GavinI ) writes:
Yukio YANO Wrote:
GavinI wrote:-

-
Check for a blown INTERNAL fuse in the Transformer housing !

Yukio YANO


Thanks for the suggestion Yukio.

If there is a fuse it's hidden well inside the transformer
unfortunately.


I don't think you are looking for an actual fuse. It would be a piece
of wire (or the whole primary winding) that has such high relative resistance
that if too much current is drawn, the winding opens. This is the same
principle as an actual standalone fuse, in that inside their casing
there is a small bit of wire that will open up if too much current is
put through it. But the transformers are designed so they'll open up
if too much current is drawn.

The result is not a "blown fuse" but an open winding, which is what
happened to you.

Of course, that leaves open the question of why the transformer opened,
so before replacing it, you'd want to be making sure nothing on
the secondary has gone bad to draw too much current.

As for voltages, you can at least get an idea by looking at the
electrolytic capacitor(s) in the power supply. The secondary will
go through some rectifier, likely a bridge but maybe some other
configuration, and then to some filter capacitors. Those (and they
are relatively big) will have a voltage rating marked on them, and
that rating will be higher than the transformer output voltage. How
much higher is why it only provides an idea.

Michael