Having a problem is driving 2 Z motors?

Hello out there!

I am having some real difficulties driving 2 "Z" motors on my upgraded "mendelmax-ish" 3d printer. The motors seem to be under powered and do not move. I have built similar machines and they all print just fine. This one has me a bit perplexed. There is no weight that the motors are caring, just 4 V-Wheels and an aluminum plate.

What I have attempted so far.

Hooked it up to a new RAMPS board = same problem
Hooked up new microsteppers = same problem
Hooked up new motors = same problem
Turned up trimpot = same problem
Changed e-stops= same problem just more noise
+ When running 1 motor it works just fine
++ When 2 motors are not attached to the coupler it works just fine


The setup is as follows:

RAMPS 1.4 w/ A4988? microstepper driver
Marlin firmware
3/8" Acme rod (Heat-Treated 4140 Alloy Steel)
Dumpster CNC 3/8 anti backlash nut + coupler
Power Supply 400W 12V 33A
Nema 17 Stepper Motor 59Ncm(84oz.in) 2A
Vwheel+ Vrail from inventables

Any help would be greatly appreciated.

Thanks

Are your motors hooked up in series, parallel, or separately with independent drivers (using E1 for the second z-axis motor)?

They are running in parallel—I think.

To clarify, is this "Z" diagram in series?

[reprap.org]

And this "Z" diagram parallel?

[forums.reprap.org]

I also have to keep E1 open for a second extruder.

Quote
coreformula
They are running in parallel—I think.

To clarify, is this "Z" diagram in series?

[reprap.org]

And this "Z" diagram parallel?

[forums.reprap.org]

I also have to keep E1 open for a second extruder.

Both those diagrams show them in Parallel

The first diagram you can't tell. It would depend on how the adapter breaks out the individual connections. But it probably is parallel. The second is just using both z-axis headers which is parallel.

Running the steppers in parallel requires 2x the current from the driver, so your drivers may not be able to power them at full power. A4988-based drivers like stepsticks and pololus top out at 2A with active cooling (less with passive) before they overheat. You may need to switch drivers or rewire for series.

Quote
coreformula
They are running in parallel—I think.

To clarify, is this "Z" diagram in series?

[reprap.org]

And this "Z" diagram parallel?

[forums.reprap.org]

I also have to keep E1 open for a second extruder.

To wire them in series (Reduces the total current required) see Z Axis series wiring

HTH

Doug

I now have it running in series. It is a bit better. Runs smooth when controlling from a computer, but still skips especially when controlling the bot with the LDC controller (http://reprap.org/wiki/RepRapDiscount_Smart_Controller)

I am also a bit concerned when it comes to adjusting the trim pots on the microstepper. Is there any way that could be contributing to the problem?

Also, not sure how much this matters, but my "Z" estops are 1588