Hallicrafters T-54 HV transformer

[dtvmcdonald]

Originally Posted by dtvmcdonald

Not all Hallicrafters T54s have HV problems. Mine, using the transformer it came with,
works just fine, for well over an hour. I've never tried it longer. The transformer
did not work when I got it, but that was just a bad solder job attaching one of the thin
wires to its terminal. I had no problem finding a replacement, I forget where ... they are not unobtainium.

I cooled it better by raising the lid over the HV enclosure 1/2 inch on standoffs.

I have two of these, one to be donated to the ETF. This spring both worked fine for over an hour.
measurd to have very little sag.. Yesterday both drooped to 2.5 kV in about 15 minutes.

Today I am running one with the HV rectifier unplugged. After an
hour it has begun to slowly recover. (The AC measured on a scope.)
I do have a NIB one .. but not two. If its humidity it should eventually
recover.

What to do?

Edit: after another hour its back up from 50% normal to 80%. Note: That's still no rectifier.

2nd Edit: after another 30 minutes it was up to where it was at turnon. I reinstalled the rectifier
and the voltage went UP ... as expected since it was not resonating properly with no rectifier.
After yet another hour the DC voltage was 5 kV.

Tomorrow will tell more.

3rd update: the next day (the 4th) the set turned on and worked fine, never having drooped in HV in 45 minutes.

I think these sets merely need to be used regularly.

[kvflyer]

Originally Posted by dtvmcdonald

I have ...


I think these sets merely need to be used regularly.

Can't disagree with that...

[dtvmcdonald]

I tried my 2nd T54 chassis. It was not as bad a dip, but took like three hours to recover.