Polar 115 Emc stop problem

Our polar Emc II(without monitor)
Have a problem with stop and it sometimes give measure lower than setting measure and sometimes give measure higher than setting measure
I thing its stopping error?
I gives ------- then 42.028then ------
I changed IAR and IHR from another machine

 

You can try changing back gauge braking distance. To do this turn machine of while back gauge moving. Then when you switch back on you have to run back gauge to recalibrate, this also resets braking time. If this does not help strip and clean back gauge motor brake. Good luck.
Andy