check for battery voltage on both sides of diode d2 on the cpu board. these fail from time to time
also check if the d2 has gone short, if it has then the circuit will be trying to recharge the batteries

All tested fine including the pins at the Rom chip..

Ive reseated all the connectors and Ics on the Cpu board and it seems to have gone away for now...

Still not sure what the Mod at U10 is for..