Folgertech Prusa I3 : X axis movement problem

I'm new to 3d printing, and this is my first build. I'm building the Prusa I3 from Folgertech, and having a problem with getting the X axis to move normally. Has anyone encountered this problem?

What's happening most often is that when I try to home the X axis, the carriage lurches a few centimeters then stops, usually with a start-stop-start motion, and the motor whines after stopping, until I do an emergency stop. When I try to move it RIGHT, every command from 0.1mm to 50mm moves it less than a mm. When I try to move it LEFT, 0.1mm moves it about 1mm, 1mm moves it about 10mm, 10mm moves it 2-3 cm, and 50 makes it do the start-stop-start lurch with whining. It seems odd that there would be such a difference in behavior moving left vs. right.

Or sometimes the X axis fails to respond at all, but the motor may whine until I give it another command. I don't see "endstop hit" in the log while doing any of this, just "ok".

The other axes are responding to commands normally.

I switched the X motor with a known good motor, then also switched out the stepper driver, and motor cable. The problem continued with each change. I think the belt tension is fine. I can move the carriage manually very smoothly. I've tried reversing the direction the motor cable is plugged into the RAMPS board, but that only reversed the direction of the funky behavior.

This happens even with the firmware downloaded from Folgertech's Google drive, with no changes, so I know it's not from a change I made. I'm using Repetier Host.

So it's not the motor, it's not the motor cable, it's not the stepper driver. What else could be the problem? Could it be a bad RAMPS or Arduino board?

Edited 1 time(s). Last edit at 05/19/2015 03:09AM by CraigMoberg.

Try to connect the x-stepper to the y-driverboard and see if it works then.

Sometimes the jumpers on the RAMPS don´t provide good connection.
Your x-driver might be in a wrong stepping mode and can´t cope with the signals it gets. ( too fast )

What about the potmeters on the Drivers? Did you adjust them?
-Olaf

Thanks, Olaf. That gives me progress. The X carriage moves smoothly and at the right amounts when I connect the X motor to the Y stepper driver board -- mostly. Sometimes it still fails to respond, though I can hear the motor trying. Would checking and reseating all the jumpers help?

What do you mean by "Your x-driver might be in a wrong stepping mode"? What would fix that?

I adjusted the pots initially to the values in the Folgertech manual (X - 0.350V, Y – 0.550V; Z – 0.350V; E – 0.350V). I used a friend's multimeter then, but just checked them with my cheaper multimeter and had trouble getting consistent readings and settings. So I'm not confident of those settings now. Would bad pot values cause the behavior I described? I'm not experienced with motors or electronics, so I'm in the dark here.

Craig

If you read inconsistent values at every drivers potmeter, you probably have trouble with the 5v supply on the Mega board?
If it´s only the x-Driver, the potmeter might be bad or the whole driverboard. You must not plug/unplug Steppers while power is on, that can kill the Drivers.

With wrong stepping mode, I meant bad contact of the Jumpers. A motor can´t cope with gazillion steps/second when it´s in fullstep or 1/2 step mode, but in 1/16 mode, it could follow the stakkato
-Olaf
PS: it´s always a good idea to have a few spare drivers at hand. You might want to look for a set of new "drv8825" and keep the A4988 as backup?

Folgertech overnighted me a new RAMPS board, and everything's moving smoothly now. So either I got a bad board, or I did something stupid to it. Thanks for your help, Olaf!

Edited 1 time(s). Last edit at 05/21/2015 04:20PM by CraigMoberg.

This thread is very helpful. I am having the exact same issue. I just contacted the company.

Thanks for posting it!

Zxqueb, did you get a resolution? Right now everything works on my printer except for the X-axis. I get nothing when hooked up correctly. However, if I move the X-axis connection to the Y-axis connector it works fine. When I switch the motor drivers between X and Y the problem stays with X. I'd rather not pull the RAMPS board, but give the quality of the build on that board it looks like that might be the culprit.

Is the log you guys are referring to the Repetier log? I don't get much useful information in mine. Is there a more verbose option?

Thanks
Glenn

Glenn,

It seems that we have the same thing going on. Everything on mine works fine except the x which also works fine for me switched to the Y. I have tested the extruder, all axis motors and an added an lcd screen. All of that seems to work (although it is hard to say completely without the x working).

I contacted Folger Tech and they are mailing me a new RAMPS. As fixes go, it isn't too bad if it works. I can't imagine it is more than a 5-10 minute swap. I will let you know if it resolves the issue when it gets here later this week.

Matt / Zxqueb

Quote
Groundswell
Is the log you guys are referring to the Repetier log?

Yes. There are Debug Options at the bottom of the Manual Control tab (if “Easy Mode” is disabled) that let you specify what you see in the log. Turn on Info and Error, and maybe Echo.

Thanks guys. I don't know GCode, but when I click one of the manual buttons I get three commands and three OKs. This is the same as the commands that work, so I am going to assume for now that they are OK. I noticed the same bad manufacturing that a number of people have commented on here. I pulled the board and resoldered some of the connections that appeared bad. However, most of those were on working channels. Still reacts the same was as before. I'll contact Folger directly.

Thanks
Glenn

Ok. I got the new RAMPS this afternoon, installed it, and had the same issue.

HOWEVER, I did some more poking around and experimenting and think I managed a fix. I went into the arduino code (configuration.h) and changed the line "#define X_HOME_DIR 1" to "#define X_HOME_DIR -1" Then, I switched the endstop to the other side of the machine.

It has now homed correctly multiple times and it just did this:



So, yeah. Lots of runaround for a simple fix. I don't know enough about the Arduino Code to know why it wasn't working the other way. I'd be interested to know theories from those of you smarter than I.