Dynapath Delta 20 / Servo Dynamics Axis Lag Problem

Hi, I just recently picked up a 1988 CnC Ostmach Mill KR-V3000 (looks like King Rich KR-V3000 castings) with a Dynapath Delta 20 control. I've been working on getting it cleaned up and tuned. I've set the CNC control up to run off single phase and hooked the spindle up with a vfd, but have yet to make any chips with it. It's my first machining tool bigger than a drill press, so while I've been reading up on it for awhile, I don't have a lot of hands on experience.

Anyway, to the problem, I've been trying to get the axis lag under control for a few days now, It's got a Geetek drive on the X, currently reading 0.0012", and Servo Dynamics drives on the Y and Z (axis lag of .0062 and .0031 respectively), which is significantly higher than the numbers of +/-0.0002" I've been reading that it should be.

So far I've,
1. Attempted to tune the balance pots, the X axis went down from about .003 to the current .0012 but I was unable to take it further, I was only able to see a change of about .0006 either way with the pot on the Y axis, and Z was no better.

2. Checked the Y and Z axis for mechanical problems, they seem fine, both can be turned by hand with no great effort.

3. We hooked up a scope to the tp6 test point and tuned the Y drive as it says in a Servo Dynamics manual I found, tuned various pots to bring it into a fairly linear deceleration curve, and reduced the oscillations after deceleration. This didn't appear to have any effect on the axis lag however, I did notice the tach line seemed rather noisy, but I'm not certain it's not just electrical noise being picked up from elsewhere by the scope.

Any help would be greatly appreciated, I'd really like to be able to get these drives going if it's possible.

Edit: One other thing I forgot to add, is that it has a tendancy to move the bed around a bit as the control is booting up, which then stops once the control has started, I'm not sure if that is normal or not.

try contacting dynapath they are pretty good giving help over the phone and then zps, ask for bob, is pretty familiar with that control. you can get their numbers at there web site
then there is this fella george @ g&o controls in california, he used to work for dynapath, believe he rebuilds the old boards. i will private message you the numbers i have for him. check your inbox under the notifications at top of page.

Thanks for the numbers, I will keep them in mind for the next time.

As an update, we spent a couple more hours yesterday poking through it, and we starting measuring the sig input to the servo drives.
To test it, we turned the emergency stop on to disable the servo drives, at this point the computer still tracks the axis lag and outputs a voltage to sig to try to bring it to zero. You can then turn the motor by hand and watch the signal level change, it turns out that we had a 250mv signal when I turned the motor to the position that read 0 axis lag. This seemed a bit odd, and after some checking, we found the ground on the dynapath computer was floating ~250mv different to the servo ground. This then led to finding the bolts that are meant to hold the computer chassis to the rest of the box were loose, they seem to be a major ground point for the computer as tightening them fixed most of the problem.
At the moment the computer cards are still different by ~20mv compared to the computer backboard/motherboard and chassis, but it's got the axis lag down to the point where the balance pots can bring it to 0.

So long story short, if anyone else has this problem, where all three axis are a long way off (even though mine were not off by the same amount), it's worth checking the grounds to make sure.