<p>Does the switch work? You should raise the X-Z gantry and home the machine, Z will home last. When it goes down press the switch, it should stop.</p>
<p>If not, then you might have a broken endstop switch, cable or it might be incorrectly inserted (causing a short circuit). The worst case would be a broken controller board. I don't expect the firmware to be incorrectly configured in this case.</p>
<p>If you have a multimeter, you could even test if there is a signal, when not pressed, the multimeter should read 5 V, when pressed, no voltage. This is a safety measure.</p>
<p>Normally if the endstop or cable is broken, no voltage is read by the controller, and the printer will not go down (negative Z direction) to protect the printer. In case the Z axis keeps lowering while pressing the switch, you could conclude that the switch is not working and keeps returning a voltage value high enough to not warn the controller board that the printer should stop.</p>

CC BY-SA 4.0
2024-07-02T21:15:43.893Z
2024-07-02T21:15:43.893Z
0scar
<p>I recently bought a BIQU B1 as my first 3D printer and the assembly process went just fine.</p>
<p>When I tried homing the Z axis, it reached the limiter/stop micro switch and it just keeps trying to go lower, and making the nozzle jam into the bed.</p>

CC BY-SA 4.0
2024-07-02T21:14:15.033Z
Have you checked that the micro switch works, with a multimeter? Have you checked the wiring and connections to the main board? Without wishing to state the obvious, it sounds like the switch isn't being registered by the board (for whatever reason). If you have checked the wiring and switch with a meter, then the next step would be to check the board itself, in particular the pins for the Z axis switch. Try shorting the pins (assuming that the switch shorts when closed/pressed) manually to see if the nozzle stops moving, during the home process.
Greenonline
<troubleshooting><endstop>
BIQU B1 ignores Z limit switch when homing
Clown101
# BIQU B1 ignores Z limit switch when homing

(Asked by: username_0 on 2024-07-02)

I recently bought a BIQU B1 as my first 3D printer and the assembly process went just fine.

When I tried homing the Z axis, it reached the limiter/stop micro switch and it just keeps trying to go lower, and making the nozzle jam into the bed.

**Tags:** troubleshooting, endstop

> **Comments:**
> **username_1**: Have you checked that the micro switch works, with a multimeter? Have you checked the wiring and connections to the main board? Without wishing to state the obvious, it sounds like the switch isn't being registered by the board (for whatever reason). If you have checked the wiring and switch with a meter, then the next step would be to check the board itself, in particular the pins for the Z axis switch. Try shorting the pins (assuming that the switch shorts when closed/pressed) manually to see if the nozzle stops moving, during the home process.  

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## 1 answers

### Answer by username_2 on 2024-07-02. Score: 1

Does the switch work? You should raise the X-Z gantry and home the machine, Z will home last. When it goes down press the switch, it should stop.

If not, then you might have a broken endstop switch, cable or it might be incorrectly inserted (causing a short circuit). The worst case would be a broken controller board. I don't expect the firmware to be incorrectly configured in this case.

If you have a multimeter, you could even test if there is a signal, when not pressed, the multimeter should read 5 V, when pressed, no voltage. This is a safety measure.

Normally if the endstop or cable is broken, no voltage is read by the controller, and the printer will not go down (negative Z direction) to protect the printer. In case the Z axis keeps lowering while pressing the switch, you could conclude that the switch is not working and keeps returning a voltage value high enough to not warn the controller board that the printer should stop.


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