Stepper Gear is malfunctioning

Did you check the things I recommended?

Sounds like the hot end. Possibly even a wire loose that heats the hotness on the top part. Check the wires on under the top cap and make sure all are in place and tightened down. Then make sure the hot end wires are tight and making contact. 

Then test it by loading filament.  

Cheers and good luck

As others have said, it may well be that your extruder is not getting hot enough due to bad connections or a faulty heater.

What others haven't mentioned is that just being able to pass a 0.4mm wire through the nozzle doesn't mean that your nozzle isn't blocked. There is a 1.8mm melting chamber just behind the 0.4mm orifice. If this chamber is clogged the nozzle will not work properly, and the additional back-pressure could cause stepper motor stuttering. Soaking in acetone (if the nozzle has only been used with ABS) will soften any material, and then gently twizzling a 1.8mm or 1/16" drill bit around in the melt chamber will clear it out. You can also soften the material with a torch - don't overdo it, just get it warm enough to soften the plastic, not melt the brass, lol. You should be able to look into the back end of the nozzle and clearly see the empty melt chamber.

Here is the nozzle cross-section, courtesy of Yosemite Sam:

nozzle.jpg

Also if YOU still think it might be the cable you can always take it and swap the ends. Put the top to the bottom and the top to the bottom. It has worked for me before, and when that one stopped working I just cut two inches off both ends of the cable and re-seated it. It's been working ever since.

I know you have a lot of things to try so good luck. This will at least eliminate the thought of the ribbon cable.

Thanks again for the suggestions.  I thought I might find time to try follow up on some of the suggestions.  But not till tommorow now.  Worst thing is having these printers in a separate offsite space.. I'll live of course.  But I did try making sure that all the electrical junctions on the feeder assembly were seated properly.  I only soaked the nozzle overnight, I haven't tried to insert a bit into the nozzle.  I don't have a wire as suggested by Julia to fische the feeder tube.  Hoping I don't need to buy that too at the moment.  But I'll figure this out but man just didn't expect to have this much troubleshooting involved.  realize I need to purchase a couple of nozzles to have on hand and wondering if I should look at a heater too.

Anyways I made a video showing the extrusion without the nozzle and with.  I'm guessing my nozzle is still the culprit or the heater isn't getting hot enough.  Sorry I didn't have time to edit the video more so it's a tad long but I wanted to show how much extrusion length comes of one cycle of fillament load without the nozzle to see if that looks correct compared to others.  Have nothing to compare to.  Also with the nozzle on which obviously invokes the ratcheting.

Thanks again everyone! i do appreciate it.  I might need to order a hotend and nozzles now.

Ladies and germs, for your viewing dis-pleasure may I present "still clogged II"  http://co3dprints.com/m200/m200_stepper2low.mov

Oh Julia thank you for that cutaway,  I see what everyone is trying to tell me about the wire vs. the cavity that holds the liquified Zmaterial.

Ladies and germs, for your viewing dis-pleasure may I present "still clogged II"  http://co3dprints.com/m200/m200_stepper2low.mov

That looks perfectly normal to me.

We now have ZHIPS in stock, and I believe we have an ULTRA-T shipment on the way, so it will all be in stock soon. As for spare parts, we are having to catalog all the parts we will need and come up with a pricing list for parts to sell as well as RMA/replacement parts. Give us a few more days to get the catalog up and then we will be ordering parts from Zortrax for stocking. Making our own warranty has been a lengthy process and determining what parts are consumable and what not is quite the hassle.

Quick update.  The nozzle is either not heating up all the way or the heating element is not quite right.  However!  I took a couple of drill bits and cleared out the nozzle really thoroughly to the point slightly digging in or chamfering the liquid chamber to the down spout of the nozzle and there was a tiny bit of addtional hardened abs it appears in that chamber that came out.  After several rinse, repeat times of this.  the flow was almost back to normal.  The stepper gear is still ratcheting but way less and sometimes smooth.  So thank you all very much.  Still need to clean out more and investigate.  Just normal job this week has kept me away from further analysis but think it's a bad nozzle or heater element.  I haven't taken the heating element off as looking at it it's not easily clear to me how it disassembles and I ran out of time.

