I had a bit of an accident with my converted 6m SB-220 (flashover somewhere while transmitting, not sure where yet) that resulted in all the rectifiers in the operating bias string (Harbach rectifier
Im not a fan of that HV board and recommend rebuilding the original with 1N5408's (drill out the holes) and adding the 1N5408 bias diodes on perf board. The metering resistors can be 5M 7.5KV Ohmites
ORIGINAL MESSAGE: REPLY: A couple of options: 1. Install a 50 watt stud-mount type zener. Part numbers 1N3305-1N3350 and 1N4549-1N4556. Browse the Mouser catalog for the needed voltage. About $10 eac
Thanks for the ideas, Bill. OK, so let's say I want to clean this amp up once and for all. No more accidents. For the bias string, I'm going to go with the 1N5408 diodes I already have, which have a
ORIGINAL MESSAGE: REPLY: Wirewound is fine as they have a very large tolerance for surges. If you can physically fit in a resistor even larger than 30 watts I would suggest you do. The cost is not mu
I have several HT packs for 3-500Z, 8877 and 4CX1000A amps. All my HT packs have a glitch resistor that is 25R @ approx 70W comprising 4 x 100R 17W wire-wound resistors in parallel. I use the ones by
ORIGINAL MESSAGE: REPLY: Wirewound is fine as they have a very large tolerance for surges. If you can physically fit in a resistor even larger than 30 watts I would suggest you do. The cost is not mu
Carl, the rectifier diodes that fused short were 2.5A (251Ds). I have more questions: (1) One of the other destroyed components in the bias path was a small SPST relay that I used to bypass the 50Koh
Carl, the rectifier diodes that fused short were 2.5A (251Ds). I have more questions: (1) One of the other destroyed components in the bias path was a small SPST relay that I used to bypass the 50Koh