ATR Throttle won’t set or hold

[arrowspace90 4]

I have a new Bravo so I can fly the ATR.  I set it up using tutorial from SimHangar.

For a couple of weeks it worked fine on the ATR.  I also use it for PMDG737 and XP12 737, with profiles for each.

Then on ATR, #1 throttle started moving out of Notch position, falling to flight idle.  I would move  Bravo to reset it, but it would quickly fall again.  I yesterday tried deleting all throttle 1 assignments and reassigning them.  That worked for 1 flight.  Now it is either at full reverse position or full throttle.  No in between.  The other throttle works fine.  The 737 doesn’t appear to be affected.

What should I try?  How can I tell the difference between an assignment conflict and a hardware problem?  I lack expertise to fix this.  Can someone suggest a strategy beyond “Check for conflicts”?  
I really like Bravo and I just want it to work.