One possible issue with replacement lamps is the presence or otherwise of radioactive material in the lamp. Many glow lamps (and gas filled voltage regulators) have radioactive isotopes added to the gas fill or electrodes to maintain a low level of ionisation when "off" and thus allow consistent triggering. It's particuarly relevant to lamps that are kept in the dark such as these choppers (light also helps triggering). The amount and type of isotope used can vary even with the same part number and maker, depending on what was available (or cheap) at the time and place of manufacture. Another issue is that all radioactive isotopes decay, some more quickly than others. Krypton 85 was sometimes used as a fill gas additive and has a half-life of about 10.75 years. so after 21.5 years only a quarter of the activity is left. This could cause a NOS lamp not to function as expected. So if there is a known good batch / brand it's worth sticking with. In case you haven't guessed, I'm also a radiation nut.
Robert G8RPI. ________________________________ From: Charles Black <cbl...@centurytel.net> To: Discussion of precise voltage measurement <volt-nuts@febo.com> Sent: Thursday, 7 November 2013, 0:12 Subject: Re: [volt-nuts] Fluke 845AB / 845AR neon bulb xref Hi Christopher, I used some look alike NE-2's from ebay and they worked fine. Just search for ne2. Good luck! Charlie On 11/6/2013 2:34 AM, Christopher Brown wrote: > So, working on a couple of 845s. > > The AR is a franken unit assembled from the parts of 2 damaged units. > > Works well, but intermittently, both neons are very weak. > > The AB was working well after cleaning up the leaking battery mess, and > recapping but one of the bulbs failed. > > > Looking at the original manual and a 1990 update I get > > NE-2U > > AND > > Lamp, NEON, 105-125V, 0.7MA, Wire Leads A9A-1 > > > Cannot seem to find direct or xref > > > Mouser show a Chicago Miniature A9A but no A9A-1 and A9A is 65VAC/90VDC > > > NE-2U seems to cross to A3C, but cannot find A3C and A3C specs seem to > indicate 1.9ma > > > Can anyone help with the correct spec, xref to current part and supplier? > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > > _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
