[Elecraft] Re: K2 S/N 1325 KSB2 module problems

[Robert C. Abell]

I have been upgrading the captioned K2 for a friend.
I installed new matched xtals in the entire rig as well as the KSB2 module.
I replaced U6 the MCU on the Control board and U1  the IOC on the RF Board.
I did not upgrade U1, the IC Microcontroller on the KSB2 Board.
The KSB2 now is not working properly on transmit, I can just barely hear 
the transmitted signal on my monitor receiver and there is no segment 
lit up on the bar graph.
The received signals are normal.
Is it necessary to upgrade U1, the Microcontroller on the KSB2 Board too?
This is not clear to me. Any help would be much appreciated.

73, Bob  VE3XM
K2/100  S/N 4031
K2  S/N 4575