Rick (W-A-one-R-K-T) wrote:

I have a line on an old Hammarlund HX-50 transmitter in unknown condition
(been sitting on the shelf for years).

It would be a nice match to my HQ-180A.

General consensus with old radios like that, particularly transmitters, is
that the first thing one should do is replace the old electrolytic and
paper capacitors.

My question is, what's the worst that's likely to happen if one doesn't do
that? Bring it up on a variac, a capacitor blows, makes magic smoke
happen, XYL gets really upset :-), and the fuse blows.

Depends on the radio.

In the case of receivers, interstage coupling caps that are paper can fail
into a short, and take out an IF can. You can't get replacement IF cans
easily these days. So this is a catastrophic failure.

Transmitters are less apt to have delicate things like this to fail, but
they also have less delicate things that are more dramatic when they do
fail.

Some have said you can blow the power transformer but wouldn't the fuse
blow first (unless the power transformer was ready to go anyway)?

Sadly, not. Especially if you run the rig for a long time with the
transformer overheating but the total current below the fuse current.
Remember, the fuse is sized to allow a large starting current in most
cases.

Using an inrush current limiter allows you to use a smaller fuse, which
protects you from such things. I recommend this in newer designs but of
course it's not in place in most boatanchors unless you retrofit it.

Also realize that when can caps fail, the resulting shrapnel can sometimes
damage plenty of other stuff.

General question... which is the best website for information on restoring
old radios? (I know I can google on "restoring old radios" but I'm
looking for opinions on the best from among the few hundred thousand hits
that are likely to come up.)

I don't know.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."