Emco 340 Lathe spindle issue

Machine:

Emcoturn 340 R3C8604006Y
Siemens Sinumerik
Contraves GB 404 main drive
Contraves spindle motor

I have issues!! LOL

I have been working on bringing this lathe back to life. I have repaired many items; Turret, wiring faults, 505 board, and a small list of other things. I have it working to a degree, but still do not have some of the hydraulic options working yet. (I had to pull the NC card to replace a defective fan in the CRT, which dumped the parameters. I have the punch tape, so I feel that can be sorted out after getting a tape reader).


The problem I'm asking for help on is related to the spindle. When I manualy engage (jog mode) the spindle, it sometimes turns at about 66-68 rpms, sometimes 100, sometimes 150 (two times ran away and required shutting main power off to gain control and get it stopped!!)
In MDI, I command, say, S100 M03 and it reports back 200 RPM When I command S100 M04 it continues to spin the same direction and reports back 100 RPM (One runaway here, blowing the main fuse!)
In both Jog and MDI sometimes I'll give a command, and the contactor engages, the load light comes on, but no response from the spindle itself..

When rotating the spindle by hand the tach seems accurate, and registers correctly and reports - #### for reverse; so I think it's feedback is correct. I haven't been able to run it long enough to be able to test for feedback voltages...

I have no clue where to start testing, and could really use some guidance, as well as maybe schematics for the drive.

Thanks in advance

In further clarification, it's a Varidyn ADB/F 380.60 Drive unit.

At a minimum, The identification of the LED's and Variable resistors would be awesome. I do have the schematic books for the lathe itself. But short of confirming the proper wiring to the drive, I'm stumped.

X and Z are just fine, and work flawlessly. As does the turret. So I believe the spindle/drive is a valid focal point.....

Thanks.