Komatsu FB10RS-12 won't operate, but can be switched on, and gives 'Error 20'

Since 'error 20' is an error on the travel motor, I took out the travel motor's PCB and found out that a few of the mosfets were busted.

I have tried to fix it by replacing a few of the busted FS70UM mosfets, and the unit worked for a few minutes, then something inside 'popped' off again after that.

I checked again, and this time it's a resistor, and still a few of the FS70UM mosfets.

I was thinking of changing the main fuse that leads from the travel motor to the travel motor PCB, to a lower value, so that if something's not right, nothing will 'pops off' in the travel motor PCB, instead will be the 'changed' fuse.

Is it possible and safe?

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Komatsu FB10RS-12 won't operate, but can be switched on, and gives 'Error 20'