70D CHARGING PROBLEMS

GENERATOR AND VOLTAGE REGULATOR TROUBLESHOOTING:

Below is my standard test I have posted often before to tell if its a Generator or Voltage Regulator problem if shes not charging. However, you still have to have a good battery capable of taking a charge and all the wirign and grounds must be good and in place first.

1) First, be sure the belt is good and tight and the generator has a good ground to the tractors frame and that the VR has a good ground to the generator. Many problems are caused by a bad ground to the generator or the VR is not well grounded (usually to the gens case). You might run a wire direct from the batterys grounded terminal down to the gen and VR and and connect it to see if thats the problem.

2) There has to be hot full battery voltage present on the VR's BAT terminal so its output can get to and charge the battery. (Use a test lamp or voltmeter to insure that before you go on) The HOT path to get there, is from the battery itself or off the starter post, to and through any ammeter, then down to BAT on the VR.

3) Now if the grounds are good and the VR's BAT terminal is hot, you can finally test the gen and VR to determine which or both are bad. With the tractor running, use a jumper wire and connect the F post out of the generator (smaller of the 2 gen posts) to the generators steel frame ground, and if the ammeter then shows charge, you either have a bad VR or a bad/broken wire connection between the generators F post and the F terminal on the VR.

4) If she still doesnt show charge, leave the F grounded, and then momentarily connect the BAT and ARM (or GEN) on the VR together to see if it shows charge. If she charges then, you have a bad cutout relay inside the VR. If it shows charge only if you connect the VR's BAT terminal direct down to the gens ARM post, the wire is bad (open) between the gens ARM post and the VR's ARM terminal.

5) With the F still grounded and the GEN or ARM on the VR connected to the BAT terminal and if the Gen and VR have good grounds and assuming the BAT terminal is connected to the battery via the ammeter and she still dont charge, its probably a bad generator, cuz you have essentially by passed any bad VR with the tests above.

6) You can also motor test the gen by removing its belt and all its wiring (protect all the wiring so it doesnt short out) and jump wiring the ungrounded bat terminal (i.e. - on a + ground system) to the generators ARM post (larger of 2) and the generator should turn like a motor. A source of such battery power could be the wire from the VR's BAT terminal, as it leads to the battery via the ammeter. If it runs when you do that, then ground out the generators F post and she should slow down slightly. If not, the gens field may be bad. If the gen turns when you apply battery voltage (from the BAT lead or elsewhere) and slows slightly if you ground out the F post, it should generate power fine.

7) For the generator to charge the battery, there has to be a connection between the BAT terminal on the VR to the battery (usually via the ammeter) and test that by using a test light or DC voltmeter and battery voltage should be present on that post ALL THE TIME. If the gens power doesnt reach the battery, it cant ever charge it, and the path is out the ARM post on the Gen, to the GEN or ARM terminal on the VR, through the VR's cut out relay, out to the BAT terminal on the VR, through the ammeter, then to the battery.

8) If she dont charge despite all that and the tests show the gen is bad and NOT the VR because you by passed BOTH the Field and Cutout Relay per the tests above, and the rest of the wiring is good and the gen and VR are grounded properly, heres a few gen troubleshooting tips:

a) Many problems are the brush hold down spring assemblys are rusted and corroded so the brushes are not held down tight against the commutator. Use a wire brush and WD 40 and air etc to clean and free up the hold down spring assemblys so the brushes are held tightly down. If the brushes are not worn down too low and held down tight and she still wont charge, you may have an open field winding or a bad armature or a commutator problem. Post back if you want to repair the generator and maybe I can provide more tips.

9) I assume you have tried to polarize the generator lately??? With the tractor off but all the gen and battery and VR all wired and connected properly, momentarily flash jump a wire from the VR's BAT terminal over to its ARM (or GEN) terminal and you should get a small spark.

Im plannign a full one or 2 articles in upcoming Green Magazine issues in maybe July August time frame to cover this topic, but this should get you going hopefully. Post back any questions.

Good luck n God Bless the USA

Ol John T Nordhoff in Indiana.

~Lets get the charging system operational then worry about the fuel gage.

~Start at the voltage regulator,,, you MUST have battery power at the [BAT] terminal on the voltage regulator for it to charge [if you don�t, find out why] - the VR [BAT] terminal gets it�s power from the NON battery side of the ammeter,,, next, make sure the [FLD] terminal on the VR is hooked to the [F] post {smaller of the two} on the generator,,, next, make sure the [GEN] terminal on the VR is hooked to the [A] post {larger of the two] on the generator,,, next make sure the fuel gage trigger wire is hooked to the [GEN] terminal of the regulator [I have seen a lot of those fuel gage wires hooked to the [F] terminal & that is incorrect, there must be faulty wire diagram floating around out there somewhere]

~If all is wired per above you then need to polarize the generator.. to do that just momentarily hook battery power from the [BAT] terminal of the VR to the [A] post of the generator, you should see a spark & that means it�s polarized]

~If all above is correct & done re-try it to see if it now charges. If it still doesn�t charge make sure the belt is tight & both the generator & regulator have a good CLEAN ground, both to the engine & to each other�

~To check the charging system �run the engine at fast idle & ground the [F] post on the generator to the generator frame [if it then charges you either have a bad regulator or open in the wire between the generator [F] post & regulator [FLD] terminal]�If it still doesn�t charge, leave the [F] post grounded & use a jumper wire to hook the [A] post on the generator to the [BAT] terminal on the regulator [if it charges now you either have a bad regulator, or open in the wire between the generator [A] post & regulator [GEN] terminal.

~If it still doesn�t charge, re-check for battery power at the regulator [BAT] terminal..

~Your generator was tested twice so there is no reason for me to give you a generator testing sequence [post back if you find a need to test the generator]�.

Try some of the above & see what you have ... If you want to test the fuel gage circuit just hook the gage wire that runs to the regulator to the regulator�s [BAT] terminal if it�s working & the gage circuit is functional it should allow the gage to read the amount of fuel in the tank�

~It helps to print this post out & take it out to the tractor with you�.