[Elecraft] K2/KSB2 problem

[F5UL Bob]

Hello all the team, particularly DON!

Since some week I had a KSB2 problem. The K2 is working perfectly in CW, alone, or with the KPA100,
with the KSB2 position jumpered. If I put KSB2 in place, the K2 Smeter display go to S9 + 40
block the receiver and too, does not switch in Tx when I close either the key or the mike PTT.
I did this morning voltages test on KSB2, and the following list is the values not normal, as 
indicated page23 of KSB2Assembly instruction :

U1-12 = 5.02 (TXC)
U1-14 = 5.21
U1-16 = 0.00
U1-17 = 5.23
U1-21 = 0.00 (RXS)
U1-22 = 4.27 (RXC)
U1-28 = 4.92

U2-5 = 5.36

U3 OK

U4-3 = 5.24

All these values where obtained in Rx. I did not check them in Tx as it was impossible to switch in Tx mode!
All values not noted where per the book!

If I remember well, the U1 is a new one!
Best regards to Elecraft
F5UL Bob