NH Lw170 won't charge?

I have a 1800 hour Lw170 that won't charge the battery's. I think this Is the same machine as a case 621 or 721.

I put new battery's and a alternator on it. Cleaned up the starter, battery and alternator connections. Ran fine for one day. Then today it ran for about an hour and the electronics pulled down and died.

Any ideas or common grounds to clean?

Thanks