03-13-2013, 12:35 AM
All caps in this circuit are new (when I recapped 5 years ago.) I left a couple of original micas elsewhere, but not here. I also replaced all the rubber wiring.
When I started this thread I pulled off one lead of each cap and resistor T A Forbes suggested and tested for leakage with a vacuum tube capacitor tester at 600 VDC for the polys and 500 for the mica. None leaked under that test, so I reconnected them. Like I said, the current through the resistor is steady at about .4 ma, dissipating about .08 watts. It is a one watt resistor, and it's cool to the touch after running a while.
Just for fun I put replaced the burned one with 2 resistors in series (a 2200 ohm and a 2400 ohm to give 4600 ohm) to effectively make a 2 watt resistor, and I ran the radio for hours and hours over a couple of days monitoring voltage drop, current, and temperature (by the finger method). Everything was dead on every time I checked it, so I'm pretty satisfied that I might have burned the resistor by touching something wrong with a meter lead or something silly like that when I recapped and tested the the thing a long time ago.
I do remember that when I got the radio somebody had totally bollixed it trying to recap & rewire it before I got it. A lot of wiring was missing or just wrong. I made some mistakes trying to straighten our his faulty wiring (gave me fits for a couple of weeks because I had to figure out routing and connections without referring to the original) so maybe I did something to stress that resistor when I was working on it. I just wanted to ask you guys if I'd missed something essential.
Thanks, Gary, Ron, Codefox, and TA Forbes for your responses.
When I started this thread I pulled off one lead of each cap and resistor T A Forbes suggested and tested for leakage with a vacuum tube capacitor tester at 600 VDC for the polys and 500 for the mica. None leaked under that test, so I reconnected them. Like I said, the current through the resistor is steady at about .4 ma, dissipating about .08 watts. It is a one watt resistor, and it's cool to the touch after running a while.
Just for fun I put replaced the burned one with 2 resistors in series (a 2200 ohm and a 2400 ohm to give 4600 ohm) to effectively make a 2 watt resistor, and I ran the radio for hours and hours over a couple of days monitoring voltage drop, current, and temperature (by the finger method). Everything was dead on every time I checked it, so I'm pretty satisfied that I might have burned the resistor by touching something wrong with a meter lead or something silly like that when I recapped and tested the the thing a long time ago.
I do remember that when I got the radio somebody had totally bollixed it trying to recap & rewire it before I got it. A lot of wiring was missing or just wrong. I made some mistakes trying to straighten our his faulty wiring (gave me fits for a couple of weeks because I had to figure out routing and connections without referring to the original) so maybe I did something to stress that resistor when I was working on it. I just wanted to ask you guys if I'd missed something essential.
Thanks, Gary, Ron, Codefox, and TA Forbes for your responses.
John Honeycutt
