140 Generator

RTR · Mar 19, 2012

Hey guys....I've got a late 1973 Farmall 140 tractor with the original 12 volt generator. It isn't charging, and since I've broken my leg I can go out and tend to it. I am going to get my uncle to diagnose and repair it for me. I know I've asked this stuff before and I have the procedures printed out to follow, however at my current state I can't get to them to give to my uncle.

I was hoping someone on here (JohnT I believe helped me last time), could give me a fool proof diagnostic troubleshooting method for the 12 volt generator charging system. I know alot of folks chime in with thier methods and while most of them are similar, I would like to have a good standard one to use, and hopefully make my own repair/troubleshooting manual from it to use in the future so I don't have to ask you guys for help.

With that being said, I appreciate everyone on here and what you all do for us tractor enthusiasts!! I look forward to recieving a guideline to follow for this charging system. I will basically call my uncle and read off the steps to him, and maybe we can get this thing tackled!!

John T · Mar 19, 2012

I wouldnt call this foolproof and its far from perfect, but if you work through it, especially Para 5 where it shows how to full field the genny which by passes any Voltage Regulator or Cutout Relay problems, it ought to tell you if the genny is bad versus the VR etc. The Motor test also shows how to determine with a good probability whether the genny itself is good or not, as if it passes BOTH tests it will usualy charge.

As always, the Genny and the VR or Cutout Relay and the light switch (LHBD switches) allllllll require good grounds and its good to Polarize the genny if in doubt before start up if the system has been worked on.

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=farmall&th=665110

John T
John Ts Troubleshooting

RTR · Mar 19, 2012

Thanks much John!

RTR · Mar 23, 2012

John,

Another question......got the 140 troubleshooted and found a bad regulator. Thank you for the guidance.

I've got an IH 424 Deisel tractor with the same charging system (12 volt generator with regulator), BUT it does not have an ammeter. It only has a "dummy light". I noticed that the light remains on after cranking the tractor and stays on until you rev the engine and let the tractor run for a little while (about 2 minutes at half throttle). Once you let the engine back at idle, the light comes back on. I have reason to believe that the charging system is faulty somewhere. All of the wiring is original, untampered, and looks really good. I don't believe that is the issue. So tell me.....how in the world would I troubleshoot this charging system since it does not have an ammeter to let me know if it is charging??? Looking at the light is like a baby crying.....it can't tell you what's going on. Am I going to have to get out a multimeter, or is there another way to troubleshoot?? IF I have to use the multimeter, please instruct on where and what settings to use.

THANKS!

(quoted from post at 22:18:09 03/19/12) I wouldnt call this foolproof and its far from perfect, but if you work through it, especially Para 5 where it shows how to full field the genny which by passes any Voltage Regulator or Cutout Relay problems, it ought to tell you if the genny is bad versus the VR etc. The Motor test also shows how to determine with a good probability whether the genny itself is good or not, as if it passes BOTH tests it will usualy charge.

As always, the Genny and the VR or Cutout Relay and the light switch (LHBD switches) allllllll require good grounds and its good to Polarize the genny if in doubt before start up if the system has been worked on.

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=farmall&th=665110

John T
John Ts Troubleshooting

140 Generator

RTR

Well-known Member

John T

Well-known Member

RTR

Well-known Member

RTR

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