02-13-2024, 07:16 PM
Hello all
It's been awhile since my last post. Finally have time to get back to my7 radio bench
I am currently working on a philco model 71 code 121.
As expected it has a bad oscillator coil
I replaced the electrolitics and brought it up monitoring the current which was within what was specified.
I put a modulated IF signal through it and all as ok. Loud tone with volume control so everything is ok prior to a complete recapping.
I have a question as to rewinding the coil. It’s a small winding. Not sure where to start. The coil wire falls apart trying to unwind it. It is very fine wire wrapped around a cotton thread. I have replacement wire that is close to the same size but slightly thicker. I plan to measure the width of the winding and wrap it close to that dimension. I doubt the frequency of the local oscillator will be correct. Can I bring the spread in using the existing adjustments for the oscillator adjustment or will I have to start changing parts in the oscillator circuit. Has anyone else tried this?
Thanks
Tom
It's been awhile since my last post. Finally have time to get back to my7 radio bench
I am currently working on a philco model 71 code 121.
As expected it has a bad oscillator coil
I replaced the electrolitics and brought it up monitoring the current which was within what was specified.
I put a modulated IF signal through it and all as ok. Loud tone with volume control so everything is ok prior to a complete recapping.
I have a question as to rewinding the coil. It’s a small winding. Not sure where to start. The coil wire falls apart trying to unwind it. It is very fine wire wrapped around a cotton thread. I have replacement wire that is close to the same size but slightly thicker. I plan to measure the width of the winding and wrap it close to that dimension. I doubt the frequency of the local oscillator will be correct. Can I bring the spread in using the existing adjustments for the oscillator adjustment or will I have to start changing parts in the oscillator circuit. Has anyone else tried this?
Thanks
Tom
