A different Kind of Power Tube Arcing

[Enzo]

Oh, and those new tubes I slapped in there? I don't assume they are good until they prove it to me themselves.

[apehead]

Well, the difference between the principles of a guitar amp, and the transmitters I work on aren't really all that different. Its just that you have to walk inside of the amplifier we use to fix a problem!

As far as the amp goes, I had some 21 year old 6L6GC's laying around that I pulled out of my Peavey Butcher (they are the original stock Phillips). I decided to put them in, due to the fact that, frankly, if they went, I wouldn't care! Played through it for about an hour, no problems yet... but we will see. Thanks for the help, more than likely I'll be back!

[Sweetfinger]

What is a real tech? I've never met one. I wouldn't trust my toaster to most "amp techs" I've run into. I don't see how this is a reflection on my skills as a technician. The amp has a strange problem, I am asking for advice on what could cause those kinds of problems. I attempt to lay out my troubleshooting train of thought as thoroughly as possible, and no one has told me "you are going in the total wrong direction here" yet. In fact I thought the bias circuit was trouble initially (refer to "Four Terminal Pot?"). And it seems after all the tube swapping, we've returned to the bias circuit as the likely culprit for all this mess. So I think it's unfair to just dismiss this problem as over my head, I just don't have much experience with guitar amps. I work on tube LORAN transmitters for a living, so if you have a problem with one of those, let me know.

Two things:
1. No matter how much 'mad' skills you got, sometimes it just takes a second fresh set of eyes to find an elusive bug. In my shop, every once in a while, we'll hit a wall with something, and a lot of times, just handing it off to the other guy will get it fixed.
2. Just because two jobs seem similar, and that your experience should apply, doesn't mean that you will be able to do that job. Example: You custom build formula race cars for a living- have for twenty years- know all about cryogenically treated crankshafts and alloys-n-fuel pumps-n-stuff. Your good friend calls you and told you that his Honda's check engine light just came on. Who's more qualified to look at and probably fix the problem, You with your 20+ years of top level custom building experience, or the kid down at the Honda dealer, who's got 3 years of experience....fixing twelve Hondas a day. You both work on cars for a living.....

...That's not saying you shouldn't wade in to unfamiliar, albeit shallow waters, but sometimes...
http://youtube.com/watch?v=vKagk7L1UkA