I don't think that I can help you out much. The only thing I can tell you is that I have a Hardinge VMC 600 and it runs fine on my phase converter. The only thing you might check is to make sure you haven't lost the parameters and that the D cell batteries have been replaced. They should be right inside the panel. Read the manual.
You can also contact Hardinge (607) 734-2281 they are very helpful, even if you purchased the machine from another party. Make sure you have the serial number, it is located on the electrical panel door.
If it has a Fanuc OM-D control you may want to check with some of the guys on the Fanuc forum. There are a couple of real sharp guys there that could probably help you out.