Z-axis stepper issues

[ahaidet]

I have a M2 that was shipped March 2013. I have upgraded it to 24V and Dual extruder over the years. Recently has some issues with M999 errors and poor print quality that as far as I can tell were related to the thermistor wiring. I replaced both the thermistor and all the wiring leading up to the Rambo. Went to print my first test print since the repairs and now the Z axis won't move up only down and makes terrible noises. I did not touch the z-axis stepper in any of the work I was doing. The machine was unplugged and powered off while any work was being completed. I shut the machine down and powered it down and checked the z axis stepper wires to make sure I hadn't bumped them loose and they looked good. Closed it up and tried again and still having issues. Both X and Y axis jog and home normally with no issues.

I did read a thread on this forum about M2s shipped in early 2013 having different Z steppers that ran hot.

viewtopic.php?f=7&t=1810

If this was the only issue I was having I would say that I clearly need to change the Z stepper.

While troubleshooting the Z issue I tried switching from the one Z driver to the other ( I am not sure if this really proves anything) but the issue persists.

With the other issues I have been having I feel like I can't rule out the Rambo board being the cause of all my issues. As I mentioned in my previous thread the electronics fan did die from a piece of filament being jammed in it and I am not sure how long it was like this. It was right before Christmas and I was printing parts for gifts daily at that point. As soon as I noticed it was failed I replaced it. (I would like to think it was only a print or so that it was failed but I can't be sure)

Here is my thread from the thermistor errors:

viewtopic.php?f=7&t=5314

How can I check the Z stepper or Rambo to narrow down which is truely the problem?

I am also contacting MakerGear Support as well.

[ednisley]

How can I check the Z stepper or Rambo to narrow down which is truely the problem?

Measure the resistance of the stepper motor windings. Power off, unplug the Z stepper cable at the RAMBo, measure between the outer wire pairs: [A A B B].

If you measure about 28 Ω between A-A and also 28 ohms between B-B, then you have a high-resistance motor. Replace it before proceeding.

If you measure around 5 Ω for those pairs, you have a new motor. That's unlikely for an early 2013 M2, unless you replaced the motor as part of the 24 V power supply change.

If you measure different resistances for A-A and B-B, then there's a problem with the motor. That is highly unlikely.

Report back with resistances and we can proceed from there.

[ahaidet]

I measured the pins above the resistance between the 2 red pins is 29.3ohms and the green ones measure 28.3ohms.

Makergear doesn't list the zstepper on their store anymore. I thought they did at one point?

I was able to get the printer to run again. I am not sure what I did different. Print quality is still not great vertical walls are still caved in. I have replaced the thermistor and all the wiring now.

[ednisley]

doesn't list the zstepper on their store

Give 'em a call to get walked through the choices for a new Z motor; they'll know if you need other odds & ends, too.