DEAD SUT's

[Shian7]

Originally Posted by bob orbell

Hi Shian & Dik, the problem that I have found is the secondary winding is soldered, what seams to be at a centre tap, and it corrodes at this joint, I have put back into servis 11 to date, with 1 f##k up, to undertake a fix, you first need to remove the cap which is soldered, then using a heat gun, melt the wax inside and remove the transformer, now here's the delicate bit, follow the red and black wire to there temination and very gently cut the white tape inbetween the two cables to reveal the two ends that are soldered together, you now should now have the problem, clean and resolder and cheak for about 680 ohms, push the tape back and reasemble. oh and a good pair of eye's is mandatory. Good luck. BOB

Hi Bob,

Thanks for the info, I think I'll have a go at it. It's already busted, so what have I got to lose!

Cheers,
Mike.

[Gerry B]

Hi all
Mine was (is) cylindrical too.

cheers
Gerry

[bob orbell]

Originally Posted by John Caswell

Hi all,
I would be very interested to know which transformers these are.
The cylindrical ones or the cubical ones?

John

John, the one's that I have fixed have been from WAD & WD, all are in a cylindrical case and all transformers are EI, this includes 1-10 & 1-20, it may be that the manufacture has used acid flux because there is a lot of green corotion I have never seen any other's. BOB

[bob orbell]

Hi Mike, yes have a go your mother did as long as you are very carefull you should do it, like you say you have nothing to loose. BOB

[John Caswell]

Bob wrote
"it may be that the manufacture has used acid flux"
Not necessarily, we used to have quite a problem in the 50/60/70s with what was called "green spot" disease which affected primarily IF transformers and also RF coils wound with fine and/or "Litz" wire and often this was nowhere near the soldered joints. So I am not sure about the cause of this at present, but it was definitely due to atmospheric corrosion as it was worse in the tropics.

John

[bob orbell]

You could well be correct with the damp John, or it could be contamination from someone's fingers at the assembly stage, all the one's I have fixed, the break is in the same place, some with more corrosion than others, and it was/is a joint, the same thing happens with old magneto coils on the very fine secondry. BOB

[Shian7]

Hey, it worked... thanks Bob!

[bob orbell]

Well done that man.