Need Help!- z-axis drifting down and errors 409, 449

[Dale C]

Hello everyone, i am completely new to this so hopefully I can do a decent job of explaining the problem. I just purchased a 1993 Milltronics Partner One with a Centurion V controller the machine has been converted to single phase. The machine was under power and running great when we picked it up. Moved it 100 miles and set it up in our hot rod shop.
When we powered the machine up and went to home it the z axis started to drift down and the machine e-stoped. When we would hit the reset button the x and y would jump and the z would start to drift until it e stoped.
I checed all the fuses and visable connections and swaped the board for the z-axis with y, still no luck. I then pulled all the covers ran all three axis near center travel and found the home and overtravel switches were at the same location on z and y were damaged. I adjusted Z and repaired y. The machine then seemed to run fine, we entered a new parameter for the tool changer due to the change in the home location and it changed tools fine.
After several tool changes to check operation when the tool changer came over (it hits hard we may have to much Air pressure) the screen went to a doss page and the machine stopped. It is now back to the same symptoms z-axis drifts down on cycle start for home and machine E-stops. Sets errors 449 409 and 450.
Here is a link to the machine http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWNX:IT

I am very sorry about the book on my first post.

Thanks for any help, Dale

[ZZZZ]

Whenever the Z drifts down, it means the control thinks it is re-set so it turns off the brake in the Z axis motor but the drive doesn't take over. Then Z moves down until it exceeds the Excess Error value and the control e-stops and turns the brake back on.

You will want to look for something that keeps the Z axis from re-setting. I'd start by swapping the Y axis drive card with the Z card o see if the problem moves to the Y axis.
If it stays with Z, check for the analog signal at the drive card.

As far as the tool changer banging when the carousel comes in or goes out, it usually means the cushions in the air cylinder have gotten dried out and no longer slow the piston down at the ends if the stroke. Check the air lubricator to make sure there is air tool oil in the bottle and add an ounce or two of oil to the air line down to the tool changer. You can go to MDI and cycle the arm in with an M23 and an M24 to put it back out. There also are some needle valves to control the air flow to the cylinder, you may have to adjust them.

[Dale C]

Thank you,
I have changed the cards and the problem does stay with Z. I am not sure how to check the analog, I have searched for a schematic with no luck.
I think we have the changer sorted out, we run the shop at 160psi and when we hooked up the machine I didn’t think to regulate the pressure down. The only reason I brought it up was because everything leads towards a loose contact. It seems to be intermittent and happens with any movement or shock on the machine.
I can call someone in if necessary but I would like to get as familiar with the machine as possible. I do a ton of electrical and computer diag on the cars but I dont have a starting point on the machine. I have searched for some type of operating system description with no luck, I am not even sure I am using the proper terminology.
Just a list of actions taken in what order what help a ton.

Thank you again, Dale

[ZZZZ]

You may want to put a block between the table and the head casting (not under the spindle) while you trouble-shoot your problem to keep the head from falling down onto the over-travel switch.

Pin 11 on each axis Amp connector is usually where the analog comes out of the cardcage. With the control reset and you have pressed F1 HOME and cycle start, check for DC voltage between Z Axis-11 and ground.

Other things to check are:
The acroloop axis cards are properly seated in their slots on the motherboard and all the ribbon cables are tight
+15 vdc between TB26 and TB22
-15 vdc between TB27 and TB22
CR1B is functioning properly - it should pull in when the machine is reset

Good luck

[single phase]

I agree with ZZZZ, check the voltages of all the power supplies! Especially the PC power supply voltages and the 24V buss.

[Dale C]

Thanks again guys,
We have been slamed in the shop so i have been trying to work on it as I can. I went to check it today and everything came back on line. I will still check all the items you listed as soon as I can but i am afraid it may be some weird intermittent issue.
Another thing I noticed today after the machine homed I tried shaking the contacts and boards to duplicate the problem with no luck, but everytime I e-stoped the machine the Y travel would jump forward between .300-.500 and when i reset the estop it would go back about 1/2 the distance it traveled forward?
I am hoping I can duplicate the loss of the Z reset to make the diag a little easier. I know it didnt magicaly fix its self.
Thanks again for all the valuable info, I will report back as soon as I can run the tests.