03-20-2015, 01:26 PM
Audio section, now pretty much complete. Just need to make a permanent connection where that clip lead is.
Remote receiver section. Recap complete, but still doesn't seem to get signal through the first amp tube.
RF section. Recap complete. This one was fun, with the shields in place.
Now for the rest: Audio section had several bad resistors, as in completely open. The cathode resistor from the phase splitter was open. The grid leak resistor on one of the outputs was also open. Add to this, the junction of the grid resistors was never reconnected to the B- supply. (how in the h-e-double-toothpicks did this beast sound as good as it did?!?!?). Once all of the caps were replaced, all this other stuff started showing up as severe distortion in the output. Yuck. Back to sounding pretty good now, with more power.
OK.. so there's yet another issue. Whomever let out the magic smoke from the original power transformer replaced it with one that does not put out the requisite B+ voltage. The output of the rectifier should be 345V, but is more like 260V. This not only gives inadequate B+ for the radio to perform to spec, it also fixes the B- at too low a voltage to properly bias the output tubes (they have only ~10.5V). Not at all sure what to do about this.. finding a proper transformer may be quite a challenge.
Remote receiver section. Recap complete, but still doesn't seem to get signal through the first amp tube.
RF section. Recap complete. This one was fun, with the shields in place.
Now for the rest: Audio section had several bad resistors, as in completely open. The cathode resistor from the phase splitter was open. The grid leak resistor on one of the outputs was also open. Add to this, the junction of the grid resistors was never reconnected to the B- supply. (how in the h-e-double-toothpicks did this beast sound as good as it did?!?!?). Once all of the caps were replaced, all this other stuff started showing up as severe distortion in the output. Yuck. Back to sounding pretty good now, with more power.
OK.. so there's yet another issue. Whomever let out the magic smoke from the original power transformer replaced it with one that does not put out the requisite B+ voltage. The output of the rectifier should be 345V, but is more like 260V. This not only gives inadequate B+ for the radio to perform to spec, it also fixes the B- at too low a voltage to properly bias the output tubes (they have only ~10.5V). Not at all sure what to do about this.. finding a proper transformer may be quite a challenge.
