I’ve got a Replicator 2 with about 580! printing hours. It suddenly started slipping in the Y direction.
- The belts are all tight, except for the short vertical Y belt and I can find no damaged teeth or unusual wear.
- And the XYZ step motor cable has been replaced already with a crutch to help it not be bent in the future.
- The gantry has been aligned.
I’m not sure how to continue.
Video of slipping - note the sound of the slip when the carriage reaches the end of a run and changes direction in the Y direction.
UPDATE: I replaced the short Y belt with a spare salvaged from an old bot. Tighter than the original but not as much as I want. ALSO IT STILL SKIPPING AROUND. 
also this bot is at 580hrs :\
Things I have done:
-Greased
-Tightened all belts
-Realigned gantry
-Switched Y motor with a spare
-Switched short Y belt with spare
Did you check the motor pulley that moves the belt? It may be possible that the pulley is stripped or missing a few teeth causing the slip.
I have seen this before, long time ago… i think we flashed the software.
/GN
If none of the other things resolve it, wiggle the power/signal cable to the Y motor while the printer is running and see if it happens. Rep 2’s have had an issue with wires in the cable breaking and causing intermittent opens which results in jumps. I have had it happen on the x harness twice, not the y, But you might check that out.
We had a similar problem in few occasions. The first time the cause was a defective SD card. Formatting the card fixed the problem at first. However, we replaced the card with a new one eventually. The second time the cause was a MakerBot Desktop software update. We downgraded the version and that fixed the problem. The third time was a broken cable.
after watching the video ( wouldn’t play when i tried it four days ago) it looks like the x movement is having the issue.
I also recommend checking the cable running to the X motor on the gantry .
Looks exactly like the problem I had with the flat cable to the stepper motor. Over time it gets weak and causes this error. You can replace or try to splice it and it will all go back to normal : ) Took FOREVER to diagnose the problem. Try this . . .
I’ve looked into this more. I also replaced the motor cables when I replaced
the end step cables, however both came from a salvage bot with 200+ hours.
It does skip in both X and Y.
I won’t do it in jog mode, probably because it’s too slow. More Speed = More skipping.
It even skips during the first raft layer. Other than the raft layer, the skipping happens
most when the carriage is changing direction, instead of at random intervals like static.
Confusing because at low speeds it acts like static and a broken cable, but at faster
speeds it acts like a belt/pulley is slipping.
Maybe, I have both problems.
