[Elecraft] Applied 12V to accessorie jack

[Don Wilhelm]

Paul,

Hopefully, that individual did not connect to the APP connector with 
reverse polarity.
The KPA100 has no reverse polarity protection because of the current 
requirment would require a very large diode, and the voltage drop 
through the diode would be a problem.  Protection for the KPA100 relies 
on the 20 Amp fuse in the power cable (which was not used).

If reverse polarity was applied, you will find that the bottom of the 
KPA100 board will have many traces that have become "history". The only 
solution for that is to remove components from your existing KPA100 
board and putting them on a new board - or just constructing a new KPA100.

Hopefully, that is the worst case, and your problem is something more minor.
I suggest physically removing the KPA100 and test to see if the base K2 
is functional (the base K2 does have reverse polarity protection).

If the base K2 is OK, then the problem is in the KPA100.  Remove the 
KPA100 board from the heatsink and look for burned traces - that is a 
sure result of reverse polarity (with no fuse in place).

If the KPA100 board looks intact, ask again with those details and we 
can help you troubleshoot the problem.

73,
Don W3FPR

On 3/11/2014 3:10 PM, paul hendershott wrote:
> Hi Folks,
>
> I lent my K2100 out to a ham in Reading, PA a few years ago
>
> and apparently he misplaced the power connector and applied 12V directly to
>
> the 12 V power-out jack (Anderson Power Pole connector). He said the radio powered up fine, but when he went to
>
> tune up and transmit, the unit went dead. I got the radio back about a year and a half ago
> and want to dive in and see what might have happened. Can anyone give me a place to start
> or have an idea if I'm looking at just replacing a fuse or something more involved?
>
>