The plug was indeed wrong, I changed the cables like in your picture (see picture).
Now J605 has the correct voltages, 100v and 80v
But this didn't solve the difference between pin 1 and 2 on J604.
With the connector on (DMD on), measured at DMD:
99,5 (20,7 difference)
Without the connector plugged in, measured at pins on board:
99,4 (20,6 difference)
So I keep having around 20v difference.
And pin 1 is now higher with 120 against 113v yesterday.
Strange thing is that it measured fine in my other pin machines.
Did this board got bad in the meantime maybe or is there something I can check in my CFTBL?