"duke" wrote in message
oups.com...
I was just made the recipient of a B600, with the 6A41 chassis. It's
in great shape, and as it was a gift from dear friends, you can imagine
my joy. I want to fire it up, but I don't want to burn out anything.
Any tips for first juice? I don't have any special equipment beyond a
multimeter.

Check out:

http://antiqueradio.org/dimbulb.htm

I'd eventually replace any paper capacitors in the radio. The paper
deterioriates with time, and those caps won't be in much better shape than a
1950s era newspaper. I'd also test the resistors with an ohmmeter. Most of
the resistors are probably still in spec, and a few will be close enough,
but there are likely to some which have at least doubled their resistance.
I'd also test the electrolytics and replace those which have high Equivalent
Series Resistance or more than a normal amount of leakage at their rated
voltage. Few old electrolytics pass both tests, and it's best to replace
the electrolytics you can't test. Use decent replacement electrolytics,
too. It's my opinion that alot of the inexpensive electrolytics are
designed for today's disposable electronics. I also like to install fuses.
A zener diode across the filament string will protect the battery tubes from
overvoltages.

I know this all sounds like a major pain in the ass, but it's really no so
bad. A properly repaired vacuum tube radio is both quite safe and reliable.
But I'd never trust one with crummy old paper caps, leaky electrolytics,
etc.

By the way, electrolytics usually fail by either drying up and developing a
high ESR or simply opening up. Either way, they take themselves out of the
circuit. This will result in a big hum in most radios, but it might simply
silence these radios. Without the first electrolytic charging to near the
peak of the AC waveform, both the B+ and the filament voltage go way below
spec. Battery tubes don't work well with insufficent voltages.


Also, it appears that either there is some odd factory
option (I doubt) or a mod made to add an additional speaker. Has a
jack that is mounted to the side and a pot inside the box. It was
nicely done if aftermarket, but does anyone know if this could be an
original option? Thanks for the help.
duke