PRECHARGE FAIL ERROR CODE in an OEC 9600.

Either the batteries are bad or 12vdc supply is missing in Generator driver PCB.
aparnaelectromech@gmail.com

It means the system has not completed the precharge cycle, sensed by Analog Interface PCB from +200V (B+) on Generator Driver PCB.

The PRECHARGE signal passes through the Motherboard and X-ray Regulator PCB, energizing Relay K1 located in the Generator Controller Assembly. This allows charging of the pre-charge capacitors C2 & C3 from the batteries/battery charger through relay K1 contacts 6 & 9 and resistor R1. Resistor R1 limits the initial in-rush current to the
capacitors.

The voltage across the pre-charge capacitors C2 & C3 is applied through fuse F3 on the Generator Driver PCB to the voltage divider R10/R11. This voltage divider scales the precharge capacitor voltage to approximately 2.5% of the original value. This scaled voltage becomes the +200VSNS signal. The +200VSNS signal is monitored by the Technique
Processor PCB through A/D Mux U3-8 on the Analog Interface PCB.

If the Technique processor never sees the +200VSNS signal reach approximately 4.5 VDC during the boot sequence, a pre-charge error is detected.

The message PRE-CHARGE FAIL will be displayed on the Control Panel display if the Technique Processor PCB does not see the +200VSNS signal reach approximately 4.5VDC during the boot sequence (Approximately 185 VDC across pre-charge capacitors).
This is a fatal error that prevents the system boot from completing.

Hello. Most likely the problem is with the batteries. If the batteries are OK, check the charging voltage - the procedure is described in the service manual.