K2 Buttons and VFO not working, No TX or TX.

[DaveVK]

Hi,

I think I blew the radio up after trying to connect a TNC to the mic plug.

Restart radio and ELECRAFT appears.  Then Frequency 14063 in R mode.

Power dial works but nothing else is operating.  No RX, No TX.  No audio from speaker.  Buttons do not work.  Just powers on.  

I wonder if I have blown the MCU?  Or other chip.  Has anyone any suggestions?  Is it worth repairing?

Cheers,