Wow, thanks guys! Great answers...

I adjusted everything as best as I could, got the doors to stay shut. But then they were banging the strike! Did a door learn run, still banging. Increased close slowdown distance, increased final distance, decreased close force at all positions, etc, etc, in other words tried tweaking each and every adjustment available in the close direction that could possibly keep the doors from slamming shut. Tried multiple learn runs, tweaked adjustments ad infinitum. No luck... Never had a DMC do this before, we have always been able to adjust them. In fact on this operator, the open adjustments respond as you would expect, no problem getting the open fine tuned.

It's just like the door operator had no ability to slow the doors down, once they were set in motion, no matter what adjustments were made. I concluded that the door board didn't have the ability electrically to slow the doors in the close direction, once they had been accelerated.

Will try a new board tomorrow, if available.