noisy amp B-52

[blink2ce]

Hey all
I am wondering if anyone can solve my problem with my B-52 AT-100 all-tube amp. Whenever I am not playing anything, the amp gives out a lot of noise, especially when my hand is not muting the strings. As I experimented with the problem, I noticed that when I play a note and let it die away, the noise gradually flickers back. Is this because of bad tubes, or something else?
Thanks

[butwhatif]

I just repaired a B52 AT100 amp, and it had a few unusual issues. It had 3 poly coupling caps that had cracked ends, 2 of them were shorted. But the biggest issue was the fact that the circuit board around the pins of V3 had broken down and become partially conductive. This issue made the amp do a lot of frying and crackling sounds. I wound up scraping all the copper cladding and lacquer off the board around pins 2 and 7, and this miraculously cured it.
Also the impedance switch on the back was intermittent, and sometimes made for wierd noises, I hot wired around it and that solved that-

[blink2ce]

hey butwhatif,
shoot that seems difficult. i am new with tube amps, this is actually my first one. That's exactly what i mean, it's a crackling, frying noise. It looks like i will have to take this to the shop. what is "copper cladding" and "lacquer"? and how do you know where the pins are? If you know of a good howto site for this stuff let me know. Because i really don't want to take this to the shop.

[Structo]

hey butwhatif,
shoot that seems difficult. i am new with tube amps, this is actually my first one. That's exactly what i mean, it's a crackling, frying noise. It looks like i will have to take this to the shop. what is "copper cladding" and "lacquer"? and how do you know where the pins are? If you know of a good howto site for this stuff let me know. Because i really don't want to take this to the shop.

Well it is fun to work on this stuff and you can save a lot of money by doing it yourself.

But first the big DISCLAIMER:

There are no user serviceable parts inside this amp!

OK, we got that out of the way. Tube amplifiers have what are called power supply filter capacitors. These are used to filter the voltage so you don't get a lot of humming out of the speakers. Unfortunately, these same caps can store an electrical charge that is sufficient to stop your heart should you touch the wrong thing inside of an amp.
So it isn't really something you should dive into unless you educate yourself or have somebody that can show you the ropes.

The Internet is chock full of valuable information about tube amps so if you are the kind of guy that can take on new knowledge by reading stuff, then you can teach yourself how to work on these beasts. But if you are not and don't feel like you can learn about it, save up and take it to a technician because, no kidding, they can kill you.

Here is a pretty good site. I'll direct you to the part about discharging the filter caps:
http://studentweb.eku.edu/justin_holton/caps.html


http://www.geofex.com/
http://www.freewebs.com/valvewizard/index.html

[butwhatif]

hey butwhatif,
shoot that seems difficult. i am new with tube amps, this is actually my first one. That's exactly what i mean, it's a crackling, frying noise. It looks like i will have to take this to the shop. what is "copper cladding" and "lacquer"? and how do you know where the pins are? If you know of a good howto site for this stuff let me know. Because i really don't want to take this to the shop.

Don't try this at home applies here if you are not familiar with troubleshooting
amps, this was an unusual repair, and your tech should be your guy--