I had a problem with my Bk2000, as the pin warmed up all the solenoids and flippers seemed to get weaker, I cleaned all plungers and replaced all sleaves and no change.
I then put a fan behind the pin so it blew air into the vents, they seemed a bit stronger but not as strong when the pin was first turned on.
Next step was to replace all the capacitors and bridge rectifiers on the aux driver board, after i refitted the board into the pin not only do the solenoids and flippers stay strong they are stronger than what they where before the repairs.
I checked all the old components with a multimeter and they checked out fine. so i heated the bridges up with a hair drier and found both bridges increased there forward voltage drop across one of the internal diodes
problem solved.