who is the komatsu specialist? need help

hello

i'm having difficulty repairing equipment

I need to komatsu specialist help

model is WA500-6. serial no. 55815

first problem appeared error code DAQRKR/2F00MA

so I changed monitor panel (7823 30 7201 -> 7823 30 7103)

error code changed to DAQRMA/DB9RMA

I don't understand komatsu system

what should I do?

any advice is thanks

who is the komatsu specialist? need help