Everything freezes up

Hey guys, so I am attempting to build a Prusa Mendel. I purchased and assembled a RAMPS kit from Ultimachine. I am completely new to the whole electronics/programming thing. I installed the firmware from [github.com] to my arduino and then attached the RAMPS board. After that, I powered everything up. As soon as I flicked the power switch on all of the motors tensed up and could no longer be turned by hand, the heat sinks on my Pololus also got warm. While it was like this, I quickly tried to test the x-axis by going into the reprap printing program and it didn't budge. I quickly shut the whole thing off. Any clue what I did wrong?

You made a good decision to power everything off. Each Pololu board has a trimpot that needs to be properly adjusted or your motors won't turn (not dangerous) or the Allegro chip would overheat (dangerous). Most firmware is set to hold the x and y axis but not the z axis. So, you won't be able to move them as soon as you power up as you found out.

The fact that you couldn't nudge them with the Reprap host might be a communication setting issue. You might not have the correct USB device selected or the firmware that you loaded might have set the baud rate to a different setting from what the host is set for. It could also be an incompatibility with the version of the reprap host that you're using and the firmware.

I suggest you load Sprinter instead (https://github.com/kliment/Sprinter). That works for a lot of people with RAMPS. It's compatible with Repsnapper and also with Kliment's Printrun (https://github.com/kliment/Printrun) for sending g-codes to printer. Save the trouble and skip the Reprap host all together. The other sw you will need is the latest version of Skeinforge, which is currently 41.

Though I have a Gen6 board, the 'hold'ing of the motor spindles on power up is normal. This stops the axis being knocked and messing up positioning. It also happens to use a lot of power, so yes, your driver chips will get warm. The axis will not move (at least they don't on Gen6) if you don't have the axis limit switches (optos or microswitches) attached. The Z axis is usually not held.

brnrd-I downloaded Sprinter, Repsnapper, and Skeinforge.
For some reason I can't seem to open Skeinforge. After downloading Skeinforge I used WinRAR to extract the files into "Program Files". There doesn't seem to be any files that I can open. Here's a screenshot of the Skeinforge folder
[imageshack.us]


I attempted to upload the Sprinter to my arduino, and below is the error that came up on the Arduino software

Binary sketch size: 31560 bytes (of a 258048 byte maximum)
avrdude: stk500v2_getsync(): can't communicate with device: resp=0x01
avrdude: stk500v2_command(): unknown status 0xc8
avrdude: initialization failed, rc=-1
Double check connections and try again, or use -F to override
this check.

avrdude: stk500v2_command(): unknown status 0x01
avrdude: stk500v2_disable(): failed to leave programming mode

Since I'm a software noob I have no clue what's going wrong. One thing strange is that the Arduino software says its using COM3 for the serial port. I have the board plugged into my laptop's USB not a serial port...

Thanks for the responses

You'll need to install Python to run the Skeinforge.py application. Download and install Active Python and you should be good to go.

JB

---

--
Check out my blog: AdventuresIn3-DPrinting

The Arduino boards use a USB to Serial interface layer. If you have not already done so, you need to install the drivers for your particular arduino. These drivers are included when you download the Arduino IDE. You can check the device manger (if using Windows) to see if the Arduino MEGA is listed under Unknown or Ports.

The Arduino MEGA currently comes in two flavors. The original (which I prefer) MEGA 1280, and the new and "improved" MEGA 2650. The 1280 uses an FTDI USB to Serial chip. The 2650 uses an Atmel microprocessor running a USB to Serial emulation. This both reduces the cost of manufacturing, and allows one to re-program the chip to do other things, like joystick emulation (nothing to do with RepRap and RAMPS).

To troubleshoot your problem, begin by attempting to connect to the Arduino without the RAMPS attached. Grab a fresh copy of Sprinter, or whichever firmware you prefer, and load it up in the Arduino IDE. The IDE needs to be configured for the board type, and COM port that you are using. Once you have done this, try uploading the firmware to the Arduino. It should just work, but I'm speaking only from my experience with Sprinter. Your mileage may vary if using something else.

Once you have determined that the firmware has in fact loaded. Add the RAMPS (make sure to disconnect all power), and connect everything back up.

I solved this problem by editing the following code like the comments say:

// uncomment one of the following lines for RAMPS v1.3 or v1.0, comment both for v1.2 or 1.1
#define RAMPS_V_1_3
// #define RAMPS_V_1_0

This should correct the pin assignments issue in the firmware.