"Jim Land" wrote in message
. 3.44...
Matthew Kirkcaldie wrote in
:

Having found an open primary in the small transformer ....


That's strange. Transformer primaries don't open very often. I would be
inclined to dig deeper to find out why there's an open circuit (internal
fuse open? Bad connection? Melted wire?) and whether there is any fault
downstream of the transformer (shorted component?).

In my professional repair life, I replace trannies in hifi units all the
time, that have primaries that have gone open for no apparent reason. Yes,
sometimes there is a thermal fuse in the primary, and yes, sometimes it's
connected across a couple of external pins so can be temporarily bridged for
test purposes, but I find it rare to then come across a fault downstream,
that has caused a genuine overheat that has led to the failure.

Arfa