Classic stepper motor buzz WITH A TWIST

Thats a good idea, i just kindof counted them out with a ruler to get it in the right ball park for testing but is there a better way to do it?

I just have standard Marlin

That is the method that I use to calibrate the stepper movement. But I would just put the setting back to default until the motors are working correctly if I were you, to avoid any mistakes as in my case. I think the default setting (on line 440) is: #define DEFAULT_AXIS_STEPS_PER_UNIT {78.7402,78.7402,200.0*8/3,760*1.1}
It might be possible that you misplaced a decimal point while changing the setting, causing the motors to move several times farther and faster than what what they are capable of. Good luck!

Thanks, I went back to the defaults and have been playing with the numbers again with some success. I can usually get the homing smooth but its tough to find numbers that'll work for both homing and regular travel. And even still sometimes they will stall and hum.

If i go to the defaults or anywhere close the motor will whine like its being asked to move way faster then it ever could.

I have lead screws (25mm pitch) on all my axes so it makes it tougher to find suggested values to try

I would use Prusa's calculator to estimate the proper steps_per_unit on your leadscrews and acceleration rates to get you into the ball park, and then fine-tune later when your steppers are working correctly. Hypothesis alert: It seems to me that the problem may still be a hardware one, and that the different firmware settings are just allowing the motors to cope with whatever hardware issue there might be.
However, we seem to have exhausted most of the possible hardware problems earlier in the thread! I'm wondering though; have you tried floating the 5th and 6th pins on your motor?

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Confirmed your wiring:

http://www.sanyo-denki.com/Data/Servo/catalogs/F2_ver1.pdf

If it can spin sometimes, then your coil wiring is correct as well.

I think you may have more of a problem tuning in your A4988 driver. Too little or too much current will make the motors funky.

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"Never argue with stupid people, they will drag you down to their level and then beat you with experience."

Thats right, I've tried the other wiring options but this is the only one where the motors will spin properly even sometimes. And Ive been testing the current every time i make any progress, I've seen what it does and I've found the 'sweet spot' a number of times but it doesn't mean the thing works every time, still seems to kindof do whatever it wants.

I thought it might just be my cheap stepper motors but I wired a better quality stepper up to my printer to test and it doesn't seem to work either. It's slightly larger than my nema 17s what would be some good numbers for federate/acceleration to try on a motor that should work like its new?

I'm having the same trouble as you but the funny thing is that i had it working before then i wrecked the board and bought another on eBay. (it came with a arduino, ramps and all the drivers)
now whether i try an old or new driver it does the exact same thing as you so i dont think it's the driver or motor
i think this guy had the same problem he says he sovled it by rewiring his motors
although i can't help but notice the common denominator is we all bought our stuff on ebay and very recently!

Hey again,

So I've been busy with some things but been tweaking the printer and now I can get it to move quickly, smoothly, and almost every time. However, even with the same federate (but in mm/s instead of mm/min) it acts completely differently and still makes a very loud noise with very little if any net motion in one direction.

I've also noticed that the printer seems to randomly pick the direction it feels like travelling in without much guarantee. And is it strange the the home button makes the printhead move about 10cm then stops it whether it's triggered the endstop or not

I've also swapped out my pololu Aa4988 drivers for some newer better quality DRV8825 and increased my federate to 500mm/s since the motors wouldn't work at all at any lower speeds

For anyone who has this problem:

-I suspect i blew out my old drivers when I just started and didnt know what I was doing
-My new DVR8825 drivers have identical pins except the order of the coils and so you cannot follow the labels printed on the ramps you have to follow the same pattern on the bottom of the driver (i had to switch the 2nd and 4th wires to my connector)
-Also, use your multimeter EVERYWHERE its the only way to see whats going on in the magic world of how this shit works, which is why im more mechanically inclined...problems are visible