View Full Version : Put power tubes in the wrong way!!!Help!
EETStudent
12-30-2007, 08:23 AM
I was looking at a set a power tubes in an old Pro Reverb, and i didnt realize but the center piece had broke off in the socket. well i put the tube back in and is not aligned correctly. I quickly corrected it, and although the tube still glows it doesnt appear to function. The amp is a million times quieter.
The resistors across it are still fine. What do I do?????
Start looking for missing voltages. Pull the tubes and measure at the sockets. Got B+ at pins 3 AND 4? Got bias voltage at pin 5? pins 8 all grounded?
And make sure you have the speaker plugged into the correct jack. Use the main speaker jack, NOT the extension or auxilliary speaker jack.
EETStudent
12-31-2007, 07:59 AM
Enzo, thanks a lot man. However, after about an hour of letting things sit and putting in some new tubes, the thing worked fine again! Dont understand it, but gotta say I am relieved. That bit of info and troubleshooting tips you gave me are very much appreciated. Learning new things is exciting.
There seems to be a bunch of colleges in COlumbia, where do you go? I suspect they don't teach tube circuitry there.
EETStudent
01-02-2008, 07:18 AM
I go to Midlands Technical College. First year electronics major, and I dont believe they are teaching tube circuitry there unfortunately. Heck, the only other college that I know teaches electronics would be U of South Carolina. What other colleges do you know that teach this sort of thing? To be honest, Ive had a few doubts as to the direction of my studies. Have been told a few times to keep tube amp work as a side hobby, but thats not what i want in the least.
I won't tell you to find something else, but like an athlete planning on joining the pros, it is wise to have a backup plan at least. Of all the folks out there who work with tubes, inlcuding the folks here, SOME have a nice living from it, but most do not. You can get a job in a music store fixing stuff, but then you are working in a music store fixing stuff. Of all the engineers working at all the guitar amp factories, only a small portion work in the tubes. I own this repair business here, and believe me, I don't buy steak at the grocery very often.
Look at the help wanted ads in your area. How often do you see electronics tech openings? Now how many of those might possibly involve tubes? Not many. More openings in communications, internet and computer systems, industrial controls, etc.
Very few places will teach tubes in a general electronics curriculum because ther is darn little call for it.
All that said, I think tubes are very intuitive and can only enhance your understanding of electronics. Just don't bet the farm on them.
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