Extruder driver and 55V step-up
When the extruder motor stops or skips, the cause is usually mechanical — something stuck in the extruder. It can also be electrical: the stepper driver not delivering current, because the step-up (boost) converter that feeds it has failed.
Background
Section titled “Background”The main extruder stepper is driven at a boosted voltage of ~55V (higher than the 24V bus) to give the screw enough torque. A small step-up converter produces this 55V and feeds the extruder stepper driver.
Symptoms of a failed step-up
Section titled “Symptoms of a failed step-up”- The motor skips now and then at high flow, then later stops turning altogether
- The step-up converter’s output is not ~55V on a multimeter
- It may show visible sparking or scorching
A failed converter starves the driver, so the motor gets no current.
Diagnosis order
Section titled “Diagnosis order”- Rule out mechanical first — with the printer off, check for material jammed at the screw entrance; a stalled screw is the first thing to rule out when the motor “stops”. See Extruder motor skipping and the feeding-zone clog.
- Check flow isn’t simply too high — sustained very high flow can make the motor lose steps; reduce flow / add SmoothFlow, and verify temperatures so the melt isn’t too stiff.
- Check the motor connector — a fried or loose connector is the first electrical cause to check. Look for burn marks; re-seat at both ends.
- Measure the 55V step-up output with a multimeter. If it does not read ~55V (or shows arcing/sparking/scorching), the converter has failed — contact Ginger Additive support.
- The DM860T driver — if 55V is present and the connector is sound but the motor stays silent, the driver itself has failed.