[Radio Wrangler]

I've repaired several Mitsubishi transmitter modules.

The radios have no protection. You can just keep transmitting until the heat kills the module.

The ceramic substrate cracks, breaking several conductors. Sometimes a module works when cold and stops working once it has raised in temperature.

I used fine tinned copper wire and solder across the breaks. One needed a new diode, so I used a wire-leaded one which I thermally linked to the substrate with silicone grease.

You need a small but powerful soldering iron like a Metcal with various bits. A stereo microscope makes it easier.

These radios long ago used up the stocks of real spare modules. It's unlikely that you found a real one that had been overlooked.

David