Hey hef got a good head scratcher first off it's a sk330-6lc had very dead batteries tried charging for sort time then tried to crank rolled once or twice and I quit told customer put new batteries in it. They did hooked them up correctly tried to start cranks no start said it had blown fuses and called be down. Fuse 13 that will keep blowing in for the dash cluster ohms on power wire to cluster 2 ohms = shorted. I pulled cluster apart and one restitor it shorted to capacitor could smell I mile away. So now I diagnose fuse 3 ecm engine controller 3 ohms on power wire from fuse to ecm. Call around ecm is $8000 and can't find anyone near Pennsylvanian to program it so for ***** I pop it apart and it looks like brand new inside no discoloration smell anything. I have a schematic on cd but having trouble following it. The power wire to ecm is great ohms fine no bad spots but when hooked to ecm I get 3 ohms to chassis so I'm wondering if one of the other wires in plug could be shorted It sure isn't a cat diagram lol if anyone has any ideas even of someone in pa that has some electrical experience on kobelco to take over I'm all ears
After some more hair pulling with batteries unhooked if I unplug all but the top connector a five pin 2 power 2 ground and a ecm reset I have 3 ohms to chassis at fuse panel on power wires going to engine ecm. If I unhook the powers and grounds connector for engine ecm. The harness ohms out good no shorts to ground. So it seems ecm is shorted but if I look at circuit board looks in good shape and don't smell burnt. Also found machine ecm will pop it's 20a fuse. And it ohms out like it's shorted to ground. So as far as i can tell it's got 2 bad ecms and a bad cluster.
And thats bad luck lol
Anyone ever seen a machine with all major ecm/controllers shorted out ? And what was cause batteries / connections welding lightning ? I can't find a cause for them to be bad. How could I justify plugging new ones in......
Have saw that before and one of the biggest causes is people jumping the battiers or welding on the machine with out unhooking them.
That sounds to me like a classic case of someone hooking up the batteries around the wrong way. Its all over in milliseconds just a bump of the terminal. I assume the fuses where not blow when you first tested so something after that has caused problems. Your ohm meter is only ok for cursory checks for shorts in wiring with resistor or inductive loads. Totally useless in diagnosing a short in electronic boards as the active components will change the resistance as they are powered up. They appear to have low ohms but spike quickly up to higher resistance when energized. Im not saying you don't have bad boards but you carn't test them with ohm meter. The best way would be to use a external power supply with voltage and current control. Typically if you suspected a short you would dial up a low current which is limited so the inrush would not damage the components. You can buy one for less than 100dollars at an electronic store and would be cheap investment before purchasing $8000 dollar ecms. Regards.