Romi G-20 lathe spindle issue

[KramerMetalFab]

I have a Romi G-20. The Yaskowa Spindle drive was rebuilt complete last year. The lathe worked fine after that. I use the lathe only for a few runs of parts a year. I just fired it up and now the Spindle will stop like it has no power when my insert is taking only a light cut. The spindle will just slow down and stop. PG-OPEN was the error code on the Parameter unit that plugs into the spindle drive. I have been checking wires from the PG-X2 card and they all seem connected ok.
I have sent the Spindle Encoder to the shop that rebuilt the drive but they are unable to test it. the wires to the Encoder Ohm out fine as far as my testing has gone. Does this sound like a possible encoder problem to you guys ? Do you have suggestions of where I could send this 9 Pin Encoder to test ? Sorry I do not have the Encoder model at this time i did not write down what it was before I sent it off. I will have it back in a couple of days.
Thanks to any one for any help. I am very new to the CNC world so I have little experience with this machine... ** Encoder is Heidenhain brand. ROD 420 series