Stepper and hot end stop mid-print

Hello,

I have a problem on my Rostock with ramps. It was printing fine but I wanted to change the end effector (the platform) and since my print are stopping mid-print.

The symptoms are :
Stepper are disable (I can move the paltform by hand).
The hotend is not heating anymore.
The heatbed is fine.
The commands are sent form repetier to the printer
On the LCD everything keeps updating (position, temp, fan speed, ETA) as if the print was going on.
If I turn the printer off (unplug usb and switch the atx off) and restart, The stepper control are back (can home the printer)

I have tried printing form SD-Card and throug USB, exact same problem

I have tried Gcode from slic3r and cura

I didn't saw any message error from repetier, everything keeps going as if the print was normal, it seems like I juste have no more power to the stepper and the hot end

Feel free to ask any information or test if you think it can help troubleshooting .

Stepperdriver failure from overtemp protection is my first guess. Do you have a fan blowing on the Ramps?

Yes I have.

If I understand correctly the overtemp protection, the print should go on after a while waiting, and the hot end would still be heating. Am I wrong ?

So no one as any idea of what is going on here ?

My guess is that there is a failure in the stepper+hotend power circuit, but where this failure come from, ramps ? PSU ? Don't know what to do to troubleshoot so any help would be great.

Edited 1 time(s). Last edit at 03/14/2016 03:52AM by Repier37.

I had a freeze that would not resume caused by overheated stepper drivers

Try feeling the heat sink on each driver when it freezes, if one is noticeably warmer try turn down the voltage on it