Replace a 28A RF Coil

An interview with Mike Morrison

Replacing T-25 oscillator coil

What was wrong with the radio?

There was something wrong with band one. It was just dead, not even a little static. Everything had been recapped, tubes checked and all resistors checked so I know this was all good.

While I had each section of the RF deck torn apart, I thoroughly cleaned the band switches and made sure every contact was making contact.

So when it came down to a band not working, there was only one thing left: make sure I dont have a open winding so I ohm out all the coils and there was an opened winding on the oscillator coil T-25.

Then what?

I was unable to find one at first so I tried rewinding it my self and not having the specs on it made it difficult and lets say I'm happy I found one (Thanks Mickey).

Replacing was a peace of cake. Disconnect all wires to coil, remove the 3 screws that hold down that board with the 3 coils, then lift up on the outer edge of that board and you should have enough room to stick your finger in there and find the screw right under the coil.

But if you need more room, the trimmer on the top of that board C103 has a wire that goes straight to ground and it can make things tight. De-solder that and you should have more room.

Back to the coil... while pushing on the screw with your finger unscrew the coil but dont let go of the screw then just screw on the new coil.

Put the 3 screws back in the board solder on your wires and align the band.

Peace of cake

Thank you

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Last modified: Monday, 5 Oct 2026