hello, new member need's your help

Hello I am new with this instrument and I need your help, I am musician and electronic engineer, my friend has a theremin and It burn his power suply, after to repair his theremin no longer works well, when he moves the hand that works the pitch the tone does not change, i want to help him with this problem, thank you very much

Hi.

If the power supply was damaged by a voltage surge, it could be possible that other components were weakened or damaged.

Would be helpful to know what kind of Theremin it is.

Since you are an EE, would suggest that you check out the forums under "Theremin construction" and checkout the schematics section, too.

Good luck!