Not a N00b Question…and yet.
IGentUS is making initial attempts at movement, at least in X and Y directions. It’s using an AtMega + RAMPS 1.4 shield as a brain, with DRV8825 drivers. 1/16 stepping.
If I chop out the thermal parts of the gcode, it starts moving as youd expect, but very soon, the drivers start to hit thermal cut-out modes. (Movement happens in steps, with lots of halting.)
The itty Bitty Heat Sinks don’t do much, and a non-contact thermometer is showing 175F+…I’m not sure how to set the reference voltage, and google isn’t being very helpful. The heatsinks also didn’t come with glue, so the thermal transfer is FAR from ideal…and yet the delta, with passive cooling never ran into issues like this.
I’ve got both the 5 and 11 amp feeds plugged in, from a 40 amp PSU, and there’s no extruder or bed heater in the equation yet.
There are small, surface mount potentiometers on each driver module. Adjust them slowly (and gently, they can break) with a plastic-tip screwdriver (to avoid shorts) as the steppers are moving (maybe load a calibration cube?). Generally CCW for lower current, and CW for higher (you seem to be looking for lower).
yeah, my ceramic screwdriver died, if I use a metal one very very carefully, I start to hear the local AM radio station(!).
Input into the RAMPS has been measured at 12V, and everything else appears to be functioning okay.
Cool, I’ll pick up a non-conducting screwdriver tomorrow (and some thermal grease/glue) and tune some more. I turned it down to what appeared to be the lowest setting, and pointed a 12v DC fan at the RAMPS and it was much happier, and pulling the fan away I could get it into thermal fault and then back in to normal operation…I also have everything WAY cranked up, I doubt it could lay down filament at these speeds.
How did you kill a ceramic screwdriver?
@Brian_Wilson well, it’s no longer a flathead. They’re noconductive, but they’re brittle!
For me, the DRV8825 packed quite a punch - it managed to get the motor hot enough to warp a motor mount without a heatsink in the driver, while A4988 drivers never managed to do that even with a heatsink, thermal epoxy and a fan. That being said, I went back to A4988s because the DRV8825 were super noisy for me, but I believe Pololu has since changed the driver’s board to fix that.
As far as screwdrivers go, there’s nothing wrong with using a metal one. Just preferably use one with a plastic grip.
There’ll definitely be some thermal design on the new printer. On an up note, XY is faster that I’ll EVER be able to lay plastic down with, and the Bowden will be a much smoother curve than I could ever get on the delta. To borrow a real estate term, this printer’s got good bones.
I do it differently: I do use a metal screwdriver. I connect my voltmeter black wire to GND and red wire to the metal part of the screwdriver. This way I can read the voltage on the pot while adjusting it. Make sure it is around 0.8V (that would be 1A).
It was voltage. Instead of jerry-rigging a volt-meter to the screwdriver, I’d measure, adjust, measure, adjust. Got it to .75 and .8 for X and Y and it’s cooling find with passive cooling. Now…lifting 6 Lbs of Bed? That may take a little more oomph.
@Mike_Miller Back of the envelope calculation: you’ll need some reduction to get it to lift reliably 6 pounds with a belt. Assuming your pulley radius is 1cm and your motor is 4.8kg•cm@1.6A that will give you just 3kg@1A(just 6 pounds) and you want to have some safety margin. As 8825 can give you up to 1.5A without cooling fan (approx) you may want to give Z-axis some extra juice, like 1.2V. (measuring while turning the pot is better done if you have three hands or one of these http://www.dhgate.com/product/p1021b-clip-testing-lead-wire-testing-lead/141758935.html )
@Miguel_Sanchez I missed the (100 pieces in lot) designation and was wondering what magix cables cost $200 a set! 
There’s two directions I can go in at this point. The bulk of the weight is in the glass build plate, the RAMPS handles two motors in Z by design, but neither handle the loss of power to Z crash potential. Still noodling that one. If I go counterweight, I’ll need to nail down the base weight I wan’t to counteract as there’d be a huge disparity between aluminum plate + gekkotek only and plate + cork + heater + glass + gekkotek.
I noticed the price after posting it, yeah, just use the picture 
One or two motors is not going to make a difference unless you use one Pololu to power one Z- motor (if you have two Z-motor you can power each one with a single Pololu provided you do not want to go dual extruder with RAMPS). That will double your carrying power on Z.
However, a single geared motor can do the job too with the added benefit of increased z resolution and the bed not falling down in the absence of power.