stepper motor jammed?

[sandy]

I've finally gotten to the first test print and was loading filament just fine, motor turning no problem for about 400mm, when I did Geneb's "pinch test". Bad idea, I could stop it a little, so I tightened the tension screws a half turn and then my motor jammed. At first I thought I'd tightened it too much, but no matter how much I loosend the tension screws it just makes awful noises and looks like it is having an epileptic seizure.
When I stopped the motor in Repetier, I could turn the gears just fine by hand. They feel good both directions, no blockage, no catches, no uneven turning.

Powered everything down, unplugged, powered back on (heated up extruder for motor test), same problem. Powered down again, switched motor to x motor plug on RAMBO (to test if it was the board) same problem (entered G1 X10 to test)

Every time I try to power retract or extrude with the motor it just stutters and complains loudly.

What did I do wrong? How do I reset a motor -- it was fine for ~400mm then blam!

thanks,

-sandy

[jetpad]

A few times when I thought the extruder was jammed on my machine, it was actually the Rambo board overheating. Try putting a fan blowing on the board to cool it down and see if that helps.

[cpunches]

You might want to check the crimped wires on the connector to the Rambo. I had a similar issue when I first got my printer built. I re-crimped all the wires and the problem went away,

[sandy]

Recrimping wires on the extruder motor fixed the problem temporarily, but when I plugged the X -motor back in, the problem came back.

I've had the electronics door open, and it happened when the machine was just started, so I don't think the Rambo board is heating up too much, but I am suspecting my electronics are the problem.

thanks,

-sandy

[sandy]

So, I recrimped the extruder motor connecter. Plugged it in and it worked, but only
until I entered G28 to home everything - then the X-motor started with the
same jammed behavior.

Disconnected, restarted, hit G28 - X-motor fine, extruder jammed.

Disconnected, restarted hit extrude 10, extruder fine, hit g28 X-motor jammed.

It seems, I can't run both at the same time.

btw: ( I make sure the extruder is heated to 230 before trying to run the extruder motor)

If I start moving X,Y,Z first, then the X-motor works but the extruder motor doesn't.
If I start moving the extruder motor first, then the X-motor doesn't work.

[Jimustanguitar]

I had a motor in my x-tower that was seizuring like this. Test the motor leads with an ohm meter. I had an open wire, and only one coil was getting power from the controller board.

[sandy]

Yeah, tried that, I have continuity. Both X-motor and extruder jammed all the time now. From the first time I connect - I can't move the X-motor at all. Heating up, I can't move the extruder motor at all. Think it could be the RAMBO board?

-sandy

[Broose]

Do you have a good power supply connection to the Rambo board for the motors/logic? Check to make sure you are still seeing 12V there when the motors are moving. The Motors and Logic are the lowest 2 connections on the power input connector, and if you haven't set the jumper on the board, the processor and other logic is running on your USB power, so wouldn't be affected by a poor connection there.

[Jimustanguitar]

I don't have any idea what behavior would result from this being wrong, but checking the power jumper was next on my list too... Try that.

[lordbinky]

If you have a multimeter on hand there's a check to see if the stepper motor is bad (not to say that it proves it's good though).

I don't have my kit yet so this is overly generalized and maybe someone else can elaborate on the specifics for the stepper motors in use.

For bipolar stepper motors (four wires) you want to measure the resistance on each coil, ex: black to green and then red to blue or orange <-> black & yellow <-> red , and the resistence of each should be the same if the coils are good.

For the unipolar stepper motors (five or six wires) it's the same thing but the your measuring each wire to the common wire, ex : brown to red , yellow to red, etc. It depends what the common wire is though.

You can also force steps in the motor by connecting a battery across the pairs but I don't know the specs of the motors to give proper instruction on it.

[lordbinky]

Sandy, did you resolve it or come to conclusion?

[sandy]

After following yours and others suggestions for testing, I think that the connectors to the extruder motor are loose. I need to recrimp them.

Do you know the part numbers for the crimp on header connectors and the 4-header? I'd like to order some more, and a crimping tool and do the whole thing over.

thanks for all the help, everyone. It has been invaluable.

-sandy

[Eaglezsoar]

Here is a link that shows the mouser part numbers for the connectors and pins.

http://forum.seemecnc.com/viewtopic.php?t=1794&p=11410

Crimper is here: http://www.amazon.com/HT-225D-Cycle-Rat ... B007JLN93S