[Tubejunke]

Ok, since these old units are steadily gaining popularity as anyone can see that has been watching the prices go up considerably in the past year or two, we may as well have some good reference posts for others that wind up getting their own although they will more than likely be a Heahkit or Sprague. So I'll throw out the latest on the Knight.

A very nice gentleman that has the website that is dedicated to vintage test equipment has given me some advice and asked a few questions. One question was that he wanted to know what current was across the cap test terminals when the unit was set for electrolytic testing and eye closed; voltage applied was 50V and my Variac powered the unit at 100V. I measured about 5mA and sent him my results. I haven't heard what he thinks yet, but I believe his page on this unit says 5 or so mA is the magic number.

So I'm still dead in the water with the original problem and thus far no solutions. I even replaced the .25mfd 400VDC cap right beside the leakage switch. My Heathkit IT-28 showed this cap to be leaking at pretty low voltages, however my C3 didn't show the cap as leaky until I was in hundreds of volts. Either way it leaks, but a new replacement cap made no difference. This could be another thread!

Just out of curiosity I decided to hook my ammeter in series with either open leg of an electrolytic cap and see what I get first on a known good C3 and then the Knight. The C3 proved to show and expected initial rise in current when voltage was applied via the leakage switch; followed by a steady decline as the capacitor charges, followed by almost no current flow when charge is complete. NOW, I go to the Knight and I get a completely different reaction. I get first a small amount of current and then a not so slow sharp rise in current. It will be interesting when I find out what this devil is doing, but that sure isn't what I want it to do