DEK 265LT Rising Table Position Error

I'm hoping that someone may be able to shed some light on this error we've been getting on our DEK 265LT printer. Several months ago we began getting a "Rising table position error" after the operator would open the hood to load paste or after changing a screen. The machine would have to be rebooted and usually the problem would resolve itself. Sometimes, however, it would not and would require several reboots. We replaced the rising table brake as we could see the table would actually drop about 10 mm and thought the brake was malfunctioning. It continued after changing the brake. We believe now it is not the brake because the brake engages correctly when a soft estop is activated such as lifting the head (besides the fact that we replaced the brake a second time, just to be sure). It is only when a hard estop is activated that it appears the brake engages just a touch too slowly and the table drops a bit. DEK tech support came out and discarded the possibility that it was a worn rising table ball screw as the brake would engage for a soft estop at all the locations it would fail to engage on with the hard estop. The technician spent the entire day changing out cards, servo drivers, relays and connectors inside that machine itself and also with a second identical DEK on a different line without being able to find what was causing the delay in engaging the brake. He ended up modifying the sensor flag so that it would not drop into the limit sensor and error out and we were able to run for two days. This morning the machine had errored out again with that same error and the table will not move from where it is near to the home position but not actually at it. Any ideas, thoughts or suggestions would be greatly appreciated (well, other than to buy a new machine :) )

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