I was doing some calibrations, wherein I would start a print, reset, start a print, reset, repeat. Just as I was finishing, the stepper driver for the extruder failed. It now only extrudes in one direction. It works if I swap drivers. Re-seating the failing driver doesn’t fix it.
I thought the extruder would have the smallest load, so I am surprised it failed first.
This is a ramps 1.4 kit from makerfarm which came along with the prusa i3 kit. The drivers came pre-installed in their “optimal” current setting according to makerfarm and I have not adjusted them.
Do you think this is a fluke?
Should I buy more than one driver in anticipation of future failure?
I think it’s a fluke. It’s hard for me to come up with a damage path that would lead to a stepper only going in one direction. (I’d check the solder joints on the direction pin on the chip.) If it’s going to fail from an over-current (which it shouldn’t: it should have an overtemp cutoff, or at least all the chips WE make have overtemp cutoffs) it wouldn’t drive at all, or wouldn’t spin, just hold and buzz (depending if it burnt out the entire bridge or just half of it.) As such, I doubt it was the motor and conditions that did this.
@Thomas_Sanladerer , possibly. There is a big fan on it but it has not always been there. Maybe there’s a bubble caught under the heatsink.
@Mike_Miller , are you thinking I should check the traces on the polulu board itself? I think that swapping drivers should have ruled issues on the ramp board or in software. I suppose the header could be making bad contact as well.
I suspect a situation like @Mike_Miller describes: there’s something dead outside the chip, controlling the step pin, so now it’s never getting a signal to reverse.