12-24-2013, 07:03 PM
Herb;
OK, I understand. I just did not know your skill level. You sound much like me. That is how I got started too. I was a teenager in high school before we had television. Dad retired and I began to learn how to repair it. I am also an amateur radio operator, although I have been inactive for a while. I need to get my tower and antenna up. I have a start on it with the first section and base embedded in concrete about 50 ft. from our house.
I just figured out my problem with the IF and detector in this set. I was feeding a modulated 455kHz signal in at the antenna input as Philco suggested and was not getting much output. I finally discovered that when I wired the first IF transformer to the IF tube socket I got the secondary and tertiary windings swapped. The tertiary winding is supposed to go to the suppressor grid and the secondary of course is supposed to go to the signal grid of the IF amp tube. After I corrected that I now have a good tone at the audio output and a strong signal to the detector circuits. I sometimes do that and make stupid mistakes. I had made a drawing and at one point I had it connected right and because I had changed the wire colors I managed to get it wrong. Now it is correct and I have a good chance of getting this set working. I discovered my mistake by making ohm meter checks. The secondary winding is supposed to be about 8-10 ohms and the tertiary winding is less than 0.1 ohms. Boy did that make a difference!
I wish you and your family a Very Merry Christmas and a Happy, Healthy and Prosperous New Year!
Joe
OK, I understand. I just did not know your skill level. You sound much like me. That is how I got started too. I was a teenager in high school before we had television. Dad retired and I began to learn how to repair it. I am also an amateur radio operator, although I have been inactive for a while. I need to get my tower and antenna up. I have a start on it with the first section and base embedded in concrete about 50 ft. from our house.
I just figured out my problem with the IF and detector in this set. I was feeding a modulated 455kHz signal in at the antenna input as Philco suggested and was not getting much output. I finally discovered that when I wired the first IF transformer to the IF tube socket I got the secondary and tertiary windings swapped. The tertiary winding is supposed to go to the suppressor grid and the secondary of course is supposed to go to the signal grid of the IF amp tube. After I corrected that I now have a good tone at the audio output and a strong signal to the detector circuits. I sometimes do that and make stupid mistakes. I had made a drawing and at one point I had it connected right and because I had changed the wire colors I managed to get it wrong. Now it is correct and I have a good chance of getting this set working. I discovered my mistake by making ohm meter checks. The secondary winding is supposed to be about 8-10 ohms and the tertiary winding is less than 0.1 ohms. Boy did that make a difference!
I wish you and your family a Very Merry Christmas and a Happy, Healthy and Prosperous New Year!
Joe
