[Elecraft] K2 display problem

[Hein de Boer]

5 and 6 are the only digits with segment b off
2 is the only digit with segment c off
segment b and segment c are on the same run (with dp)

Now the problem:
If the seventh (last) digit on the display is a 5 or a 6 , so b off, everything is OK
With everything else (so b on ) as last digit the segments a,b,f become significantly less bright (all over the disiplay)
With 2 as last digit only the segments d stay bright.

Who can and will shed light upon this problem? Many thanks in anticipation.