The charge light on the dash comes on when the switch is turned on, goes off when running. Occasionally the light will come on dimly when running, but intermittently. Can’t figure it out.Does the charge indicator light work? It should come on when the key switch is turned on. There are a few different possibilities with that circuit even if the light does come on. You need to confirm that it gets it's ground through the alternator and not by some other source. Tractors this old often have unusual characteristics associated with wiring, with things being changed/added over time.
Thank you sir. I'll have a look, hopefully enough light when I get home. May be the weekend before I can get to it though. Will let you know.Again, I suggest you confirm the light circuit does indeed reach the alternator. Most tractors of that series with externally regulated alternators used a Motorola system. Typically there are three warning lights in the instrument cluster, plus two dash illumination lights. They all fit the same size holes and can easily be transposed into spaces where they don't belong. For instance, the battery charge light is next to air filter restriction indicator light. The filter light will come on along with the oil light when the key is first turned on, then it usually goes out when the oil light goes out. It can easily be switched with the battery light, giving the indication the charge light came on then went out. I would turn the key on, watch for the charge light to come on, then remove the wire from the regulator terminal on the alternator. The charge light should now be off, and come back on when the wire is again connected. The regulator terminal is a threaded stud on the back of the alternator located at the 9 o'clock position as viewed from the rear. I can't say what color wire it might be, but if you remove the cluster and check the back of the charge light socket, it should match one of those two wires.
That's the simplest test I can think of for that system. If it passes that test and still won't charge, then I'd suggest you investigate the wiring. I have books somewhere describing the various steps to go through with all that should it come to that.