On Sat, 2022-02-05 at 20:48 +1100, Julien Goodwin wrote: > I /think/ it's using more power than it did before (right around 20W > at > total cold, dipping to 10W after a while), although silly me didn't > make > a note of it, but even after 30 minutes it's not locking.
I don't have any experience with this brand/model, but I have resurrected some "dead" rubidium standards. I'm mostly going from experience with gas lasers, but I found the same approach worked on the rubidium units that I have here. It's well worth being patient with the lamp, if it's been off for many years, it may have a gas pressure/mix that's far from optimal. If you let it sit with the heater and exciter running, it may just strike after a while. (You should measure the current going into the exciter, it should jump up suddenly when the lamp strikes. Measure the unlit condition with the lamp cold and the exciter on. On mine, the current roughly doubles when it is lit.) If it does strike, keep it running for a few days, don't power it off. It can get even harder to light, before it gets easier again. You might consider using a UPS for this procedure, as Murphy could strike just after the lamp does! On one of my units, I had to manually run the lamp heater to a higher than normal temperature, before it would light. (With a thermocouple, it's best to use some heatsink grease, otherwise the readings can be a long way off.) The needed temperature gradually came down, until the unit could be reassembled and used normally. On another, I just waited for several hours at the usual temperature, and that was enough. Although again, it took a couple of days of operation before it would light without hesitation. On yet another unit, the lamp would light normally, but the photodiode signal was too weak to achieve a lock. (The firmware said nope.) So I just left it running overnight, and then after a power cycle, it locked immediately! So I wanted to point out that if the lamp has everything it needs, and still won't light, you might just need to leave it powered for a while. And you have not much to lose, if you need to run it at a higher temperature for a while. Have fun, Darren _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there.
