Transformer Fault in a PSU?

[Rob Jarratt]

The PSU in my VAXmate failed recently and I think I have found a problem
with one of the windings on the transformer not ringing when I test it with
a ringing tester. The technical description of the VAXmate says that one
winding is operated in flyback mode and I wonder if that has any bearing on
the ringing test. Also, one of the pins appears not to be connected to
anything else, so possibly a broken (melted?) wire.

 

Can anyone help with the following questions:

 

Does the fact that one winding is operated in flyback mode have any bearing
on the ringing test?

Can a transformer fail with a bad smell with no outward sign of damage?

Can this transformer be replaced (see picture in blog)? - I suspect not
unless I find a donor PSU.

Where should I look for a possible cause of the transformer to fail (if
indeed it has failed?).

 

I have posted more details here:
https://robs-old-computers.com/2020/01/12/possible-cause-of-vaxmate-h7270-ps
u-failure/

 

Thanks

 

Rob