After 6 months of normal use,when I hit ref all home btn.  z hits the prox , dro goes to zero,green light ,all is good. when y goes to prox ,dro will indicate a value of several inches,yet I still get a green light as an acknoleagement that yes I am at home.By the way if I then hit machine coordinates it indicates that very same inch value. If I attemp to zero out that same inch value,Itputs it into G-54 offsets.I cant get rid of it. Z,X,A axis are normal.That same inch value also changes upon each start up.Also that same inch value will show up when all ref bnt. is pushed and Y axis g-54 offsets are shown to be zeroed out.Mach3

Sounds like you have a Home Off value set for the Y, check from Config menu then Homing and Limits.
Hood

Hood,I owe you,I spent 4 days loading and reloading to no avail. Check this out ,the problem occurred when I changed from a 10 foot printer cable to a 25 footer,the machine immediately  acted up.The auto zero default in the homing and limits changed by electrical interference ,yes it can happen.Thanks so much,Ron.