HMS 0300-0600-0001-0003: Motor-A resistance abnormal
LayerWalker is a participant in the Amazon Services LLC Associates Program. We may earn a commission when you buy through links on our site, at no extra cost to you.
The driver measured Motor-A outside its expected resistance band. That is a broader complaint than a dead short: a partly broken lead, a crimp backing out of its housing and a genuinely failing winding all land here.
Affected machines: A1, A2L, P2S, X1 series.
Where to buy
Why intermittent is the usual pattern
A dead short gives a consistent fault. An out-of-range resistance usually does not, because the common causes are mechanical: a strand that separates when the cable chain bends one way, or a crimp that makes contact until the head accelerates. That is why this code often appears mid-print and then clears on a restart.
Chasing an intermittent fault with a meter means moving the thing while you measure, not measuring it at rest.
Intermittent fault, sometimes clearing on restart, sometimes halting a print part-way through
Crimp backed out of the connector, partly broken lead in the cable chain, or a failing winding
- Power off at the wall and unplug Motor-A at the board.
- Measure each coil pair. Note both readings; the two coils should be close to each other as well as within range.
- Flex the cable gently along its length while watching the meter. A reading that jumps is a broken strand.
- Pull lightly on each wire at the connector housing. A crimp that has backed out looks seated and reads open.
- If readings are steady and matched, swap connectors with Motor-B to decide between harness and driver.
Our page on 3D printer stepper motors covers how to tell a dead motor from a dead driver, which is the distinction this code turns on. The troubleshooting index covers where motion faults sit among the rest.
FAQ
Can I swap motors between axes to test? On a CoreXY the two motors are usually identical, which makes that the fastest test you can run.
Do stepper motors fail often? Rarely. Wiring and connectors fail far more often, which is why the meter comes before the credit card.
Is it safe to keep printing? No. A motion fault mid-print wastes the whole job and can drive the head into the part.
What resistance should a coil read? Typically a low value between about 1 and 5 ohm. Compare the two coils against each other.
LayerWalker
Print defect diagnosis, calibration procedures and parts that actually fit. Corrections welcome through the contact page.