The profile of the nozzle was very helpful as well and letting me realize that perhaps the chamber wasn't as clean as I thought.  Is there a downloadable manual that shows how the entire feeder mechanism is assembled?  If not, that would be helpful to new users.

Quick update.  The nozzle is either not heating up all the way or the heating element is not quite right.  However!  I took a couple of drill bits and cleared out the nozzle really thoroughly to the point slightly digging in or chamfering the liquid chamber to the down spout of the nozzle and there was a tiny bit of addtional hardened abs it appears in that chamber that came out.  After several rinse, repeat times of this.  the flow was almost back to normal.  The stepper gear is still ratcheting but way less and sometimes smooth.  So thank you all very much.  Still need to clean out more and investigate.  Just normal job this week has kept me away from further analysis but think it's a bad nozzle or heater element.  I haven't taken the heating element off as looking at it it's not easily clear to me how it disassembles and I ran out of time.

The profile of the nozzle was very helpful as well and letting me realize that perhaps the chamber wasn't as clean as I thought.  Is there a downloadable manual that shows how the entire feeder mechanism is assembled?  If not, that would be helpful to new users.

You are getting closer.. Strange that this happened though.. The hot end is just held on by the two set screws on the front.  (above the heater block) You've already had the motor off so that's pretty much it..

During a normal print when everything is running as it should, does the stepper not skip at all?  I noticed after donig the cleaning outlined, that when trying to put a raft down which is a considerable more amount of ABS the stepper was 'missing' still and then almost inpercetibly at times during the actual slower feed of the model but a bit.  My test part is the simple hooks from thingiverse that keep the feeder hose and ribbon cable together.  it's a quick part that if when I'm testing can actually sorta complete even with frey ABS etc.  Anyone have calibration parts they would recommend that are fast to print and descent checks of mechanics before a long print?

During a normal print when everything is running as it should, does the stepper not skip at all?  I noticed after donig the cleaning outlined, that when trying to put a raft down which is a considerable more amount of ABS the stepper was 'missing' still and then almost inpercetibly at times during the actual slower feed of the model but a bit.  My test part is the simple hooks from thingiverse that keep the feeder hose and ribbon cable together.  it's a quick part that if when I'm testing can actually sorta complete even with frey ABS etc.  Anyone have calibration parts they would recommend that are fast to print and descent checks of mechanics before a long print?

The stepper should never skip. Sometimes it will putting first layer of raft down if it's too close to build plate. After that it should stop. You can try to put your test part in a different spot and try it. Just move it to a corner in Zsuite.

OK.  Good to know.  Will try in other locations

Skipping stepper motor, still sounds like a bad ribbon cable to me. It is really the only problems I've had with my printer after a year. Well that and the fans. Even if the ribbon cable is completely seated if the wires are bad it doesn't matter. The way mine worked, was in some positions it would feed perfectly and then in others it would oscillate back and forth. When I took the nozzle off it would feed perfect, but when I would put it back on It would oscillate back and forth again. I attribute that to no matter if the nozzle is clean or not it still put excess back pressure on the stepper. In conclusion the back pressure along with a bad ribbon makes the stepper oscillate. 

I can almost bet if you put a brand new nozzle on your machine and printed in the same location you are now you would have the same problem. But if you move your test print location like Kyle said then it might just print again, which would mean bad ribbon cable unless you have a very un-level or clogged perf board, which is not the case because yours want even feed the filament 6 inches above the print bed.

Disclaimer: I am by no means an expert I just want to see you get back up and running. Also I only ever speak of things that have happened to me, so if someone else has a different take then so be it.