Extruder seems to be out - Test procedure [solved]

Hi,

I am using a Mini for a while with colorFabb products with great joy. The Mini does not suffer any modification since it has been bought around 8 months ago and it was working like a charm.
The printer is not printing everyday and everyday long but I use it 2-3 times a week (it’s an average).
I use OctoPrint on a Raspberry in order to get tethered.

Today, I switched from PLA/PHA to nGen and extruded manually and then using software in order to get a clear extrusion. I then started my print which suffered a jam.
I switched off and disconnected everything and unmount the toolhead in order to remove the jam.

When everything when back mounted, everything seemed to work fine (heater cartridge, extruder temp, fan, Y axis) except that the extrusion is not moving at all. Wires are not disconnected and are not stressed out. Wheels can move when pushing by hand.

I suspect that NEMA driver on the Rambo is dead.

Does anybody have a test procedure?

The only way i know to truly test if the motor is bad is to open up the electronics box and switch the stepper motor onto another port and test it using cura or octoprint manual movement settings.

Are you sure the motor is not turning or making sound? Have you checked that the small heringbone gear is not loose and spinning freely?

SHAME ON ME!!!

The problem was simply due to a cold extrusion which is prevented!