"Scott Dorsey" wrote in message
...
Paul P REMOVE paul @ REMOVE ppinyot . REMOVEcom wrote:


I'd be curious how the original one failed, though.

Mechanical failure.

It looks good but does not conduct. It threw me for a while before I
actually tested it instead of looking at it.

One of the first things they taught me in tech school in the 70's. Ohm
out
the lamps and fuses.

I know this sounds weird... but try applying 16V to the thing with a bench
supply and see what happens.

I have seen some lamps that seem to be an open until power is applied
and then they become normal. I don't know what causes it, it's as
if a layer of corrosion built up on a contact somewhere.

Odds are it really IS bad, but five minutes will make sure.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

These are ballasts that help to limit the current on the input transformer
winding, or blow if too much. The FT-757 uses a grain-of-wheat bulb tacked
onto the board. It is probably not critical, but it should be noted that
smaller lamps may coat the envelope if they blow hard, leaving them
conductive. Can be a problem with fuses too.