Oops... Forgot to add something...
For the uninitiated, the "blue glow" is not necessarily bad. That being "Bad"
is highly dependant on the tube/valve in use. For
instance, I have yet to see certain types of them that didn't have a glow
between the electrodes, take a converter for instance [6A8
series, among others]. The glow doesn't indicate a gaseous condition, but in
fact indicates normal operation. Mercury-vapor,
regulators, etc, will also glow.
Remember, this is 2001, there are many uninitiated out there that could take
such statements literally to mean ALL such tubes/valves
with a glow are bad, when they are not. There are probably many on this list
with little or no experience with receiving tubes or
low-power transmitting tubes. I'm 33, and there are probably many more that
are younger on this list.
I know where you are coming from, because I restore old tubed radios, but that
doesn't mean the next guy will.
Peter Chadwick wrote:
>>Don't go destroying tubes for these unless you have
>>verified their death on a calibrated tube tester of adequate quality [TV-7,
>>
> etc]
>
> You don't need a tube tester to find an open circuit filament/heater, or
> shorts
> present when cold. Blue glow in the space between electrodes is a pretty good
> indicator of gas, too. I've never actually found enough requirement for a tube
> tester to make its acqusition worthwhile. If I'm building something from
> scratch
> and am doubtful about a tube, I'll make a jury rig on the bench and check
> currents and transconductance. The amount of time that I have spent on that
> over
> the years is so miniscule that investment in a tube tester isn't worthwhile.
>
> If you're servicing some gear, replacement is a good start. I haven't yet met
> anything that was critical as to the brand of tubes - unlike some sand stae
> gear, where I've known of designs that would only work with one manufacturers
> brand of op amp!
>
> 73
>
> Peter G3RZP
>
>
>
>
> --
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jim
--
ET has one helluva sense of humor!
He's always anal-probing right-wing schizos!
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