Hi2all
The problem occurrence while phone can't read battery ID resistor...
Possible cause is a:
bad battery ID resistor (change batt!);
bad wireing between batt connector and ASIC chip - for 9xx chip is SAGEM 18599662-5 ( check wires and resolder all connected components);
bad ASIC chip ( change/resolder ASIC);
Bad PCB - destroyed or some deformation(no solution!);