Leadwell VMC-25 ATC - Problem with Tool Change

Leadwell Mill VMC-25 with Meldas M50 Controller

Changed the PROXIMITY SWITCH on the carousel few weeks back - mill been working OK since until today a new problem.

The Carousel lost its way during tool change, capture pot spindle released pot instead of following programme to next TOOL STATION and kept on rotating.
Only way to stop mill was E STOP.

Now the situation is:
Carousel comes across to change pot
Pot unclamps (Panel LIGHT ON)
Then nothing (like waiting for signal)

Ideas?