Z Axis Stopped on My OmniSign Pro 3000

[Amos De Pasquale]

My Z Axis suddenly stopped working on my Laser Engraver,
1. I tried another Microstep Driver, same result no Z axis
2. Tried isolating one motor at a time(there are two in parallel) could not get either motor going.
3. Reloaded LaserCut 5.1, still the same result.
4. Took the load completely off the motor, motor would not move, but power getting to the motor because when on the motors are locked and won't move.
5. When I click on Z- or Z+ you feel the motor respond but not turn-you hear a slight clunk.
Any ideas or advice please.
Thanks Amos

[Robert Schmiede]

​Amos mine did exactly the same,tried all what you said and after a lot of hair pulling found a loose wire,fixed.

[Amos De Pasquale]

​Amos mine did exactly the same,tried all what you said and after a lot of hair pulling found a loose wire,fixed.

OK Robert, next in line I will do some more circuit tracing, in fact I have considered changing that particular loom!!! Will post my results once I have tried it. Meanwhile, if somebody has other suggestions, please let me hear them.

Amos

[Amos De Pasquale]

I have now proved that the motors and and the wiring to the motors are ok. But still have no Z axis????????? help!

[Keith Colson]

At this point I would put an oscilloscope on the input and output of the stepper driver and look for a stepper pulse train (square wave). Also get the datasheet for the stepper driver and see if the power etc is correct. With the data sheet it will be easy to identify which pins you should scope.

Cheers
Keith

[Richard Rumancik]

I have now proved that the motors and and the wiring to the motors are ok. But still have no Z axis????????? help!

Seems like you are doing a systematic job of troubleshooting so far. When you say you have proved that the motors are ok, what exactly do you mean? Have you actually got the motors to run with a driver attached or is this based on coil measurements?

If the motor and wiring is truly okay, and you have swapped drivers, then you are running out of possibilities. . . is it possible that there an intermittent connector where one coil is not being properly powered?

Does the driver board have two independent driver circuits or do they just connect two motors to the same driver outputs? If they are independent it is unlikely that two outputs, harnesses, or connectors would fail at the same time so it would seem that the failure is at or before the common point of both motors.

When you say you took the load off the motor do you mean you disconnected the z-axis mechanics from the shaft? That would rule out binding in the z-axis. I assume you have checked that the z-axis turns freely.

[Bill George]

My Z Axis suddenly stopped working on my Laser Engraver,
1. I tried another Microstep Driver, same result no Z axis
2. Tried isolating one motor at a time(there are two in parallel) could not get either motor going.
3. Reloaded LaserCut 5.1, still the same result.
4. Took the load completely off the motor, motor would not move, but power getting to the motor because when on the motors are locked and won't move.
5. When I click on Z- or Z+ you feel the motor respond but not turn-you hear a slight clunk.
Any ideas or advice please.
Thanks Amos

I am a little confused. You have one driver board for two motors? You can disconnect each motor and let the other try to run but neither works? One power supply feeds both motors? Your driver board gets signals from the controller and is that wiring correct, wires tight and in place? That looks like the common place where it could keep either or both motors from working.

[Amos De Pasquale]

Thanks for the feedback,
There is one driver, and it drives two motors in parallel; This moves the table up and down evenly.
How I proved the motors and wiring are ok, I connected the wires to the Y motor driver, and was able to run the motors.
When I say I disconnected the load, I took the belts off the the two motors, that way there was no load on the motors.
I also connected an extra filter capacitor across the 40 volt line, just in case there was too much ripple on the line, still the same result.
I will get a CRO (Cathode Ray Oscilloscope) and do the checks suggested.
I have also reseated the driver card in the computer!!!!! same result. Also reseated the cable from computer to Laser Engraver.
I have metered the 40volt line and that is ok.
A digital meter set on AC shows that the voltage to the coils actually goes up and down as per the Y and X drivers.?
Very puzzling, CRO is next thing.
Thanks for the input so far, if I have not made clear on any point, just ask me the question again and I will try to answer in more detail.
Amos

[Robert Schmiede]

Amos,when I had my problem I disconnected the belts to take the load of the stepper motor and they would run, put the belts back on and they wouldn't run, not enough voltage going to the stepper motor,found loose wire,fixed.

[Amos De Pasquale]

Thanks Robert, I did that but motors still did not turn, I took the leads of the Z driver, moved them to the Y driver and motors moved--there I deduced that the wiring was ok, I swapped the drivers over, set the dip switches appropiately and the Z axis with the newly installed "Y" driver did not work. Swapped drivers back to original, Y and X ok, Z no go, I am beginning to suspect software or the actual card in the computer.???!!! Amos!!!

[Robert Schmiede]

Red Dot should be able to help you out, feel your frustration Amos.

[Keith Colson]

Red Dot should be able to help you out, feel your frustration Amos.

Best comment this year haha!

[Amos De Pasquale]

Keith, you beat me to it!!! s-e-r-v-i-c-e not in RED Dot vocabulary, If I wasn't an Electronic Technician I would be really stuck, hence me asking for advice and hints from a Forum that has helped me greatly. Amos

[Amos De Pasquale]

Keith, I scoped the input to the driver, no square wave, compared it to the x and y drivers, I now need to check the wiring from the connector back to the computer, I will search the net for the pin breakout of the connector and also of the MPC03 Driver Card, Thanks, Amos

[Keith Colson]

Hi Amos

If you have a scope now, that is great. There can't be many wires. You need to find the presence of a square wave coming out of the microcontroller that goes off to the stepper driver. There should only be half a dozen wires to check. Don't forget the stepper pulse train will only be there when the motor is "supposed" to be moving.

I found this, is that what you have?
www.leetro.com/english/down/MPC03LV_LH%20User%20Manual.pdf (http://www.leetro.com/english/down/MPC03LV_LH%20User%20Manual.pdf)

Note that if it is opto isolated, there should be 5 volts present on the common pin otherwise the open collector driver will have no voltage to pull down which results in no square wave on the PUL (pulse pin)

I would also check that the Z limit switch is working correctly. You can scope it on the microcontroller boards input connector and see it change state when you actuate it by hand.

If all the electronics is correct then you may need to delve into a firmware update or a driver update. Plugging the USB into another port is also a good thing to try. Sorry if some of this info is not right for you machine. I have not seen one before.

Good luck
Keith

[Ray Scott]

I have been following all the testing and info on this problem. I might be able to help you direct to the problem.

There is a buffer-driver chip on the MPC-03 card. I would expect that one of the output pins is damaged. This pin is a direct connect to the "step" command on the stepper motor amplifier. Bad step pin ..... No motor movement.

I am sure that the MPC-03 card is out of production for a few years. If you can't get this card working, finding a new MPC-03 card will be nearly impossible.

A last ditch attempt for a dumb fix.... Check the 80-pin cable to see if you have bent any pins while connecting/reseating the MOC-03 motion card.

thanks ,
Ray Scott

[Amos De Pasquale]

Keith and Scott, I haven't had a chance today, but I will scope the o/p from the controller card, hopefully there is one. If there is an output, I will meter(ohms) the SCSI cable for continuity. The pins look ok, I have the pin layout for the plug. Failing this, I have a 6515 upgrade card that I have in possession for two years, but did not want to fix something that wasn't broken, now I may be cornered into doing the upgrade!. Thanks for the input, I will report back on what I find. Amos

[Keith Colson]

That's good advice Ray, its sounds like you know this kit. Amos, if you upload some photo's it would help.

Cheers
Keith

[Amos De Pasquale]

I am after an MPC-03 LV Laser Controller, does anyone have a spare???? Amos