[Elecraft] Power output

[Earl]

I have K2/100 ser. 5621 which has bee working perfectly but suddenly began giving a "hi cur" msg.  
The output on the Bird 43 shows 15 when set to 7 and 75 to 150 when set anywhere between 50 and 
100watts on all bands.  I have measured voltages on the KPA100 and so far found that U1-21 and, 
of course, U2-6 read 5v rather than 0v.  Also U2-13 measures .7 rather than 13.8v
Diodes D12 and D14, cathode end gives a voltage which is 25 - 30 volts lower than the chart both on 
Tx and Rx while the cathode with setting over 10 watts, simply flashes up a 1 which I take as being unreadable on my digital meter.
 
Does anyone have an idea where I should look from here?

VE3V!