Re: The "Sussex" Homebrew Valve Tester.
I have had quite a few PM enquiries recently about sourcing thumbwheel switches.
I got mine from Electrovalue, a fine place for odds and sods of surplus stuff. But I cleaned him out and he says he definitely has no more. The ones I had made up only 3 or 4 sets. All I have left is a lot of end-cheeks!
For reference they are about 2.25" square and have very wide-spaced tracks on the pcb. The action is rather jerky and stiff but at least they click positively into place.
I have yet to test them on higher heater currents but they look fairly meaty.
For anyone new to thumbwheel switches it's worth noting that virtually all currently available (surplus) switches are BCD coded (binary, 4-contact) not decimal, which is useless. Make sure you see a full set of 10 contacts on the back, plus common.
Contacts marked 1,2,4,8 instead of 1,2,3,4... are a giveaway of the BCD type.
If I find a good source of big switches I will post here.
All the best
Jeremy
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