Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: rlh5599 on May 10, 2016, 06:58:35 pm
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To all you fine wizards: does anybody rebuild dead power transformers, "reasonably"? I picked up an old webcor push-pull 6V6 amp from a record player, figgerin' I could build a 'Deluxe' style amp out of the chassis, but, alas, the PT seems fubar. SEEMS pretty straightforward, 120v>325-0-325, 3.15-0-3.15, 5v. Ran a 5y3, 2 @ 6v6, 2 @ 12ax7. Just curious I guess.. LMK,
And Thanks!
Ralph
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What exactly seems to be wrong with the PT?
These things are heavy, so unless you are taking it to someplace local shipping will cost you as much as a new one.
Then American labor rates for skilled workers is high, so unless you are rewinding the PT yourself you are probably better off buying a new one. :sad2:
Is the PT shorted, blowing fuses?
Not putting out the expected voltages?
Getting hot and or smoking?
What seems to be the problem? :w2:
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Buy a new one and be done with it. What you're talking about can't in general be done for less than the cost of a new one.
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Thanks guys. I figgered it was more trouble and money than it was worth...
What exactly seems to be wrong with the PT?
These things are heavy, so unless you are taking it to someplace local shipping will cost you as much as a new one.
Then American labor rates for skilled workers is high, so unless you are rewinding the PT yourself you are probably better off buying a new one. :sad2:
Is the PT shorted, blowing fuses?
Not putting out the expected voltages?
Getting hot and or smoking?
What seems to be the problem? :w2:
2 problems: 1: no center tap for the HV out, and 2: it seems the heaters are shorted.
No worries, I'll just buy a new one...
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If it's dead anyway, you might consider opening the transformer up yourself to see if there's anything obvious on the outside of the winding you might correct.
I did this with a transformer in a different category than yours (it had an open high voltage winding). In my case, I was lucky and there was a break in the hair-thin wire just a few turns in from where the thicker lead-out attached. The hardest part was scraping the enamel wire and soldering on the old lead-out. Resulted in a perfect repair.
In my case, I figured I was already destined to buy a new PT, so tearing into the old PT could only have upside. A short may have a good chance of being deep inside the existing coil.
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> hardest part was scraping the enamel wire
A Zippo is the classic "tool".
Old-old "enamel" would come off with strong (kidney-killer) solvent. But newer stuff is tougher, and you may not want to stock 11 different nasty solvents just to find what works on a particular wire.
The very old "enamel" would bubble-off with a soldering iron.