[Elecraft] K3 Not Turning Off

[W1UE]

My K3 will no longer turn off.  The LEDs on the front panel won't go 
off, and all the
lettering on the Liquid Crystal Display will disappear but the LCD will 
still be backlit.

I've traced it down to the 15pin accessory plug; all I have attached to 
it is a 1 transistor
keying circuit to key FSK on Pin 1.  If that plug is attached, the K3 
won't shut off.  If that
plug is not attached, the K3 shuts down normally.

Will the 12V sense mod allow me to leave the 15pin plug in and still 
shut down K3 properly?
Or should I try a different circuit to key FSK?

Dennis W1UE