[Kenwood] R-820 Problem

[k1tl@cox.net]

Hi all
Just got an R-820 and works just fine but went to detach the antenna connector from the rear, I got "bit." Turned the radio off and then connected a gnd wire. As soon as I applied power, the circuit breaker to the room blew, along with a snap from the radio. Mysteriously, the radio fuse did not blow...hmmmm!! 
Disconnected the gnd and the radio did power back up and works ok. Has anybody experienced this problem before?
My suspicions are possibly the electrolytic caps in the ps being leaky but have no indication of hum on the audio. Do not want to "experiment" any more since I have been looking for this radio for a long time now and don't want to put it to an "early grave" or myself as a SK!
The plug is a Jones 4-pin and has a two pin AC power cord (the usual Kenwood power cord for that era).
Any help would be appreciated.
  Tom/K1TL