01-22-2014, 10:14 AM
Good chance this beauty blared out ".. a date which shall live in infamy...", being one of the last sets put out before we entered the war.
This one drove me a bit crazy(er) for a while. Hooked it up to a D cell and 90V DC and all I got was a pop. Looked at the current draw and the DC supply meter was pegged, over 150mA.
Changed out all the paper caps (5) and the electrolytic. Nothing changed. I disconnected the B+ from the output tube, still no change. Disconnected the B+ line to the rest of the tubes, current dropped to zero. Reconnected the output tube, current now at 14mA (still seems a bit high to me, but much better).
I couldn't find any problems with the IF cans or any other shorts. I reconnected the B+ line to the IF/RF sections, back to over 150mA. I scratched my head for a bit then decided to pull the tubes one at a time to see what happened. Pulled the output first. No change on the meter. Pulled the 2nd Det/AF, still no change. Pulled the IF tube. Bingo! Current dropped to about 3mA.
When I looked at the tube, I noted that it was a 1A7: NOT the tube that belongs in that socket. Looked at the tube in the 1st Det. socket: Aha.. there's the IF tube! Switched these two around and turned the radio on YES! it works
Total current draw: about 22mA.
Just got the information download from Steve. I see that the total current draw on the B+ is supposed to be only around 7mA.. so it's drawing 3x what it should. Wonder if this means I have a gassy output tube? The sound is a bit muddier than I think it should be....
This one drove me a bit crazy(er) for a while. Hooked it up to a D cell and 90V DC and all I got was a pop. Looked at the current draw and the DC supply meter was pegged, over 150mA.
Changed out all the paper caps (5) and the electrolytic. Nothing changed. I disconnected the B+ from the output tube, still no change. Disconnected the B+ line to the rest of the tubes, current dropped to zero. Reconnected the output tube, current now at 14mA (still seems a bit high to me, but much better).
I couldn't find any problems with the IF cans or any other shorts. I reconnected the B+ line to the IF/RF sections, back to over 150mA. I scratched my head for a bit then decided to pull the tubes one at a time to see what happened. Pulled the output first. No change on the meter. Pulled the 2nd Det/AF, still no change. Pulled the IF tube. Bingo! Current dropped to about 3mA.
When I looked at the tube, I noted that it was a 1A7: NOT the tube that belongs in that socket. Looked at the tube in the 1st Det. socket: Aha.. there's the IF tube! Switched these two around and turned the radio on YES! it works
Total current draw: about 22mA. Just got the information download from Steve. I see that the total current draw on the B+ is supposed to be only around 7mA.. so it's drawing 3x what it should. Wonder if this means I have a gassy output tube? The sound is a bit muddier than I think it should be....
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