[Elecraft] I need help!

[Roy Vickers]

I need help!
My K2 sn2884 has all the mods and options including the DSP, KAT100 and
KPA100 and was working perfectly. I have been working on a program to
control the K2 via a PDA (I'm a programmer) and I made a big misake, I
plugged the wrong rs232 cable into the K2. After that I got INFO 077 and
nothing else. I unplugged the KPA100 and replaced the MCU 2.03d with an old
2.02H and got rid of the INFO 077. Now I have the following symptoms:
1. depressing the PRE/ATT key causes a momentary KPLY4 to display.
2. depressing the AGC key causes a momentary KPLY5 to display.
3. depressing the SPOT key locks up the radio
4. No audio
5. one bar on bar graph
6. Cal PLL runs OK
7. 5v is OK
Where do I start troubleshooting this problem? Is there any parts that you
recommend replacing right off?
Thanks
Roy Vickers KF5YU