Frozen cores in transformer

[jtrouter]

Hello
I am trying to help a friend, I know i read a post a maybe a month ago about how to release a tunable core that is stuck.
We know how easy they snap and he is restoring a FT101EX not that the radio is relevant. SO if anyone can help with the best
way to get this loose please respond and meanwhile i will keep searching. Thanks

 

[nomadradio]

If the core is cracked, this gets messy. If the core cracks, turning the tool makes the core expand inside the coil form. Kinda like the centrifugal clutch in a go-kart. Breaking the core into pieces is the only way I know, besides replacing the coil outright. But then you need a proper replacement. The 'recipe' used to make coil cores depends on the frequency of the circuit in question. They are not all equal, and they bear no identification to distinguish one from the other. This method still leaves you needing a new tuning core, and it has to be the right one. Like, coming out of the same-type part.

Most-efficient solution is to find a junked unit to serve as the organ donor, and do a transplant.

A radio as popular as that one will have chop shops on fleabay, buying radios and parting them out. Might get lucky and find the coil you need there.

73

 

[DoctorAudio]

On many IF transformers the threaded hole goes clear through. When this is the case you can remove the transformer from the PC board and you will see the adjustment slot on the bottom end of the core. 9 times out of 10 the bottom end of the core isn't cracked and you will be able to run the core out the end.
But as Nomad said, you still need a core with the same characteristics to replace the cracked one.
In a pinch where I couldn't find a donor core, I've carefully cleaned out the threads of any broken core particles, solder the IF transformer back onto the board, then carefully twist the old core into the transformer broken end first so the non-cracked end is up and carefully tune the circuit.

 

[Shadetree Mechanic]

Is this one of the radios that have the slugs glued into the cans?

 

[nomadradio]

slugs glued into the cans?

No, but there is a row of them with wax securing the slugs. It's a bandpass circuit that typically never needs attention.

73