Really blew it this time...

csimons · Feb 18, 2015

I've had my JD 3520 parked in a garage for some years now - starting it and letting it run to keep the battery up while figuring out what to do with my life. Yesterday the battery was finally low enough to not turn the motor over. I pulled the truck up and hooked up the cables and tried to start it ... and nothing ... until the smoke started coming from the altinator. I yanked the cables off before actual flames erupted, but damage was done for sure. I had crossed the cables.

Any thoughts (besides the obvious ones) about what damage might happened? I assume that because there was smoke that the altinator is history. Since I was trying to start it before (while..) the smoke started, is the starter possible shot as well? When I turn the key now I get nothing.
thanks

Dave M7040 · Feb 18, 2015

Disconnect and tape up the wires from the alternator.
Disconnect and charge the tractor battery.
Connect the tractor battery and see if you have any lights or other indication of power getting beyond the battery.
Starter motors usually don't care about battery polarity. People convert old British tractors with positive ground to a more conventional negative ground and don't have to touch the starter.
I assume you have checked for blown fuses.
Do as suggested and report back and more comments can be provided.
From looking on line your model of tractor seems to have some electronics involved in its operation, The electronics may not have appreciated the reverse battery connect and the dealer may be your best recourse.
Dave M7040

jix · Feb 18, 2015

I did that to a Toyota Camry once. Totalled the car....OOPs!

xring100 · Feb 18, 2015

Its likely that you let the magic smoke out of the diodes in the alternator. Will likely need to rebuild it or replace it.

dkf435 · Feb 18, 2015

My friends JD3520 has the e hydro and if it is like yours there is quite a bit of electronics on it, you will likely have quite a bit of checking to do to see what works and what does not.

David Kb7uns

csimons · Feb 19, 2015

Thanks all for your replies - I'll go at it this weekend and let you know what happens.

What kills me about this is that the battery probably wasn't even dead - when I pulled it out the terminals were a dull grey and a bit funky. Cleaning them up sure made that reversed charge go stronger!

Dead Horse · Feb 20, 2015

xring100 said:
Its likely that you let the magic smoke out of the diodes in the alternator. Will likely need to rebuild it or replace it.

THIS............

k0ua · Feb 20, 2015

Yep, diode trio is done in the alternator, and its on-board regulator is toasted too. Check the main in line fuse, I am not sure where it is on your brand, but a lot of them are in line near the starter. There could be others blown in the fuse box as well.. since you turned the key, you probably energized any electronics modules... not so good...Sorry about that.

dragoneggs · Feb 20, 2015

Yikes... hopefully only the alternator! I would disconnect and charge battery, replace alternator, check fuses, and pray the electronics aren't fried. Good luck.

Herkypilot · Feb 25, 2015

Take the alternator to an auto parts store for testing. Look the wires over from the batt. to the alternator and beyond for melted insulation. You may as well get a new battery since you know that was already bad and go from there.

HP

skyhook · Feb 27, 2015

New alt will be needed for sure, battery may still be good, all depends how "dead" it was. (have it charged and load tested).
Anything in the battery circuit should be protected by a fuse or "fuseable link" .
The alt giving out like it did may have saved some of the other circuits.
Keep us informed, your not the first person to do this.