[Elecraft] KRX3 calibration failure

[ON4WIX]

Hello,

yesterday I installed the KRX3 into my K3 s/n 0192.
All went well and after the installation the main rx and the tx seem to work 
fine.
However, I just tried calibrating my KRX3's synthesizer.
Initially this goes as expected but suddenly the values on the VFO display 
add up very quickly and then I get "E00039" on the VFOA display and VFOB 
shows "ERR VC4".

Please advise on which steps to take to remove this error.

Thanks in advance

Glenn ON4WIX