Yep, just about one "step" on the filament select switch! :-)
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
Robert Ladden wrote:
That got me wondering how much the life test drops the filament voltage. I put a 6JB6A in
my tester and measured the filament voltage. The tester's "normal" 6.3V was
really 6.2V. The life test dropped it to 5.6V. On a 12AX7 it dropped from 12.7V to 11.6V.
So it only drops the voltage about 9%.
73,
Bob WW3QB
--- On Sun, 1/31/10, Garey Barrell<[email protected]> wrote:
From: Garey Barrell<[email protected]>
Subject: Re: [Drakelist] What circa tube tester?
To: [email protected]
Date: Sunday, January 31, 2010, 11:41 AM
Bob -
That's a very good site reference. Lots of good
information there.
The "Life Test" typically just reduces the filament voltage
on the tube. This indicates whether the cathode is
straining to deliver enough electrons, (wearing out,) or has
"life" left! If the meter indications stays steady or
only drops slightly, then the tube has considerable life
left, at least from an emission standpoint. If the
meter drops a lot, not good.
You can perform a similar test on any tube tester, merely
switch the filament voltage DOWN one step, i.e., from 6.3 to
5 volts. A "good" tube will drop only a few divisions,
while a "weak" one will drop 5 to 10 or more divisions.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement
CDs
_______________________________________________
Drakelist mailing list
[email protected]
http://mailman.zerobeat.net/mailman/listinfo/drakelist
