I bought this on Ebay for $5.50 on the off chance that I could fix it.
It was described as having lost picture with a "pop", and with the
observation that a TV repairman said it sounded like it could be a power
supply issue.

I've determined that the sound works OK, as does the tuner and video
signal stage - it outputs the composite video on an AV out socket.

It's clear what produced the "pop" noise.

http://members.optusnet.com.au/sylviae/tv1.jpg

http://members.optusnet.com.au/sylviae/tv2.jpg

Presumably this diode shorted out. It's on a board close the EHT circuitry.

But what are the chances that that's all that's wrong with it? Just
getting the board out to gain access to the underside will be a fairly
major exercise.

Sylvia.