Another vertical output transformer????

[Electronic M]

ESR is a poor safety test for original capacitors in a tube set because it does not check for leakage at full working voltage. To properly confirm the safety of those caps you need a Heathkit C-3 or one of the other eye type capacitor checkers of the time period.

I recently unwound the primary of a late 60's Zenith vert. Xfomer out of a monochrome set, and was surprised by the lousy (thinner than paper and brittle like onion skin) insulation between layers of the primary, and more surprised that they used the exact same crap between the primary (connected to B+) and the secondary (connected to ground)....I'll give you one guess what the failure mode was...

[Kevin Kuehn]

Agree that testing equivalent series resistance(ESR) has no relevance to high voltage leakage(insulation break down).

[miniman82]

Originally Posted by Electronic M

...was surprised by the lousy (thinner than paper and brittle like onion skin) insulation between layers of the primary, and more surprised that they used the exact same crap between the primary (connected to B+) and the secondary (connected to ground)....I'll give you one guess what the failure mode was...

You should see the vertical dynamic convergence x-former out of a CT-100, thousands of volts on those it's no wonder they all fail eventually. Jeff the gentleman I bought my set from had a whole series of pictures burned onto CD-ROM of him taking the thing apart, and one where it clearly arced through from primary to secondary. I really should upload them.