Philco model 38 code 121 not receiving signal. - Printable Version
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+--- Thread: Philco model 38 code 121 not receiving signal. (/showthread.php?tid=25743)
RE: Philco model 38 code 121 not receiving signal. - GarySP - 04-27-2025
Save the money on the Kapton tape. Just cut an insulator to size out of a clear plastic blister pack and attach it around the coil tube with a small piece of cellophane tape. Take care, - Gary
RE: Philco model 38 code 121 not receiving signal. - MrFixr55 - 04-27-2025
You should be able to inject an audio signal such as from a CD or mP3into the radio at the volume control. The set will be quite loud. With a B+ of 135V, he output of a 19 will be about 2 Watts, but Class B is not as clean as Class A. However, the typical 1.5V / 90V battery set develops only about 0.2 W, only 1/10 the amount that this one will
RE: Philco model 38 code 121 not receiving signal. - Stormlord5500 - 04-28-2025
Sounds good Gary I'll do that. I have plenty of stuff like that I can scrounge up. I am still kind of new to all this so I'm not sure what alternative materials are good options.
I will say that original cellulose stuff has gotten so brittle I was easily breaking chunks off. I noticed where it had turned brown it was brittle and the wire was corroded.
I have a bunch of solenoids around that I'll never use so maybe some of them may have 44 awg wire I can use.
RE: Philco model 38 code 121 not receiving signal. - Stormlord5500 - 04-28-2025
Unfortunately I can't inject any audio into the volume control. It is in the primary circuit of the antenna coil, not in the audio section.
RE: Philco model 38 code 121 not receiving signal. - Stormlord5500 - 04-30-2025
Good news everyone! I think I have found everything I need for rewinding the antenna coil primary.
I found some plastic sheeting. What kind or what is was for I don't know. I measured the wire on this solenoid and it was on par. With some clear nail polish as the dope, we should be off to the races. What do yall think?
RE: Philco model 38 code 121 not receiving signal. - David - 04-30-2025
Good luck next thing you know you will be winding coils just for the fun of it. David
RE: Philco model 38 code 121 not receiving signal. - Stormlord5500 - 04-30-2025
Well why not!
RE: Philco model 38 code 121 not receiving signal. - Arran - 04-30-2025
As long as the plastic sheeting isn't too thick, I think that the thickness of photographic film would be just about right, if you have any strips of that laying around, some PETE plastic used in food packaging would also work. Fortunately it's a small winding so the solenoid probably has more then enough on it's bobbin, if the gauge is the same. On an antenna coil it's not really that critical, on an oscillator coil the gauge, and number of turns is critical. Usually when I find a bad antenna coil, and this has happened more then once on a battery radio, it's because of a lightning strike, and the coil is burned to a crisp, they are also typically smaller on sets from the 1940s.
Regards
Arran
RE: Philco model 38 code 121 not receiving signal. - Stormlord5500 - 04-30-2025
Thanks Arran. Yeah this plastic is pretty thin. It's a little thinner than the original stuff. It kinda reminds me of photo or movie film. I'm pretty sure I'll have enough wire and alot extra. The "Green Death" sure did a number on this poor coil. I unwound it and as soon as I got to the green area you could see the corrosion just ate the wire away. So thin in some spots it just fell apart with little effort.
RE: Philco model 38 code 121 not receiving signal. - Stormlord5500 - 04-30-2025
Well here it is. It ain't pretty, but hopefully it'll work.
I checked it with my DMM on continuity and it keeps and reads around 4 ohms. I think it might work.
RE: Philco model 38 code 121 not receiving signal. - radiorich - 04-30-2025
Hello Stormlord,
Well done on rewinding that coil it turned fairly good for your first one.
Sincerely Richard
RE: Philco model 38 code 121 not receiving signal. - Stormlord5500 - 05-01-2025
Thankyou for the kind words sir.
I double checked it with my component tester and it read 2.7 ohms at .02mH.
RE: Philco model 38 code 121 not receiving signal. - Stormlord5500 - 05-01-2025
I think this thing is way more accurate than my Walmart DMM.
RE: Philco model 38 code 121 not receiving signal. - RodB - 05-01-2025
Yes, Walmart, right up there with Fluke.
RE: Philco model 38 code 121 not receiving signal. - Stormlord5500 - 05-01-2025
I've reinstalled the coil. Now IT'S ALIVE!!!!!!
I fired up my TinySA on signal generator mode and set it to 1400Kc and used the antenna attachment and brought it near the long wire I have hooked to the chassis and I got a little tone. I fooled around with the dial and then peaked the oscillator then antenna trimmer and she's going full steam ahead! I then used my AM transmitter to pump some music through and it sounds pretty good.
Either the volume control is dirty or worn out because when I mess with it the signal drops out and comes back and it'll go low signal then you touch it it'll pop and scratch and come back. I also have to clean and somehow mount my "new" speaker and transfer the OPT to it.
I call this a success and I thank you all for your encouragement and help.
