MakerGear Forum

Hey all!

So, I have an issue with my M2.

Symptoms:
Extruder not extruding or retracting. In fact, it is not making any movements at all.

I have checked that the cable is intact, I checked the fuses on the RAMBo and that all cables are firmly attached.

What led up to this?

I had just gone through another levelling exercise and was a bit off in the Z-level. some 0.05 or so.

Instead of re-slicing, I found a gcode for setting the z-index in the firmware, which I thought could be a good start:

M212 Z<offset> was the command.
It was followed with a few different values, then M500 and M501 to store them.

Turns out it had little or no effect...

I DON'T think this could have caused the error in any way. I haven't looked at the code much yet, but it did not return anything from the printer.

It started with the VIKI2 display starting up, first screen seen, then into the menu and then totally white.
In fact, it looks like you were constantly pressing the button.

I have replaced the VIKI2 with my old VIKI and uploaded firmware again. Old VIKI doesn't seem to give any errors, but extruder is still not extruding.

Any suggestions to what I can measure to see if my driver is intact?
Any suggestions to how I can change my code to use the E1 extruder instead of E0, or does it need to sit an extruder in E0 to get E1 to work?
Just thought I could try and take the stepper motor out of the equation.

thanks,
Micke

askernas wrote:M212 Z<offset>

That seems to assume the presence of a "bed level sensor", whatever that might be on a Printrbot Metal, so the firmware might just fall off a cliff if that hardware isn't present or the firmware isn't compiled for that machine.

The G92 command sets the offset from the Z-axis switch trip point, which is probably a better hammer for the job. Rummage around in the startup G-Code to find it; changing the startup code will change the offset in everything you slice thereafter.

If the G-Code includes that command, then you can tweak the Z-axis offset by directly editing the G-Code file (with a text editor, not a word processor), adjusting the value in that command, and saving the file. That's not what you want to do all the time, but it's useful to re-run a file that needs a slightly different starting offset.

Thank you Ed!

I did rummage around a bit and reset my RAMBo by a M502 followed by M500 to store, and now it seems like it is extruding again!

Woohoo!

Will try with G92 and see what I can find! =)

Interesting that M212 can "break" your printer, but seems like issue is solved for now.

Will add my VIKI2 later on again to verify all is well and good.

Well.... I guess I was getting happy too soon.

It worked ... for about 5-10 seconds, then it stopped working again. *growl*
Well, back to the drawing board.

Might be a stepper driver that has blown... but ... we'll see!

askernas wrote:It worked ... for about 5-10 seconds, then it stopped working again.

That suggests the cable between the RAMBO and the extruder stepper motor has failed open, which isn't unheard of, or there's a slightly unplugged connector at the motor or inside the electronics box. I'd bet on the cable failing, though, because it flexes fairly abruptly while soaking up the X-axis motion.

Turn off the power, unplug the connector at the RAMBo board, and measure the resistance between pairs of wires. The two motor windings have a low resistance, so you should find two pairs of wires with low resistance and high resistance from each pair to the other. Most likely, you'll find only one pair of wires with a low resistance, which says the one wire of the other pair has broken.

On the happy side, a failed driver chip won't ever magically cure itself, not even for a few seconds, so the problem probably lies elsewhere.

Thank you, will try.

I did try the cables out with the beeper option on my multimeter, no shorts, and it does report contact, but if it is only partially, I don't know.

Will measure them as suggested, thank you. I hope it is a cabling issue.. easy to fix!
I just got to find a few connectors and crimp contacts, and I have no idea what that particular plug is called =p

"unfortunately" the resistance within the pairs match at 3 ohms, and high resistance between the pairs, so that was not the case.
I kept on measuring while bending the cable just in case, and it seems as my cable is intact, after all.

just gonna throw this out there........your hot end is preheated and up over 170deg right?

jimc wrote:just gonna throw this out there........your hot end is preheated and up over 170deg right?

Of course.

Since it's PLA, I'm using it at 200 degrees, but have tried over that just in case.