When doing calibration on a saw head one of the things you will need to do is verify the max and min values. The Centerline moves up and down via a motor and chain and is only stopped because the motor mount bracket can’t move any more because it is stopped by the saw frame.
If you get the error "Stall: Centerline 5-v25" during a setup, it can be because blade 5 is hitting the end stop. One possible reason this could be occurring is that the saw is out of calibration and the minimum position (the lowest possible position the centerline can go before hitting the end stop) needs to be recalibrated.
The centerline encoder is the counter that tracks the position of the vertical movement. The centerline encoder is located either on the end of the shaft for the (older) Joyce actuator style or on the end of the shaft of the gearbox (newer style) behind a gray cover.