Hi I have a duplex 21 ucl control, one car is fine, the problem car-parks at 2nd landing and only answers a down hall call. Once you're in the car it goes anywhere you want, top to bottom non stop, but without any car call it will stop at every landing in the down direction normally cycling the doors until it reaches its parking floor. Pie plate selector, no pcb on top. Cleaned all floor bar contacts but can't seem to make the problem stop. Prints not great. I need help been in the industry more than 25 years never saw this before. Anybody have any ideas?