Yes, I'm switching both the EHT and the heater. I would be surprised if cathode stripping is an issue considering the very small beam current in a CRT compared to, say, a power amp tube. Keeping the heater warm is a form of soft starting. I did that in my E1T clock where it starts from cold with about 60% heater voltage applied and then full HT and heater volts kick in about 10 seconds later.
Morris On Sunday, August 10, 2014 7:07:18 PM UTC+10, Sgitheach wrote: > > > Morris > > Are you switching off the HT/EHT to the tube when the heater is off as > well? My understanding is that it is not good to switch the heater on > while there is full HT on any thermal valve/tube. > > You might take the opportunity to "soft start" the CRT heater - I can PM > you a schematic I'm using if you wish? > > Cheers Grahame > > On 10/08/2014 10:00, Morris Odell wrote: > > Hi all, > > Latest progress on the Sperry radar clock - I found a very helpful > transformer manufacturing shop whose owner was happy to vacuum impregnate > and bake the howling transformer for me. Alas, it only made a very small > difference, if any. It sounds like the problem is magnetostriction in the > core so there's no easy solution. I've rubber mounted it to try to stop the > rear chassis panel from acting as a sounding board but that's all I can do > I think. Hopefully it will be quieter when it's all buttoned up. > > Right now I'm working on a PCB which will contain a PIR motion detector > and also a Xbee wireless receiver to pick up the GPS data that I have sent > around my house. > > I also have a question - among other things the PIR motion detector > switches the power to the CRT heater. Is it worth dribbling a little bit of > current through the heater when it's off so that it heats up faster when > the PIR senses an observer? If so, how much? The CRT heater draws 300 mA at > 6.3 volts when it's working but takes about a minute to get to full > emission. Will preheating it like that shorten its life significantly? > > Any opinions much appreciated, > > Thanks, Morris > > > > On Monday, July 14, 2014 7:02:47 PM UTC+10, Morris Odell wrote: >> >> Hi all, >> >> I've got the clock displaying time now. The video shows it upside down on >> the bench so it's at a few minutes past 12. That howling power transformer >> is a distraction, I'll have to wrap it in some sound absorbing material >> especially as I like to add Westminster chimes to my clocks :-). >> >> The next step is to put it all together and tidy it up! >> >> https://www.youtube.com/watch?v=tL3840bE9Cs >> >> Morris >> >> >> >> >> -- > 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] <javascript:>. > To post to this group, send email to [email protected] > <javascript:>. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/99d0f7d2-28a1-41d6-8d57-c959754607fb%40googlegroups.com > > <https://groups.google.com/d/msgid/neonixie-l/99d0f7d2-28a1-41d6-8d57-c959754607fb%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > > > -- 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/ad8e2653-d279-4581-b017-3c95c7129885%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
