12 Jan
2020
12 Jan
'20
1:49 p.m.
On 01/12/2020 03:10 PM, Rob Jarratt via cctalk wrote:
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.
The un-connected pin COULD be an electrostatic shield. If
so, it would read like what you get.
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?
Absolutely.
But, are you sure the smell came from the
transformer? Caps are notorious
for being more unreliable.
Can this transformer be replaced (see picture in
blog)? - I suspect not
unless I find a donor PSU.
It is almost certainly a custom unit. It is remotely
possible some similar power supply might use
a close-enough transformer.
Jon