yes done that - Once - I smoked my 2m ham-gear (TRX).
Smoked Ham tastes and smells a lot better tham burned electronics.
The powersupply got wild and produced more than 13.5 Volts. Unfortunatly the Radio does't work very long on 28Volts. Exploded elko's have a very bad smell.
Since than the psu's have a protection-circuit against overvoltage.