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I've been upgrading my Rostock MAX v2 to handle three extruders and a the Polystroooder tri hotend. Part of that is changing the board to an Azteeg X3 Pro. I have everything put together and wired up. I'm talking to the board just fine, and I can heat up the bed and each hotend. However, I cannot get any movement out of any of the stepper motors (see the attached video clip of when I'm attempting to home all axes.). All I get is an alarming wine and a jerk when the software aborts. I've confirmed that the wiring to the motors is correct and each individual stepper driver is good. The firmware should be fine, but I can't think of anything else wrong with the hardware that could cause this kind of a problem. Any ideas on what else I can look at to fix this problem?

[youtube]http://www.youtube.com/watch?v=4Ni0LpbG6rc[/youtube]

Thanks!

By each individual stepper driver is correct, do you mean that each individual driver is in fact capable of driving the motor, and has the current correctly set?

Can you move the carriages with the arms/hotend removed? Will it move downwards when commanded? Have you checked belt tension and cheapskate adjustment? (You may want to upgrade to the IM cheapskates)

If the current is correct, and the other symptoms apply, then it may be you have overloaded the steppers, and they have insufficient torque to produce motion with the additional weight of the Polystroooder hotend. You could attempt to add a sprung counterbalance (those retracting key lanyards might help), Upgrading to higher torque motors, ETC.

If the current is mis-adjusted, then you need to find the current setting which produces motion. I assume that since the X3 lacks built in drivers, that you don't have Digipots. Which means adjusting the pots with a screwdriver, preferablly ceramic, to get it to drive the motor properly.

Attempt a test of the rig with your rambo, but don't bother with the stuff for the hotend yet, as you only need a motion test. If you get movement with the rambo, since I presume it previously worked, then you know it's something related to the Azteeg, and it's drivers, rather than the mechanical issues of the printer.

You might try setting your maximum step rate to a much lower value (I'd suggest 5-10% of whatever it is now), then see what it does. I'm guessing the speed is too high.

Xenocrates wrote:By each individual stepper driver is correct, do you mean that each individual driver is in fact capable of driving the motor, and has the current correctly set?

Yes, that is what I mean. The Azteeg boards have the stepper driver circuitry on a separate breakout board. I have an Azteeg X1 that I use on a Cartesian printer. I swapped out the stepper drivers between the two boards, and same problem. The drivers from the X3 pro worked fine on the X1.

Xenocrates wrote: Can you move the carriages with the arms/hotend removed? Will it move downwards when commanded? Have you checked belt tension and cheapskate adjustment? (You may want to upgrade to the IM cheapskates)

The carriages work fine. I've had this Rostock running for 8 months and about 1500 hours of print time before I started doing this upgrade.

Xenocrates wrote:

If the current is correct, and the other symptoms apply, then it may be you have overloaded the steppers, and they have insufficient torque to produce motion with the additional weight of the Polystroooder hotend. You could attempt to add a sprung counterbalance (those retracting key lanyards might help), Upgrading to higher torque motors, ETC.

I'm putting less than an ounce of additional weight on the effector with the polystroooder. There will be more resistance from the additional wiring and Bowden tubing, but not enough to cause this. I didn't mention it in the OP, but when the motors are powered but not attempting to move they are SOLID. I have to exert a lot of force to get them to move. I doubt that the stepper motors are underpowered.

Xenocrates wrote:

If the current is mis-adjusted, then you need to find the current setting which produces motion. I assume that since the X3 lacks built in drivers, that you don't have Digipots. Which means adjusting the pots with a screwdriver, preferablly ceramic, to get it to drive the motor properly.

Attempt a test of the rig with your rambo, but don't bother with the stuff for the hotend yet, as you only need a motion test. If you get movement with the rambo, since I presume it previously worked, then you know it's something related to the Azteeg, and it's drivers, rather than the mechanical issues of the printer.

The drivers work fine on a different printer with an Azteeg X1. You can make the case that the steppers are from a different manufacturer, and they are, but both printers use NEMA 17 steppers, and they are rated for about the same amount of torque. There isn't all that much difference between them.

Earthbound wrote:You might try setting your maximum step rate to a much lower value (I'd suggest 5-10% of whatever it is now), then see what it does. I'm guessing the speed is too high.

I'll check this when I get home tonight. Thanks for the suggestion.

Stepper current can be incredibly finicky on those driver boards, like a difference of an 8th of a turn can stop them working. I'd try messing with the current a bit and see if it works, you can set them with a meter (for which you need a metal bladed screw driver and 3 hands) but I usually just turn them up until they stop working then back off a small ammount. There can be a pretty big difference between Nema 17 motors and the required/acceptable current.