Capacitor Choke - Printable Version
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+--- Thread: Capacitor Choke (/showthread.php?tid=26026)
Capacitor Choke - Jeansonne - 09-29-2025
Just starting to recap this 42-358 code122 and I run into this problem. It seems to be a .2 mfd capacitor with about 7 wraps of wire around 1 end. When I ordered my new capacitors, I didn’t order one because the parts list didn’t call for a .2 mfd capacitor. I’m thinking this is Part No. 17, which shows to be a condenser and r. F, choke, in the “locations of parts-under chassis”. Took a picture but not sure if it posted.
So what is this and where do I get one? Or do I have to make one. It looks homemade using a 2 mfd Philco capacitor part no. 30-4594.
RE: Capacitor Choke - morzh - 09-29-2025
It is the link that connects chassis to Ground.
Not really critical. To keep the geometrry, you could restuff the cap with the identical capacitor, and then replicate the winding, which is super-easy.
But if you skip the winding, nothing bad will happen anyway.
RE: Capacitor Choke - MrFixr55 - 09-29-2025
+1 on Morzh's answer. This cap connects B- to the chassis capacitively This is so high frequencies are conduced but ow frequencies are limited. This cap is the difference between the radio being a "warm" chassis vs a hot chassis. Definitely change the cap. The external coil is certainly optional I have never seen this winding on the same coupling cap used in RCA, Emerson or other AA5 type sets.
RE: Capacitor Choke - Arran - 09-29-2025
With some of these Philco actually used a bobbin to wind the choke coil on, and slipped it over the capacitor, in this case they just wrapped some 20 awg wire around the outside body of the cap. You can replicate the coil easily enough by cleaning out the old cap shell, and wrapping some bell wire around it, then inserting the new 2.2 uf cap on the inside. I honestly don't know if these make any difference these days, I think that they were a wave trap designed to block marine beacons, or something else, from getting into the set
Regards
Arran
RE: Capacitor Choke - morzh - 09-30-2025
Yes, only the cap is 0.2uF and not 2.2uF.
I guess this makes the touch current a tad less lethal...though it is still lethal
