Another vertical output transformer????

[Giulio Maiocco]

Hello, my 2 eurocents worth about vertical output transformers, if I can...

I have no experience with color TVs, but I have a 1954 27" TV that burned it's vertical output transformer more than once. When I unwound all the primary winding (in reality, it's an autotransformer coupling a 6SN7 tube to the yoke), composed of 6000 turns of 0,10mm enamelled wire, I found many spots of verdigris on the interlayer paper, not on the copper wire, and some arcing that burned the winding open. So, last time it happened, I replaced the paper insulation with mylar tape, the Yellow tape used in SMPS power supplies. This tape is quite thin, 0,05mm, but it should offer more dielectric strenght (it should withstand about 1Kv between layers no problem) and it's not water-absorbent, unlike paper. Ok, it does not look anything like the original paper insulation, but until now, it works like a champ.


Cheers

Giulio