I just went through the same issue with my 725. First checked alternator voltage. Don't know what the specs say, but mine was in the neighborhood of 30-50VAC depending on RPM, so I called it good. Next, I checked external regulator and wasn't getting anything out of it. So I ordered a new one. However, when the new regulator came and I actually disconnected the old regulator, I noticed one of the spade terminals had come partially out of the plug (on tractor side). After testing the new regulator and verifying the system was charging correctly, I switched back to the original regulator which turned out was also working correctly.
So I've got an extra regulator now if anyone's interested. Replaces Grasshopper 185530, Kubota RP201-53710, 6 contact plug. $48 - PM if interested.
The voltage on my 725 still occasionally goes low. There's a little corrosion starting on my fuses, and by moving the fuse my voltage varies. So next I need to clean the fuse contacts and grounding points while I'm at it.
So I've got an extra regulator now if anyone's interested. Replaces Grasshopper 185530, Kubota RP201-53710, 6 contact plug. $48 - PM if interested.
The voltage on my 725 still occasionally goes low. There's a little corrosion starting on my fuses, and by moving the fuse my voltage varies. So next I need to clean the fuse contacts and grounding points while I'm at it.