bridgeport interact 412 problems need help

I have a interact 412 with heidenheim tnc controller ,bosch drives, fanuc spindle.

a few days ago when i turned it on after a lengthy downtime (about 1 month). i had issues with the machine homing in z.

after turning on the power it goes thru the memory test ok. i reset it with the ce button, press the yellow button that turns on the drives.

then press the cycle start button. z moves first if it is highlited in yellow the head will move down. (the highlight will be romoved).
this will happen if all 3 axis are highlited in yellow (i guess this moves them off the limit switch).
I then press the cycle start again. The z axis will move up but it neves seems to home. It goes up till it hits the upper limit and just sits there
doing nothing.
the other axis will not move till z clears (which does not happen)

not sure what might be happening.

I checked the drives and have a green light on all 3.
checked all the parameters (they are ok)

Any ideas???

Thanks
Mike

Was the Z sem motor change recently ? I would try moving the pulley on the Z motor up just a little bit and see if it helps.