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Old 7th Jan 2015, 2:25 pm   #26
kalee20
Dekatron
 
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 7,061
Default Re: Rejuvenating Magic eye Valves?

I wonder if heating them could actually be counter-productive?

I was thinking, putting in an oven would take ages to get the target up to temperature, it being in a vacuum, supported by insulating mica, so why not get it to self-heat by switching on? 250V at a couple of mA gives 500mW dissipation on the target itself, which being fairly small is going to get hot. Then I thought, perhaps this is what helps kill the phosphor? Types with the phosphor on the inside of the glass, which therefore running cooler, last longer, as observed in earlier posts. And the little DM70, with phosphor on target BUT only 90V at a few hundred µA again seems to last very well.
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