Re: Care of Rare Valves
Turning valves like a wine bottle:
Glass acts like a super cooled liquid or like toffee. Quite a few valves from the 1920's era have been damaged by storage on a shelf on their sides in a box for 60 to 80 years without being moved.
It especially effects the ones where they are globe shaped valves without an upper mica insulator from the top anode structure area in contact with the glass. I have a few where the anode assembly slowly fell down and the distortion of the structures also caused filament - grid shorts.
So ideally vulnerable valves to this effect should be stored vertically in the gravitational field, or be rotated 180 degrees every few years.
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