E3Pro auto home malfunctioning

[Martin_au]

endstops were tested. gantry stops at endstop and then moves back up.

Where was that written?

If the endstops stop working the motors keep moving the part. That did not happen.It clearly registered the endstop.

That is not correct. There are two modes. If an endstop fails to trigger, then the motors keep moving along that axis. If an endstop is permanently triggered on, then you get the weird behaviour when an axis, 1) moves back to release the endstop, 2) stops and begins the sensing routine, and 3) moves back again as it detected the endstop again immediately., which is what the OP reported. Very common behaviour when a firmware has the sensor pin's high/low configuration incorrect for an endstop.

I realise you only google stuff martin, but I tend to go more on 8 years experience with 6 different 3d printers - actual real world experience.

Six whole printers. Wow!

And as a rule when endstops stop working, they just stop working. 90% of the time it's the wiring, the actual switches are such simple and robust mechanisms that they tend not to die.Everything here indicates that the endstop is fully functional.Seems pretty clear.

Agreed. Most of the time, when an end stop stops working, then it's a broken wire and the endstop won't trigger. However, the OP's symptoms don't suggest that is the problem. In this case, an endstop jammed "on" does explain the symptoms. It could also be a glitch in the firmware. M119 is a good spot to start........well, once we fix the blue screen problem of the new board.