On Sunday, February 16, 2014 6:33:37 PM UTC-5, Mick Nowell wrote:
Disconnect the PU from the door. Get a scale and see how much force it

takes to open each unit.

Before any modification I suggest exercising them. Pop each one open

and "brillo" the oxidization/whatever on each surface. Repeat.

+1

All the speculation is based on the conclusion that residual magnetism is the problem, and that may be premature.

Turn the power off, take an ordinary piece of steel like a cover plate, and see if it sticks to the magnet. If it does (which I doubt) put a multimeter on it and confirm the power is really off. Then use the spring scale to see how hard the steel sticks.

Compare that to how hard it is to pull the door open.