Chris, You're in a real pickle. I'd say, "I feel your pain", but I've never been a fan of the 6909. I do, however, understand, that you want your instrument to be fully functional, at its full specs. I really don't know what can be done with a 6909 to extend its shelf life. To do that we need to know how they're really failing. Don't know if its from gas leaking out, or air leaking in. That way we'll what's better. Storing it under elevated pressure, or lower pressure. Cooling will probably slow down any reactions, but by how much. It may only be a few percentage points. And if we're not careful, we might accidentally introduce condensation which will corrode the wires, and the rusting wires may crack the glass seal. There are some 2 guide high speed dekatrons other than the 6909, 6910, and Z505S. I think the A103 and A106 meet that standard. They are a little shorter than the 6909, so maybe they'll work using a socket adapter. The Russians kept making dekatrons well after the west stopped. So that may buy an extra 20 years.
On Thursday, June 20, 2013 10:43:37 PM UTC-7, Chris Stephens wrote: > > some years back I found and restored a Erie Instrumation Dekatron based > frequency counter. > > http://www.xymox1.com/Projects/erie_instrumation_model_400.htm > > Its a wonderful instrument. > > Recently tho I noticed that one of the 6909 was degrading. It was getting > stuck and could not reach 100khz operation any more. I checked all the > signals to it and all were great. The tube was not performing normally. I > know these 6909 tubes have life issues. The counter uses 2 of them, one in > the 1's position and 1 in the 10's position. Swapping these brought the > unit back to normal operation and careful adjustment of voltages got be to > 100% perfect operation up to 120khz. > > However.. > > It now painfully obvious the 6909's are dying. As are all 6909's I > believe. I could alter the circuit to use 6802's but at a reduced > functional max freq of 5Khz which is a long way from its 100khz. There is > no doubt that one day there will be no more 6909's as they will all die. > > Im looking to pick up some known good, and maybe really great shape > 6909's. I need to replace 1 for sure, and then im going to store away the > others for later hoping they will last on the shelf. > > How should i store these ? If they are outgassing maybe a pressurized > container to keep the gasses in the tube ? If the odd gas is reacting with > materials inside the tube maybe placing them in the freezer might extend > life ? Maybe both, pressurized container and freezing it ? I realize these > are extremes but I REAALLY want to have working tubes in 20-30 years. Maybe > longer. > > I realize im like the only one who cares about these 6909's as I would > think no one now needs to go 100khz but my unique frequency counter. > > So maybe someone here has some nice 6909's ? and maybe you guys might know > of a way to preserve them for 30-100 years from now ? > > Also of course, as always, if anyone happens to have a manual for the > counter im VERY interested in it. > -- 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/324c89d7-10be-4688-bb3e-23c93815fe6d%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
