[V8] Old music or good music...
Mike Arman
Armanmik at earthlink.net
Tue Apr 10 11:29:27 PDT 2012
For any of us who happen to have older tube-type electronic equipment stashed away and plan to use
it again "someday" or sell it - do NOT "plug it in to see if it works" because it won't!
The electrolytic capacitors (the big, aluminum cylinders) in the power supply will have dried out by
now, and the results could be quite spectacular - for a few moments, anyway.
Open the covers (top and bottom) and inspect FIRST. Look for whitish "glop" oozing out of the bottom
of the power supply electrolytic capacitors - if you see any, that cap is bad. Check them for bulges
as well - a bulged capacitor is trash. Look at the silver, reflective spot on the inside of each
vacuum tube. That's the "getter" and it "gets" stray air molecules to keep the correct level of
vacuum in the vacuum tube. If the getter is white instead of silver and reflective, the tube is bad.
Use some contact cleaner on all the switches and controls. After 30 or 40 years, these things get
quite oxidized and nasty. Dirty controls make for noise in the speakers, and if they are bad enough,
can block the signal entirely. Work each control a minimum of 20 or 30 times, spritzing a little
contact cleaner into the control from time to time. (Radio Shack sells it.)
Connect a pair of speakers and some audio input source, some of these things don't like to run open
circuit.
NOW you're ready to put the power to it BUT: The key here is to use a Variac (adjustable line
transformer), set on the lowest setting, and SLOWLY, over a day or so, gradually raise the voltage
to full line voltage. This gives the capacitors a chance to re-form (if they are going to), and when
you're all done, you will still have something to sell or enjoy.
I have a fair sized stack of Dynaco equipment waiting for "someday", and probably 600 classical LPs,
some of which are brand new and still in the cellophane wrapper - came from an estate, the guy was
the culture critic for a major newspaper "up nawth" and the record companies sent him dozens of
brand new LPs, most of which never even got opened.
Best Regards,
Mike Arman
90 V8Q, gas tank full of glop
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