5M Spindle drive problem TGAL Alarm

Hi from Germany
We are a small metall manufacturer and drive some Fanuc´s and Gildemeisters
Right now we have a Problem with a 5M on a Hitachi Seiki MN500 center.

When powering up the TGAL LED gets on and we cannot drive the spindle. It doesn´t get to alarm so the problem seems to be on the spindle drive side...
We did all checking as far as the manual gets us the information. But still we have the same situation. It seems that the three phases get onto the platines but we cannot check further cause we don´t have any further repair manual for the A20B-0005-0584 and the A20B-0005-0611 only the manual.

The manual says the TGAl alarm lights when there is wrong phase rotation or when one phase lacks - as we didn´t change anything on the phases here there seems to be a problem with a phase.

Just a feeling an this just because we had some issues with these- can there be a problem with those Fanuc/Siemens Hybrid IC´s???
there are three of them
http://i.ebayimg.com/t/FANUC-HYBRID-...VjDpU/$_57.JPG

as well as three A-OS02

As I smentioned bevore - it´s just a feeling! But we had some issues with those on an other axis drive

Can anybody help me with better info about repair of the spindle drive?

Best regards and many thanks in advance

Andreas