Unresolved Annoying clog and unexplained issues with ribbing.

I've had problems with Z-ribbing since I got my robo3d. It severity comes and goes but everything I've tried has failed so I need some guidance. It matches the rod pitch (8mm but measure at 7.65...). Hopefully you guys can help me figure it out...

P.S. I have tried:
-Powering z stepper motors when not turning
-Reseating rods and couplers, both with the rods on the bottom, touching the motor, and above, not touching

 

You could try replacing the helical couplers. Otherwise I'd contact robo and see if they can help you solve it.

 

I was messing around with my z-screws to see if I could get them aligned better and decided to try rotating my Z-nuts (I had read somebody else did this) and lo and behold I got beautiful prints (I'll try to attach a pic), NOOO idea why. After printing some little plates to push the autolevel buttons, I tried to print something else but my z-offset was too low so it couldn't extrude and the filament broke. I didn't have my pliers handy so I tried to push the old filament through but it seems that it clogged further down in the tube so now I can't get it out either way. What would you guys recommend for my course of action? Do I have to remove the nozzle or can I take the X carriage come apart somehow? Thanks!

 

Well, I removed the whole extruder by removing the top two bolts and got the plastic out but broke the thermister when putting it back in the boot. I'll have to wait for a new one to arrive before I can see if the extruder itself is also clogged. It seemed like I could get filament all the way down to the heat block now so hopefully it's fine.

 

FYI: Never try to push a broken filament thru. You can heat it up ( the hot end) and pull it out to see if it your lucky day.

 

Well I've certainly learned my lesson now. Mostly it was just laziness, didn't have my pliers and the tweezers couldn't apply enough force, probably should have taken the hint . Anybody have an explanation for the ribbing solution?

 

Get rid of the couplers. They suck. Spend a little money and upgrade to steppers with integrated lead screws. You will be happy that you did.