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John Deere 420S generator question

4

420Mark

New User
My 420 had the generator and starter professionally rebuilt a few years ago and they both worked as advertised. The past few summers the generator fails to charge. The amp meter shows no positive movement. I have cleaned the contacts on the generator and regulator. That said, it still won't charge. I polarize the generator and it charges fine. The ammeter shows positive movement and life is good.

The next day I start the tractor and no charging again. I polarize the generator and it charges again. Has anybody seen this condition before, or have any ideas where to go troubleshooting this issue?

Thanks,

Mark
 

cvphoto102074.jpg

This simple to follow chart should help you.
 
Heres my Troubleshooting Procedure regarding charging problems. Make sure BOTH the Voltage Regulator and Genny have good grounds !! In the
event a shop polarized the genny at the typical NEG ground and you started the tractor at the wrong polarity (JD was POS) you may have
damaged the Voltage Regulator


https://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=ttalk&th=2060825

John T
John Ts Charging Troubleshooting
 
(quoted from post at 15:33:13 09/23/21)
<img src=https://www.yesterdaystractors.com/cvphotos/cvphoto102077.jpg>
Click to expand...

Thanks for the quick replies. I'll check out those tips.

Regards,

Mark
 
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