It is the wrong manual but the way I am reading it is. The probe is connected to pin 1 on the 9 pin control plug which goes to pin 15 on the D25 plug to the PP. Have you checked the continuity on the cable pin 15 to pin 15 each end of the cable going from the machine control box to the PP on the computer. Or from pin 1 on the control plug through to pin 15 at the pc end of the cable PP. Some more pictures might help. ..Clive