Stepper driver modules failed on extruder

Hi guys,

I just got a printer going with a new RAMPS board, but I have had 2 A4988 modules fail on the extruder motor.

I had a heatsink on the first time, and added a fan before the second failed.

The first one failed on the a thin wall calibration print, then after replacing it I got a few prints done OK. Then it failed again on a thin wall calibration print. The motor vibrates and turns erratically even with nothing attached.

The motor was only getting slightly warm when it was working, the coils both measure 2 Ohm, and the Y axis connection drives the motor just fine.

Is there anything I should check with the wiring or extruder setup?

I had thought that even a completely stalled motor should be OK at around the 1A setting?

I just had the exact same thing happen...
Still searching for the culprit.

My current/voltage was good, no over heating was happening.

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Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold

Did you put one of the "failed " Pololus back in to try again?

No, I didn't bother following through with testing on the second blown pololu,
as it showed the exact same signs of failure as the first one.

I'm thinking it maybe power spikes from plugging the 12v power in/out?

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--------------------------------------------------------
Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold

I cycle my 12v plugs quite often so I would doubt its that. Have you tried the "blown" Pololus with the X or Y motor connector plugged into the extruder socket on the ramps board?

I think we had similar things happen once (also with the extruder motor). Turned out to be a loose contact somewhere in the wiring IIRC.

Well, listening you you guys has paid off.
Seems its not the driver after all...

When running gcode, everything runs just fine!!
No overheating, all power/steps/temps are correct.
holding torque is good and strong.

As soon as I run gcode, it seems ALL axis are getting a 'stepping'
signal of some sort...when one axis is issued a step command
(hope that makes sense?)
and all power to the steppers are at a minimal level(I can easily push the x or y axis)

Still looking into my connections, all seems good.
I'll keep you posted.

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--------------------------------------------------------
Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold

I made a small video of whats happening...
Donno why its doing this, ran perfectly the day before.

[www.youtube.com]

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--------------------------------------------------------
Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold