Issue measuring VREF a4988 Steppers

[Gopher_By_Fende]

Hi All

I recently acquired a second hand Geeetech i3 which I'm currently trying to get back into proper working order. I've been trying to set up the a4988 steppers correctly, however whenever I try to measure the VREF (one probe on the PSU earth, one on the steppers pot) I am only getting readings of around 0.05v, when I would be expecting 0.5v even on the low side. The odd thing is that the motors all do work, it will print, just a poor quality. This is happening across all the steppers, including one which I have just bought as a replacement for a bust X-Axis one (It was a cheap one from Amazon)

Has anyone come across this, and any thoughts as to what is going on, as I can only either think that my meter is knackered (though it works fine measuring the 12v output on the PSU) or the steppers Pots are some how just for display and I can't measure or adjust the voltage

Thanks

Goph

 

[bulb66]

Hi All

I recently acquired a second hand Geeetech i3 which I'm currently trying to get back into proper working order. I've been trying to set up the a4988 steppers correctly, however whenever I try to measure the VREF (one probe on the PSU earth, one on the steppers pot) I am only getting readings of around 0.05v, when I would be expecting 0.5v even on the low side. The odd thing is that the motors all do work, it will print, just a poor quality. This is happening across all the steppers, including one which I have just bought as a replacement for a bust X-Axis one (It was a cheap one from Amazon)

Has anyone come across this, and any thoughts as to what is going on, as I can only either think that my meter is knackered (though it works fine measuring the 12v output on the PSU) or the steppers Pots are some how just for display and I can't measure or adjust the voltage

Thanks

Goph

Do you mean the PSU Ground? What resolution do you have the meter on?