Arrow 1000 spindle trouble

[raygun]

the arrow 1000 mill I'm working on has got me baffled. When it goes to change from tool 4 to tool 5 the z axis moves up from the part but not up to tool change position and then sets there with the spindle running. It will have no alarm and will sit there running for infinity. I cleaned and reseated all the connectors to the spindle amp and the problem went away for 2 days, then reoccured.
Help
Ray

[LeftCoastCNC]

Is it just when it changes from tool 4 to 5 or any tool change? If you shut off the spindle with an M9 before the M6 will it change tools? Does it only have this problem in one program or any program?

[raygun]

Only from tool 4 to 5. This is the only program it has been running. The program looks good. you can stop the spindle and do a tool change. Then it may run 1-50 parts before the problem reappears.

[LeftCoastCNC]

Are you running sub programs with an endless loop? I have had strange things happen when running loops. It has always been programming problems that were not easy to find.

I really have no other ideas, that is really strange.