Need Help with Cub Cadet 128 Charging

   / Need Help with Cub Cadet 128 Charging #1  

Smalljobs

Gold Member
Joined
Mar 8, 2009
Messages
345
Location
Massachusetts
Tractor
Jinma 284
I really need some help with this problem:

I've owned this 128 for around 30 years and have done nothing to the charging system. A black VR was on the machine when I bought it.

I noticed the two year old battery kept going dead and it found it would not charge. Although I could jump start the machine, it died when the cables were removed. My charger showed an open cell error code so I installed a new battery. While running, the ammeter didn't move except for vibration so I suspected the Starter/Generator (SG) was not charging. I ran a wire from the F and briefly grounded the running SG with no results so I bought a new SG.

Once I got the tractor running again I noticed the charging meter still didn't move so I bought a new gage and new Stens VR.

First I installed the new gage and then started up the tractor. The new gage didn't move at all.

I carefully installed the new VR and connected the three wires and ground in exactly the same location, one by one, without knowing the label on each tab was different. Then I connected the (+) side of the batter first. When I connected the (-) cable, the SG started turning over the engine. There was sparking when I briefly connected the (-) cable. Then I removed the battery and swapped two of the VR wires and tried again. Same result. Finally I discovered the BATT connection on the VR was on a different tab than the old VR. So I moved the BATT wire to the correct tab on the VR and tried again. Finally I think I have it wired correctly.

So far so good with no sparking when I connect the (-). The tractor started right up and but the new charging gage sits at zero around idle and sweeps to the discharge side when I raise the RPMs. I double checked the (-) and (+) connections on the gage and they are same as when all this began.

I don't know if I damaged the VR or the gage when I miss-wired the VR. Now, I'm really stuck and need help.

I cannot put the old VR back in because I opened the cover and found it was full of old rusty water.
 
   / Need Help with Cub Cadet 128 Charging #2  
Steve, if the tractor cranks then the s/g is good! Redo the polarity and it should work. The generator is not as high of an out put as a alternator and if the battery is fully charged it would not show much at all on the gauge.
 
   / Need Help with Cub Cadet 128 Charging
  • Thread Starter
#3  
Art, Thank you. I understand polarity but don't know which wires to reverse? It is the two non-BATT wires on the VR or the two on the charging gage?
 
   / Need Help with Cub Cadet 128 Charging
  • Thread Starter
#4  
I did some research on the reason for and how to change the polarity. Will try that later today.
 
   / Need Help with Cub Cadet 128 Charging
  • Thread Starter
#5  
Found online instruction for polarizing. I connected the battery and removed the F lead from VR and momentarily touched to BATT. Big spark. Then I started it up and the ammeter continues to move left in the discharge zone. I took the new VR apart and found no burning or arc on points. It all looks new inside as it should.

Still need help.
 

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