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Yep.
Unless the radio has been already damaged by the AC input.

EDIT/IIRC:
If the mic is causing self-oscillation ('squealing'); it happens because of two main reasons - if the mic is wired correctly.

The first is that the mic element/mic wire is shorted to ground inside the mic. Since some impedance for the radio is needed by the mic - and because a shorted audio wire offers no resistance/impedance - then the radio will oscillate ('squeal').

The second might be caused by stray RF getting into the mic itself when keyed. Using a disc capacitor across the mic terminals (don't remember the right value ATM) can trap the RF.

I would just check the mic wiring for starters; and then go from there . . .

[QUOTE="Robb, post: 375499, member: 8446"] Yep. Unless the radio has been already damaged by the AC input. EDIT/IIRC: If the mic is causing self-oscillation ('squealing'); it happens because of two main reasons - if the mic is wired correctly. The first is that the mic element/mic wire is shorted to ground inside the mic. Since some impedance for the radio is needed by the mic - and because a shorted audio wire offers no resistance/impedance - then the radio will oscillate ('squeal'). The second might be caused by stray RF getting into the mic itself when keyed. Using a disc capacitor across the mic terminals (don't remember the right value ATM) can trap the RF. I would just check the mic wiring for starters; and then go from there . . . [/QUOTE]

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