Motor flickering

Hi there.
I am new at RepRap so I apologize in advance if I make few mistakes.

The problem is that is me and my friends build a 3D printer / CNC router but we have a problem with motors flickering.
To explaint better I made a video and from 1.11 you can see the problem.
https://www.youtube.com/watch?v=3B07D6gLGdQ

The flickering starts on it's own randomly on home position, center or any other.

SETUP:
Initially it was meant to be a Mendel Max 2 but it is much bigger
The motors are NEMA 17
On RAMPS v1.4 is uploaded firmware Marlin 1.1.0-RC7
There are two power units.
2x 12V 600W computer power units make a 24V power supply for the motors and and logic
1x 25A 24V is for the heaters
The power units and ramps are in a different box and well ventilated.

We checked and double checked the wiring, power units, move motors without the belt, change axis connections but the problem persist.

Has anyone any idea what it could be?

Did you check your endstop switches?

it may be possible the steppers are too weak to drive the load or the current needs adjusting

Yes the endstops work fine, but as I said the flickering can happen in the center position as well so I don't think it has anything to do with the end stops.

The steppers are not to weak because the problem persist even if we remove the belt and they are free.

Edited 1 time(s). Last edit at 10/18/2016 05:50AM by i23D.

I didn't mean if the end stops are triggering when you hit them to stop moving I meant do they possibly have a loose connection.
Aside from that it looks like you are missing steps. How have you connected the stepper motors drive shaft?

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Out of the box thinking is easier when you never fitted in the box to begin with.

Sounds like the stepper driver is turning off and on due to overheating.

Hi.
We have found the problem and you were right
One colleague adjusted the current on 250 for some testing without telling anyone and didn't put it back.
Thank you very much.