Kubota L3130 - Alternator not Charging - 7.5 Amp fuse circuit has short to ground

dochsml

Member

Equipment
L4701HST
Jan 21, 2020
216
20
18
Leonard, TX, USA
The sad finally -- So here is the conclusion to this problem as I see it.

First to clear up a few comments made above,
1) The battery was connected at all times,
2) discussing this problem with the shop that fixed the alternator, we believe that one half of the Diode Bridge failed and that created a voltage spike that fed back to the panel and fried it.
3) I do believe it is a poorly designed IntelliPanel, if not from the standpoint of being fault-tolerant and being able to tolerate the diode problem, then from the standpoint of having so much function in one component of an electrical system that failure of that component cost $850. Which is what I just paid for a new panel !!!

Here are some additional details of the problem, from the schematic I have which is out of the Kubota “WORKSHOP MANUAL TRACTOR L3130,L3430,L3830, L4630,L5030 ([3] HST MODEL) page 468” dated November 2003.
The 7.5 amp Alternator circuit (and the IG signal from the Alternator) connects the IntelliPanel to Pin 9 of the “B” connector show on this schematic. In my case checking continuity Pins 9, 1, 2, 3 are also connected and I believe this occurred when the voltage spike occurred, Pin 2 is a ground which causes the Alternator fuse to continue to blow when the IntelliPanel is installed and the key is turned on. (one note this pin numbering is form the schematic the circuit board numbering is different)

I thought about hacking up the circuit board to bypass this failure, but then I figured I would end up with a $15,000 tractor with a screwed up and unreliable display panel, so I did what an older gentleman once told me “Sometimes you have to belly up to the bar and eat the Reality Sandwich” meaning, in this case, go to the dealer and pay the money for a new panel, which I did.

The new panel should be here in a couple of days, I will post when I get it all back together and confirm that it works. I posted pictures of the circuit board and indicated the problems in the blue marker. (well I tried uploading the picture and the system gave me an error, I will try again later today)

I hope this helps someone in the future.
I agree with your assessment that there should have been some kind of protection on something as delicate as a circuit board. It is even possible that there was / is protection designed into it, but it could have failed.