Thor61 wrote:Will 1n4007 type work ok? ...what do you think about the tester in general?
1N4007 is perfectly good for 1 amp and 1000 volts. The reverse voltage calculation is funny - the diode will see roughly 2 * sqrt(2) * 260VAC, or about -730 VDC. This is within the parts rating, so it will be fine. You'll start to run into trouble once the PT goes over about 350VAC (or 700VCT for a full wave supply). They do make parts with high PIV ratings, but they start to get expensive. For some applications, the
Fairchild ISL9R8120P2 is suggested. It's rated 1200PIV @ 8A.
I usually buy UF4007 because they cost only pennies more than 1N4007, and they switch faster (are quieter). This property is useless in a tube tester application, but is nice to have in an audio amplifier's power supply. By the way, the Fairchild part suggested above switches even faster than a typical UF4007.
If you need more than 1 amp, you can use a 1N5408. They're cheap and good for 3 amps, but you don't need it here.
The tester looks like "just" a simple emissions tester, verifying reasonable cathode currents at a fixed operating point. It's certainly a reasonable way to cull out the obvious losers. I'm sure you could pay more and get a less useful tester taking your chances on some vintage piece of equipment from eBay.
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