Electrical Issue on JD 5210

doctorbillmoore · Dec 24, 2018

Thanks for the heads up. I am going to try to figure it out over the next couple of days.

doctorbillmoore · Dec 25, 2018

Well a bit of good and BAD news. I have found the pop was a fuse on the lower left. I had checked the fuses twice before and have no clue how I missed this but I did. Bad news, it is Christmas and I have no 30 am fuses so going to see if I can find a Walmart open close by. Not sure why it is blowing, but need to get the 30 amp fuse it it as specs call for as opposed to the 20 that is there now.

Next thing, am I clear with my reading of the lower left fuse needing to be a 30 a? And any thoughts what might be blowing this particular fuse?

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jaxs · Dec 25, 2018

doctorbillmoore said:
Well a bit of good and BAD news. I have found the pop was a fuse on the lower left. need to get the 30 amp fuse it it as specs call for as opposed to the 20 that is there now.

Next thing, am I clear with my reading of the lower left fuse needing to be a 30 a? And any thoughts what might be blowing this particular fuse?

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ATTACH=CONFIG]584418[/ATTACH]

Glad you found it. Getting correct fuse may take care of it (yes,slot F is 30 amp). If the new 30 amp blow's (immediately or within a few days)post back to this thread so that history is available. There's a simple procedure to nail down ongoing fuse blowing but no need to go there yet. Good luck and Merry Christmas.

beenthere · Dec 25, 2018

Before replacing the fuse (being at risk of it blowing again if a short), then put a 12v light bulb in its place.. if a short, then the bulb will be lit up. If no short, then the bulb will not be lit.

If lit, then you have the capability of tracing the wires to find the short.

For using the light bulb for a fuse, make up some short wires soldered to the old fuse.

doctorbillmoore · Dec 25, 2018

Seems the fuse replacement took care of the issue for now. I can稚 believe how I missed it the first time! Or should I say the first two times. I guess the third time壮 the charm. Now I知 wondering now why the 20 amp fuse had been working just fine for so long and now requires the 30. Oh well, it痴 mechanical.

doctorbillmoore · Dec 25, 2018

That is a great idea! I differ thought of that. Does the light have the capacity of 30 A flowing through it?

the old grind · Dec 26, 2018

doctorbillmoore said:
.. I'm wondering why the 20 amp fuse had been working just fine for so long and now requires the 30. ..

A fuse limits catastrophic damage to wires and allows normal-use current draw. When supply voltage is reduced, devices try to overdraw their rated current. On the coldest day the starter draws & drops voltage the most.

Other loads (sensors, intake air heater, elec lift pump, etc) then can over-draw, and an 'underrated' fuse pops. They may have only pulled 26-8 amps when yours did, but that'd bust a 20a fuse like a Sylvania Blue Dot Press 25.

doctorbillmoore said:
That is a great idea! I never thought of that. Does the light have the capacity of 30 A flowing through it?

The light 'tool' can't really replace a fuse. It will reduce voltage beyond itself and limit current in the fused circuit to roughly its own amperage. By grounding through a load or shorted circuit it will indicate that short circuit or that something is turned on. Full brightness means a 'short', and dimly lit means something isn't switched off. Not much but other light bulbs in the circuit will activate with it in place, and they'll be 'dim' too.

the old grind · Dec 27, 2018

Apologies for applying AC motor dynamics to other devices. (re: counter EMF)

It's not a myth in all instances. While a DC motor can also draw more when heavily loaded or stalled and can suck battery voltage down when cranking, what that does and doesn't do of matter here is in doubt.

What I said about using a light bulb as a fuse may have been less confusing, that it limits voltage and current in its circuit. We ARE talking about a battery whose voltage is reduced when cranking the starter, and more so when oil is cold. If I exaggerated some side effects it's an alternative to seeing the patient in my office and breaking out my VOM to troubleshoot and learn.