PC490-10 suddenly lost all hydraulic functions... Was tracking the machine and suddenly everything just stopped. When this happened it kinda sounded like a belt blew or something back by the engine, but that doesn't look to be the case. Can a pump just suddenly quit like this?
My money would be on the pump drive coupling.
With Komatsu Dash 10 machines, the screen will display an error when the machine is damaged. Does your machine display any fault code?
I suggest you check the safety lock lever switch, the wiring, fuse No.2, and the safety solenoid valve.
We had a 20,000h plus Hitachi Ex 270 roadbuilder that showed similar symptoms…before complete failure found chunks of rubber from coupler in starter area…