Skip to content
FarmLoop Help Center

Verify installation, Bambu A1 Mini and A1

This is the A-series side of the verify-installation step. Applies to both the A1 Mini and the A1 — the board and the self-test sequence are identical.

What you do

Section titled “What you do”
  1. Plug the AMS power cable back into the printer (this supplies power to the FarmLoop board), or connect USB-C from a computer.
  2. The board powers on and automatically cycles through each component:
    • Fan spins for a second
    • Linear actuator extends and retracts once
    • Limit switch is queried
  3. Watch the LED startup sequence — it confirms each stage of the boot.

Expected LED pattern

Section titled “Expected LED pattern”
PatternStageWhat it means
3 quick blinksBoot successfulBoard powered on, no hardware faults
5 slow blinks(Optional) Wi-Fi connectedIf you configured Wi-Fi via OTA
10 fast blinks(Optional) MQTT connectedIf the board is linked to a printer IP

For the component-test step, 3 quick blinks is what we’re checking for. The Wi-Fi and MQTT patterns are for the production-use step, not this one.

If the self-test fails

Section titled “If the self-test fails”

Work through these in order, they’re the most common failure modes we see in support:

  1. Actuator JST wires swapped (red and black reversed) Easy fix and extremely common. Open the JST housing on the actuator connector and swap the red and black pins. Fan or actuator behaviour that’s stuck in one direction usually traces to this.

  2. Actuator in the wrong PCB slot Confirm the actuator is plugged into the labelled actuator slot on the PCB, not the AMS slot. The connectors are similar enough to mix up on a tired evening.

  3. Old revision of the limit-switch holder The holder has been updated. If the switch lever can’t travel freely, or the switch is mounted upside down, reprint from the current MakerWorld bundle and reinstall. The lever must stick out enough to register a press from the moving z-axis.

  4. Fan JST wires worked loose in transit Some early units shipped with cold solder joints on the fan leads. Open the actuator, reseat or resolder the 24V leads, verify continuity with a multimeter.

  5. PCB LED check at boot (diagnostic)

    • D13 solid red + D7 solid red = good
    • D7 barely glowing = limit-switch wire broken, inspect the cable
    • Fan spins briefly at power-on then stops = normal

  6. Manual button-sequence check With the activation test G-code running, press the limit switch for exactly 4 to 5 seconds to start the fan. Outside that window nothing happens (this is a deliberate safety feature). Then triple-tap within about 3 seconds to trigger the actuator. If both respond, the hardware is fine and the issue is in the gcode or the app.

Quick symptom-to-cause map

Section titled “Quick symptom-to-cause map”
ObservationLikely cause
No LED at allPower not reaching the board; check AMS cable seating, swap USB-C cable
Fan doesn’t spinFan connector unseated or reversed; check the orange-cable plug on the PCB
Fan runs full speed and doesn’t stopJST wires swapped on the fan connector
Actuator doesn’t move4-pin actuator cable unseated or in wrong slot; check polarity
Actuator jammed in the “up” position right after installActuator wires reversed, see item 1 above
LED flashes 2 long, then rebootsBoard error; try USB-C reflash from Firmware

If none of these fix it, the board may be defective — we replace under warranty. Email contact@3d-farmers.com with photos and your order number.

What success looks like

Section titled “What success looks like”

Board self-test shows all three components respond on boot: fan, linear actuator, limit switch. If so, move on to the Activation test print — a real G-code that exercises the full end-to-end flow including cool-down timing and actual eject.

Section titled “Related”