Just run it, that code just moves motors and flashes lights, it reports the temperatures over the serial link but doesn't care what those temperature readings are. Without the bed thermistor, it'll just report 0C.by Andrew Smith - Reprappers
Which firmware are you using, and can you post your configuration?by Andrew Smith - General
You should be able to measure vref directly off the pot wiper, which should be much easier and more precise than trying to figure out the angles.by Andrew Smith - Reprappers
Set motherboard to 3 for RAMPS 1.2by Andrew Smith - General
It never is one size fits all, but the current normal setup of a tiny drive wheel is probably sub-optimal. If the extruder can tear through the filament without stalling the motor, then we have torque we could be using to extrude faster or push through jams that would stall existing extruders. If the motor stalls before stripping the filament, then we know that we can use all the torque the motorby Andrew Smith - General
Skeinforge has some 2d functions. It can't take dxf files, not sure on hpgl. Beyond that, you might want to look at how people generate gcode for milling pcbs.by Andrew Smith - General
You can set the home retract distance in configuration_adv.h , but there's no option for home retract speed.by Andrew Smith - Reprappers
Sounds like your stepper drivers are set to full step mode rather than microstepping. I'm not sure what electronics you have, but there should be some jumper headers to set microstepping, for x16 you typically need jumpers in all three positions.by Andrew Smith - Reprappers
It should be as simple as adjusting the homing feedrate, which is on line 479 of configuration.h in current Marlin.by Andrew Smith - Reprappers
Vref can only vary between 0 and 3.3V on that stepper driver, it sounds like you're measuring the test point that gives the motor supply voltage - the one you want is on the other side of the board, although the voltage can be measured from the trimpot wiper itself.by Andrew Smith - Reprappers
Skipped steps. Check for mechanical problems, make sure the carriage moves freely along the axis, and try a little more current to the motor.by Andrew Smith - Reprappers
You nudge the head in pronterface till it's roughly at the low end of X and Y, and spend a bit more time positioning it on Z. Since Z rarely moves by hand on most machines, this isn't as much hassle as it sounds, just have your end.gcode position the head at a known level at the top and your start .gcode uses G92 to restore that Z coordinate when the next print starts.by Andrew Smith - General
Acceleration, here, means ramping the motors to the desired speed rather than asking them to change speed within a single step.by Andrew Smith - Printing
Most of configuration.h is easy enough to figure out, but some tutorials on C may help if you have problems understanding the language. When you change the firmware, you need to recompile and re-upload the firmware. For this specific change, you need to alter line 310 assuming you have the most recent marlin. If you didn't compile your current firmware be aware that theres no way to pull your exby Andrew Smith - Reprappers
Looks like the print got too hot, which is a big problem with small prints. Your slicer will have a solution, in skeinforge you activate the 'cool' module to slow down the print on small layers and give it time to cool, I don't know how other software handles this.by Andrew Smith - Printing
Turn up the voltage, The a4988 is a chopper driver and will limit the current provided to the motors, so you can exceed the rated voltage without damaging the motors.by Andrew Smith - General
Its probably the polyfuses on the RAMPS, you can bypass them with a length of wire (provide suitable overcurrent protection elsewhere), or it might be enough to point a fan at them to keep them from getting hot enough to trip.by Andrew Smith - Printing
Could be a dry solder joint, rework it and see if the problem clears up.by Andrew Smith - RAMPS Electronics
Also, the regulator isn't well cooled on Arduino, and the RAMPS prevents air movement around it, so I wouldn't go anywhere near its rating. The regulator on the official Mega 2560 should be able to handle 14.5V though.by Andrew Smith - RAMPS Electronics
Pronterface doesn't care what settings you have, it simply sends the gcode you give it to send. So, you need to get slic3r to generate gcode with the correct temperatures. No idea how you do that, check the slic3r manual or wait for someone who uses slic3r to come along.by Andrew Smith - Reprappers
You're talking about diode D1, its under the X and Y stepper driver sockets and is indicated on the silkscreen, along with its orientation. You can find assembly instructions for RAMPS on the reprap wiki if you need more information.by Andrew Smith - RAMPS Electronics
Get the arduino IDE, and get a copy of the firmware of your choice. Marlin is good. Or sprinter. I hear good things about Repetier as well. Open the firmware in the IDE, work through configuration.h to set it up for your printer, select 'arduino mega 2560' in the board option under the tools menu, and press the upload button.by Andrew Smith - Reprappers
The lines starting in // are comments rather that code, so two of the three settings are just there to suggest possible useful values. The only actual PID settings are the ones under //Ceramic Chess Hotend, so change those.by Andrew Smith - Reprappers
This is almost always due to incorrect endstop logic, change the MIN_ENDSTOP_INVERTING lines to fix it. You can use M119 to see what the endstops are reporting, so check that they are changing state when triggered,by Andrew Smith - Reprappers
If you look at the traces, each set of pins is connected identically, so you can use either socket, or plug a motor to each socket rather than splitting the wires later.by Andrew Smith - Reprappers
Put the last set in firmware, each cycle of autotuning should improve on the last. Marlin doesn't, IIRC, use PID for the heatbed since its response is much slower and temperature fluctuations less of a problem, so bang-bang control is sufficient.by Andrew Smith - Reprappers
PLA is hard to print because of the very low glass transition temperature. You need to keep the top of the hotend below 58C or it will jam). You need to duct the airflow from that fan so that it only cools the heatsink part of the hotend.by Andrew Smith - General
One uploaded, it'll go straight into the test loop. Motors should move, output LEDs should flash.by Andrew Smith - RAMPS Electronics
Try installing FTDI drivers from here:by Andrew Smith - Reprappers
Thermocouples do not measure temperature directly, but the difference between the cold junction and the hot junction. To make a practical temperature sensor, you need to know the cold junction temperature. The ice water is a crude way of doing fixing that temperature at 0C, but the MAX6675 and similar chips use a thermistor to monitor the cold junction temperature and thus determine the absoluteby Andrew Smith - General