Brother "home position" help

I recently bought a brother bas 415. The problem I am having is that my machine doesn't appear to be going to a dead centre home position. On the y axis I am off by about 3/4 - 1 inch. I have gone though the manual and service manual but nothin seems to help. What am I doing wrong. Essentially Anything I do won't be centered.

Any help is much appreciated.

Thanks in Advance

Kris