Couple weeks ago the alternator (idiot) light didn't go off after I started the JD2020. Usually it comes on after turning on the ignition, goes off while starting and then usually stays out while running, normal operation. This is a 3 wire alternator, Field, Positive, and Output. The Field and Positive go to the regulator and of course ground. I forget where but the idiot light is in the circuit too. Pretty sure there will be no charging if the idiot light is out. Well, I thought the $90 Eastern alternator I replaced the original Moto with last August went bad, so I started doing some testing like the Tech Manual says. Didn't get anywhere. Voltage is like 5V on the Positive and a couple volts on the field, this is wrong. The 'full field' test works, so it appears the alternator is working. I bought an aftermarket regulator for $30, prestilite I think. Nothing different. So finally in desperation, I fixed the Moto alternator (bad front bearing) and I know the thing was working when I replaced it. Put it in and still nothing, the alternator light comes on and for sure there's no charging. After I get home this afternoon, I'm going to do a 'full field' test on the Moto alternator and make sure all the wiring is correct. I'm even going to remove those connectors from the regulator and just hook them up without that 4 way connector to make sure all the connections are good. I cleaned the brushes and sanded the slip rings with 360, no diff.
Actually, there were 2 times when it did start working and that happened right after I did a 'full field' test on the alternator and I thought, it was fixed. But no, just a while later it wasn't working. If I can't find anything wrong with the wiring, I guess I should spring for a $110 JD regulator?
Inspecting both the alternators I can't find anything wrong, the diodes appear to be OK, I get good measurements with the diode test with the fluke meter. Of course everything in that alternator is shorted together with the 'wye' stator windings so it's hard to check without breaking down the alternator completely. There are no shorts to ground from the stator or field windings. The field winding appears normal, I can test it on the bench and it seems fine, magnetizes the field coil and gets hard to turn when I put 12V on the field and like I say it passes the 'full field' test, starts charging without the regulator on the tractor.
Any help would be appreciated, I need to start mowing.
Actually, there were 2 times when it did start working and that happened right after I did a 'full field' test on the alternator and I thought, it was fixed. But no, just a while later it wasn't working. If I can't find anything wrong with the wiring, I guess I should spring for a $110 JD regulator?
Inspecting both the alternators I can't find anything wrong, the diodes appear to be OK, I get good measurements with the diode test with the fluke meter. Of course everything in that alternator is shorted together with the 'wye' stator windings so it's hard to check without breaking down the alternator completely. There are no shorts to ground from the stator or field windings. The field winding appears normal, I can test it on the bench and it seems fine, magnetizes the field coil and gets hard to turn when I put 12V on the field and like I say it passes the 'full field' test, starts charging without the regulator on the tractor.
Any help would be appreciated, I need to start mowing.