Well, I have it back working!
Although, in the process the first floor call station display digit no longer lights. Not sure how that happened, maybe I did something or it was just a coincidence (I hope), but I can fix that later. I have emails out to access2parts and world-electronics to see about a spare and/or repair of the call station.
In the end there were many problems and I think there has probably been little to no maintenance performed over the years. The initial E8, BP Error was the actual problem that took the unit down. In the end, the magnet sensor for the first floor magnet went bad on the magnet sensor circuit board. I probed each magnet sensor with my multi-meter and ran the correct polarity magnet over each of them and BP1 did not react while BP2 and BP4 did. These sensors are hall sensors and similar to what's used on cars for wheel sensors and crankshaft and camshaft position sensors. In my experience on cars they do die occasionally. There are three magnet sensors on the circuit board and my house only has two floors, so I de-soldered the BP4 sensor since it is not used for for only two floors and put in in the place of BP1. They are surface mount components, but not the smallest, so doable without exotic soldering equipment. That was the fix that got it working. As to if something killed it or it was just a coincidence, I don't know, the magnet sensor board holder was loose and hitting the magnet sensor board.
Along the way, I found a dozen loose bolts here and there, a couple completely unscrewed, although none that would have caused a catastrophe. The first floor final limit switch cam plate was so loose it fell off the rail. The magnet sensor board was loose and hitting the magnet plate. There was magnet "dust" on both the first and second floor plates, although a lot on the first floor plate. I found a couple loose wires, although there could be more.
I made a pendant using the schematic so I could move the cab up and down easily. That is really a must have, especially given where the equipment controller is located.
Thanks for this forum and to everyone who had tidbits in the past and helped me now.
