My Drake R-4B works fine but sometimes when I turn it on the OB2 tube puts
on a light show with swirling orange glow brightening up the inside of the
radio. It was kind of scary the first time I saw it. Usually when it does
that if I turn it off once or twice it stops doing that. Is this a cause for
concern? Is the tube going bad or indication of some other problem? I don't
have a spare of that tube on hand but I can get one on Ebay for not much.
Thanks.

Steve

Steve,
A bit or swirling of color as a regulator tube lights off is not
uncommon. Until the tube is in full operation and the circuit being
supplied stabilizes, the state of the gas will vary. The tube will also
"swirl" if the current is changing, as in keying up a transmitter. If,
however, the regulator tube has a defined, white flashing or arcing,
then you do have a problem. Typically, a "light-show" coming from a gas
voltage regulator in a properly designed and operating circuit indicates
a failing tube. In any case, you might want to measure the voltage
applied to the regulator tube at the time it flashes on you.
Solid-state power supplies provide B+ almost instantaneously, well in
advance of the tube circuits heating up in your receiver. It may be
that a temporary, excessive voltage is being applied to the regulator
tube, in advance of the circuit(s) being supplied are drawing current.
If that's the situation, measure the series dropping resistor's value as
it could have changed over time, downwards. Hope this adds something
towards answering your question.

de Jeep/K3HVG

Steven L Umbach wrote:
My Drake R-4B works fine but sometimes when I turn it on the OB2 tube puts
on a light show with swirling orange glow brightening up the inside of the
radio. It was kind of scary the first time I saw it. Usually when it does
that if I turn it off once or twice it stops doing that. Is this a cause for
concern? Is the tube going bad or indication of some other problem? I don't
have a spare of that tube on hand but I can get one on Ebay for not much.
Thanks.

Steve

Thanks a lot for that information. It is more a yellow/orange swirling that
an arcing white. It seems to have gone away for now. I did not fire up my
R-4B for most the summer and saw this happen today. I left it on for about
ten minutes and then turned it off briefly. After turning it on again it did
not do it anymore nor for a couple more off/on cycles. The upcoming Graylake
Illinois hamfest is always a great one so I think I will go to get a new
tube and make sure I have replacements for all the tubes in my R-4B that
usually are a buck or two there. The R-4B is one sweet sounding ham
receiver. Thanks again.

Steve KK9ZZ


"K3HVG" wrote in message
...
Steve,
A bit or swirling of color as a regulator tube lights off is not uncommon.
Until the tube is in full operation and the circuit being supplied
stabilizes, the state of the gas will vary. The tube will also "swirl" if
the current is changing, as in keying up a transmitter. If, however, the
regulator tube has a defined, white flashing or arcing, then you do have a
problem. Typically, a "light-show" coming from a gas voltage regulator in
a properly designed and operating circuit indicates a failing tube. In any
case, you might want to measure the voltage applied to the regulator tube
at the time it flashes on you. Solid-state power supplies provide B+
almost instantaneously, well in advance of the tube circuits heating up in
your receiver. It may be that a temporary, excessive voltage is being
applied to the regulator tube, in advance of the circuit(s) being supplied
are drawing current. If that's the situation, measure the series dropping
resistor's value as it could have changed over time, downwards. Hope this
adds something towards answering your question.

de Jeep/K3HVG

Steven L Umbach wrote:
My Drake R-4B works fine but sometimes when I turn it on the OB2 tube
puts on a light show with swirling orange glow brightening up the inside
of the radio. It was kind of scary the first time I saw it. Usually when
it does that if I turn it off once or twice it stops doing that. Is this
a cause for concern? Is the tube going bad or indication of some other
problem? I don't have a spare of that tube on hand but I can get one on
Ebay for not much. Thanks.

Steve