You can't replace the diode with a wire, it isn't in series, it is across 
the power line and is supposed to protect against reverse hook up.  If you 
didn't have it fused properly, you could have blown the diode and then 
fried the radio.  I'd bet it is a lost cause.  Remember, the diode is put 
in with cathode to plus and anode to ground.  If you reverse polarity, 
diode conducts, and often shorts or opens.  If it opens and there is still 
power available, fuse has not blown fast enough, scratch one radio!!!\
73s
Butch Bussen
wa0vjr