Tech Help: 0A2 Tube Test Settings
Corvette Bob
I'm working on a Seeburg AY100U and want to test the 0A2 voltage
regulating tubes in a Hickok 6000A tester. Unfortunately, there is no
0A2 settings on the chart. Just a 0A4 which I don't think is a
substitute. Thanks for any help you can provide.
Bob
John Robertson
Hi Bob,
You can test the OA2s in circuit - if you show are 150VDC across each
tube then they are good. They also glow purple when working correctly.
These tubes rarely fail, but if they were to fail they would either
short - I've never seen that - or they get gassy, again rare, (or they
loose vacuum completely) and then they would arc and spark and be rather
obvious that they are sickly.
If you want to check them out of circuit then you need a power supply
that can provide at least 175VDC (to turn on the OA2) - be sure to have
a few hundred ohm resistor in series with the supply to act as a current
limiter.
If you have a tube book you can check if the OA4 and OA2 are similar and
what differences exist - then see if you can adjust your tube tester
accordingly.
John :-#)#
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John Robertson
According to this web site:
http://evatco.com.au/webcat1p10.htm
The OA4 looks like it is a 300VDC tube, of no use to Seeburgs! However
if your tester checks OA4s then it should be adjustable to handle the
OA2s. Do a search online for your make and model of tube tester aling
with OA2 and see what turns up...