If your tubes are socketed (assuming they are, because they re IN-18), it's probably best to run them from a separate supply. If your supply has current-limiting, this is easy: Just set the voltage higher than the ionization voltage of the tube (around 160-180), then increase the current to the desired level. Be careful removing/inserting IN-18's; they have soft pins that are easy to bend and it probably doesn't take much more to break them.
If you dont have current-control on your power supply, add a series resistor. A rough starting value would be about 3K for 10mA, and adjust voltage accordingly. Be sure to monitor the current periodically, because it's possible that as the tube rejuvenates, the current could increase. Also be aware of the power rating of the resistor; 1/4 W will probably fry. You can calculate the required power (P=I^2 * R) easily. If your tubes cant be removed, boosting the supply voltage by a few volts is unlikely to be enough to get high enough current for depoisoning (around 3x to 4x nominal current). If the driver is current-limited, boosting the supply voltage will have no effect. If there's an anode resistor, you could put another one in-parallel with clip-leads to increase the tube current, but you need to be careful. Make sure you know the values of the resistor in the clock, and the one you are adding in-parallel. Calculate their parallel resistance (R1*R2/(R1+R2) and measure the voltage across it to determine the current. Personally, I've had very little success trying to recover the few bad nixies I have (all are 5031); my conclusion is they have leaked over the previous 50+ years, so no amount of high-current operation will help. Best of luck; let us know if you were able to recover your tubes. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/1d5e7358-7733-455e-86f6-3f26d96965be%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
