Power Help Please

Okay, so I'm totally new to 3d printing and my only background is in programming. Answers will definitely need to be "like I'm 5"...

So I finished putting together a Prusa from MakerFarm, [www.makerfarm.com], using the prebuilt RAMPS 1.4 kit. I am powering it with the USB connection and one these 12v 30a power supplys:
[www.newegg.com]

Loaded it with the Sprinter firmware and can successfully connect to it with Pronterface, but that is where the success ends. Nothing moves, no humming, nothing at all.

So far my troubleshooting has consisted of:
Tested the terminals from the power supply and they are giving 12v.
Removed all motor/hot ends/thermistor connections one at a time, no change.
Removed everything leaving ONLY the X-axis motor connected, no change.

Here is the console output from Pronterface:
Connecting...
Sprinter
1.3.22T / 20.08.2012
start
Printer is now online.
SD Start
SD init fail
Soft PWM Init
Planner Init
Stepper Timer init
Free Ram: 4158
Plan Buffer Size:1152 / 16

So - where do I go from here? I'm guessing the power supply is the issue, but I'm not sure where to start looking for issues. Open to any ideas. Let me know if I should post any pictures or additional information. Thanks!

Before using Sprinter, I would give the RAMPS test firmware a go. You can download it here. Install it like you did Sprinter (open in Arduino and then upload it to the board).

The test firmware will move your motors back and fourth without instruction from the computer, and without regard to endstop status.

If this works, then you know your electronics is good, and you are dealing with a software issue (if the thermistor isn't hooked up, if the computer can't tell the steppers to move, if the steppers think they're at an endstop, then things wont work with the actual firmware because of built in protections).

I don't think it would be your power supply if you are able to get 12v out of it.

Remember to always remove power from the board BEFORE removing the stepper motors or drivers. You can easily cook your driver by unplugging a powered stepper.

Thanks for the tips.I will definitely try the RAMPtest firmware. I have a follow up question about the orientation of the stepper motors. The stepper motors came with molex connections pre attached. I am following the standard ramps wiring diagram [reprap.org] , but I'm worried I'm misunderstanding the orientation. The connectors show a 1 and 4 giving the wires these assignments:

1 = red
2 = green
3 = yelllow
4 = blue

The stepper pins are labeled 2b, 2a, 1a, 1b, to me this means:

1 red = 2b
2 green = 2a
3 yellow =1a
4 blue = 1b

Is that correct?

Edited 1 time(s). Last edit at 03/21/2013 10:09PM by aaroninaustin.

If you plug them in the wrong way round, no harm will be done- they will just go in the wrong direction. Generally, the red wire end of all the motor plugs should be nearest the left (power inputs end of ramps board). I noticed your boot screen shows it trying to enable SD support which I assume you haven't got (SD board attached). I wonder whether this is holding things up? You should disable it in Sprinter if you don't have it.

I also put together a Prusa i3 and I think you may be using an inadequate power supply. I started out with a generic 400W ATX power supply which worked ok except that it could not heat both the bed and nozzle enough for ABS, even though it claimed to provide 20A on the +12V rail.

I don't think that 360W power supply you linked to would work even if it worked according to spec.

I bit the bullet and got a $50 Antec Basiq 500W power supply from Fry's. Now my heating is working and not taking 30 minutes.