26 Nov
2002
26 Nov
'02
5:47 a.m.
I'd check the diodes for shorts too. What might work here is a variac
with a 100W lightbulb in series. Ease up on the voltage, and the
lightbulb will limit the current to a safe value and give you a visual
warning.
If all else fails, you might have a heater-cathode short across one of
the tubes putting a load on the B+. They loved to have all sorts of
positive and negative voltages to make those tubes work as DC amps.
A book here would be invaluable, and some serious head-scratching time.
Gary Hildebrand
St. Joseph, MO
John Allain wrote:
Hi,
I happened upon one of these beauts through one of those
'oh, you collect old computers, come back next week and
I'll have something' type deals. This is a Tektronix 310A
portable tube scope and just too well made to ever scrap,
IMHO. For example it opens up like a car hood to give
access to the entire centerline of the box, with components
on both sides of the hinge. The reason Why I opened it is
that it reliably blows fuses on power-on. All looks perfect,
no burn marks or damage anywhere, just a little dust.
My thinking is that its the old electrolytic capacitor thing.
There are about 5 large (2"x3") and more smaller ones
present. Do I just cut the leads and test-form them to see
if they hold a charge or is there some other obvious thing
to start with?
I probably shouldn't ask before the holidays,
but it might be worth a try.
John A.