CPU7 Controller starting to fault

[kevincnc]

Hi folks,

The controller on my Bridgeport clone mill started having servo faults recently. Here is the config file-

CNC7CFG.TXT

(7.88 KiB) Downloaded 1 time

The first couple lines read as follows:
CNC7CONV v. 7.09 - Centroid configuration file utility
CNC7 M-40 v. 7.09 setup file for CPU7 serial number 130960832

On the cabinet, it says Model M40, Serial #K-1420

Here is the problem: While running a program, either the X or the Z axis will stop very briefly at random, and then jerk ahead to catch back up to where it's supposed to be. This can obviously be a bad thing during a heavy cut. Sometimes is just stops and faults, which I assume is because it is outside of the allowable error.

Here are a couple of screen shots of errors. I believe that each has occurred on both X and Z. I'm not sure if Y has had any problem. I hope the pictures aren't sideways like the preview shows. If so and someone could tell me how to fix it, I'll do that.

Here is the machine. The controller has the original computer running on DOS, on a physical hard drive. I guess it's kind of amazing that it still works at all. I've always mounted it on the wall to isolate it from vibrations.

Here is the controller. So far I have unplugged and re-plugged everything into the computer, re-seated the card, and blown out everything else in the box. I don't know what else to do.

Do I have any chance of finding and fixing a problem here? It's just for hobby work, so I don't want to spend a lot upgrading it, but will look at that if it's the only choice. If I left out any necessary info, please let me know.
Thanks,
Kevin

[eng199]

It could be a loss of Vm power due to loose connections, or similar problem. The heavy gauge light and dark blue wires at the servo drive should be checked for around 100VDC.

[cncsnw]

My guess is you just need to clean the servo drive logic power supply connections.

See http://www.cncsnw.com/ServoLogicPM.htm

[eng199]

My guess is you just need to clean the servo drive logic power supply connections.

I was thinking there would be a drive fault on that system if logic was lost. Is that incorrect?

[kevincnc]

Okay thank you both! I'll check and clean those connections.
Kevin

[cncsnw]

I was thinking there would be a drive fault on that system if logic was lost. Is that incorrect?

Sometimes, but not always. Usually, the first symptom is the hesitation and jump to catch up.

Maybe the +/- 12V fades before the +5V.