Juddering/skipping X axis when y axis not on end stop. HELP!

[James Avery]

Hey everyone!

Our replicator 2 has developed a new fault today where the x axis judders and changes direction randomly. 

The funny thing is this does not occur when the Y axis is at the end position. So basically what happens when I "home axis" is that the x axis judders and skips around making a terrifying loud sound until the y axis reached the end stop, and the x axis moves as normal.

So far I have tried:

• Reuploading firmware
  
• Swapping the little botstepper PCBs between the x and y axis
• Replacing the Motor on the X axis

still no change.

I checked the continuity on the cable between the motherboard and the stepper motor on the x axis (does this cable have to be under such tension!?) and found that one of them was broken, so I made a kludgey fix with another wire. Still no luck. This break maybe only occurs when I was swapping the motors or cables.

Any thoughts on what to try next?

Cheers

[Damian Gto]

Did you change all cable on the x-stepper?

I just had bad wires and I cut them off and put a whole new cable there and it works for me now.

[Eighty]

It's a known issue.  Your X axis ribbon cable is broken, right on top of the stepper (as it exits the little nook behind the roll pin).  On mine, there were actually two broken wires - the two outermost ones.  So you may need to do another splice to be back up and running.

 

Then order a replacement cable from MBI.  If they don't replace it for free, it will be $15 plus shipping.

 

When you get the new one, wrap a couple of turns of blue painters tape (or similar) around the ribbon at the failure location, so as to stiffen that area.  And keep your old (repaired) cable as a backup.

 

By the way, are you any relation to the Texas jeweler "James Avery"? 

[Eighty]

I should have mentioned:  This particular break is hard to diagnose if you haven't heard of it before.  The shuddering can happen randomly, or in a repeatable fashion - it just depends on how you flex that ribbon cable.

 

You'll have to remove the right side PVC cover panel to see the ribbon cable and roll pin. 

[Jeff Johnson]

To test, mark the cable where it flexed the most (mentally or with a sharpie), then loosen it from the roll pin so it is hanging free and then go to utilities and jog back and forth in the x axis. While doing this wiggle/bend the cable. If at any time the stepper stops, hiccups, or does anything unusual then that's the problem. That's how I found mine. 

As everyone mentioned it is a somewhat common issue.

Jeff

[James Avery]

Eighty, once again you come to our aid! I will do another splice of the whole bloody cable and see if that solves it!

Im guessing a replacement will come under the old "wear and tear" argument. MBI gave us this when our extruder block arrived warped so the plunger was not held in place properly. 

I'm afraid I am not related to the jewler! nor am I related to Uncle Phil from fresh prince sadly, that would be fantastic. 

[James Avery]

Thats a good plan mate, I guess I may have done the splicing slightly too high up from the place it actually broke. 

It seems like I have had all the "common" issues, but dont find out that they are until I beseech the good people of this group.