Having a problem with driving extruder motor-driver.
It seems that there is a design fault on the RAMPS 1.6 board and schematic.
|RST and |SLP pins are connected together, but not to anything else. These pins are therefore floating. On my particular bpoard, those pins on the 3 axes ARE pulled HIGH.
[github.com]
Looking further, Typical circuit for the A4988 has 5k pullup on SLP.

Edited 1 time(s). Last edit at 07/29/2026 11:02AM by sbkenn.

Remove your stepper drivers and retest.

A4988's module, for example, has a built-in pull-up on the sleep pin



Edited 1 time(s). Last edit at 07/29/2026 10:35AM by Dust.

Thanks.
2 of my 10 modules are faulty. I accidently ordered 2 packs of 5. RST/SLP are floating at about 1.3V