06-08-2013, 02:20 PM
I just got one of these in. It had many problems...
First off, a voltage divider resistor in the 1st detector screen circuit had virtually opened (9K resistor measured around 2.3M). Replacing this brought the screen voltage back from the land of ludicrous.
Second, the primaries of both the antenna and LO coils were open. When I tried to unwind a turn or two so I could reconnect them to their pins, but the coils both came off in pieces no larger than a single turn. I found the thinnest wire I had (removed from tunable loopstick) and wound about 20 turns on each coil (it's an ugly looking job, but it works). This brought the radio to some semblance of life.
The gain on the radio seems reasonably good, RF wise, for a four tube set. However, the volume does not seem to me to be up to par. It's listenable, if you're there by the radio, but room filling it's not.
I've rebuilt the bakelite blocks, and changed out any out of tolerance resistors (amazingly enough, almost all the dogbones were still well within tolerance, some within 5%!). I suspect the 2nd detector circuit is not very efficient, but one would think the set was designed more volume than a pocket radio in mind.
Are these radios normally so limited on volume? Or is there something that I've not yet found?
First off, a voltage divider resistor in the 1st detector screen circuit had virtually opened (9K resistor measured around 2.3M). Replacing this brought the screen voltage back from the land of ludicrous.
Second, the primaries of both the antenna and LO coils were open. When I tried to unwind a turn or two so I could reconnect them to their pins, but the coils both came off in pieces no larger than a single turn. I found the thinnest wire I had (removed from tunable loopstick) and wound about 20 turns on each coil (it's an ugly looking job, but it works). This brought the radio to some semblance of life.
The gain on the radio seems reasonably good, RF wise, for a four tube set. However, the volume does not seem to me to be up to par. It's listenable, if you're there by the radio, but room filling it's not.
I've rebuilt the bakelite blocks, and changed out any out of tolerance resistors (amazingly enough, almost all the dogbones were still well within tolerance, some within 5%!). I suspect the 2nd detector circuit is not very efficient, but one would think the set was designed more volume than a pocket radio in mind.
Are these radios normally so limited on volume? Or is there something that I've not yet found?
