B-5971 question

[Frédéric Vecoven]

Hi.

I got lucky in finding 8 "NOS" B-5971. I tested them, 4 are perfect, but the other 4 don't show any sign of life. I have been using 170V (up to 180V) and a 10k resistor. Since I don't want to damage these rare tubes, I wonder if I should try some higher voltage/current, to see if the 4 dead tubes are doing better.

If they out-gased, is there a method to detect this ? (I mean some method to ionize the neon)

I may not be interested in keeping these tubes, so if folks are interested, let me know. I may trade them too (looking for ZM1040)

-Fred

[Dekatron42]

You can hold them close to a plasma ball and they will ignite if there is neon in them (or other gases in them too), just hold them with your hand and let them touch the glass of the plasma ball. If you compare the glow of a known working tube and one that you think is leaky you will hopefully see any differences in how they glow.

/Martin

[John Rehwinkel]

> I got lucky in finding 8 "NOS" B-5971. I tested them, 4 are perfect, but the other 4 don't show any sign of life. I have been using 170V (up to 180V) and a 10k resistor. Since I don't want to damage these rare tubes, I wonder if I should try some higher voltage/current, to see if the 4 dead tubes are doing better.

Try higher voltage but the same current (in other words, increase the anode voltage, and also increase the anode resistor).

> If they out-gased, is there a method to detect this ? (I mean some method to ionize the neon)

Martin's suggestion of a plasma sphere or similar (fluorescent lamp tester, hand-held spark coil, etc.) is a good one too.

- John