
You can guess what my reaction was.

[52 Bill]

I remember the first time I ran across something like this. It was one of those Peavey Classic amps with the solid state preamp and tube output stage. There were the remains of a two inch long roach that cooked itself crossing the small pc board that the 6L6 sockets were mounted to. Blew the fuse and carbonized the board. I couldn't figure out how it got in there. Maybe they're more flexible than they look.

[bobshbob1]

Well, all the caps look good, and I did indeed see the 220k balancing resistors, so maybe I'll add this to my other amp; it is a nice thing to have. I can only assume the bug must have gotten in through one of the jacks. Crazy...Maybe I can find some way to bug-proof this amp, I dunno about anyone else from the mid-atlantic area, but my whole neighborhood is crawling with stinkbugs...