Got a Farmall 75A that is about 10 years old and 1300 hours. Was using it to rake hay a couple months ago and the tachometer quit working and the battery light came on. I cleaned the posts on the battery and nothing changed. So I put a new battery in since it was still the original and 10 years old. Still no tach and the battery light was on. So I bought a new alternator. Its an Iskra/Mahle 65A and here is link to the one:
Iskra/MAHLE® - Alternator, New, Case IH, 504334055, New Holland, 504334055
The old alternator seems to spin fine. I had probably put 20 hours on the tractor with no tach and battery light on. I assumed that the old alternator had to be charging the battery but the speed sensor or whatever that sends the signal to the tach was bad. So I put the new alternator in and the tach works and battery light goes out so I think I am good to go. After about 5 hours on the new alternator the battery light comes back on and tach quits working again
Until yesterday I was thinking I had a dash problem. Always assumed the alternator had to be working if the tractor would run and start fine. But doing some checking yesterday the battery was down to 11.6 volts. When I put it on the charger it takes a lot of amps so is really pulled down. When I start the tractor the volts don't go up so the alternator is not charging. The volts on the big post on the back of the alternator match the battery voltage <12V and not 14. There are 2 small wires with 1/4" spade terminals on the back of the alternator. They both read about 1.7V and I thought I hooked them up correctly. Should I try reversing them? The harness that runs to the alternator gets grounded to the frame and I tried cleaning up that connection also with no change.
This tractor is electrically very simple. Only a handful of small fuses for dash, lights, horn, etc. Any suggestions on what to try? I still think the old alternator and new alternator are probably fine. Must be something in the wiring somewhere. Any thoughts? Thanks.
Iskra/MAHLE® - Alternator, New, Case IH, 504334055, New Holland, 504334055
The old alternator seems to spin fine. I had probably put 20 hours on the tractor with no tach and battery light on. I assumed that the old alternator had to be charging the battery but the speed sensor or whatever that sends the signal to the tach was bad. So I put the new alternator in and the tach works and battery light goes out so I think I am good to go. After about 5 hours on the new alternator the battery light comes back on and tach quits working again
Until yesterday I was thinking I had a dash problem. Always assumed the alternator had to be working if the tractor would run and start fine. But doing some checking yesterday the battery was down to 11.6 volts. When I put it on the charger it takes a lot of amps so is really pulled down. When I start the tractor the volts don't go up so the alternator is not charging. The volts on the big post on the back of the alternator match the battery voltage <12V and not 14. There are 2 small wires with 1/4" spade terminals on the back of the alternator. They both read about 1.7V and I thought I hooked them up correctly. Should I try reversing them? The harness that runs to the alternator gets grounded to the frame and I tried cleaning up that connection also with no change.
This tractor is electrically very simple. Only a handful of small fuses for dash, lights, horn, etc. Any suggestions on what to try? I still think the old alternator and new alternator are probably fine. Must be something in the wiring somewhere. Any thoughts? Thanks.
