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FAQ & Troubleshooting

Common PikkoBot-specific issues and fixes. For issues not listed here, email [email protected].

OpenPnP Won't Start​

  • Symptom: the installer finishes, but launching OpenPnP shows an error immediately or the window flashes and closes.
  • Cause: OpenPnP 2.6 needs Java 11 or newer. A Java 8 runtime throws a startup error that reads like a corrupt install.
  • Fix: run java -version in a terminal. If it reports 1.8 or the command isn't found, install a current JDK and try again. On macOS and Linux the installer does not bundle a JRE.

Solenoid Valve Won't Open in OpenPnP​

  • Symptom: in the Debug page, the air pump and solenoid valves turn on normally, but during a job the valves don't open.
  • Cause: the actuator G-code uses a value of 180 for the solenoid, but the firmware expects 255 to fully open.
  • Fix: Machine Setup → Actuators → find VAC1 and VAC2 → change S180 to S255 for both → save and test.
Solenoid G-code fix Valve dialog Actuator config

This fix is already applied in the (JUKI) configuration files on the Downloads page. If you're seeing it, you're probably running a stock config.

Pressure Sensor Error / Pop-up Warning​

  • Symptom: OpenPnP shows a pressure sensor failure or vacuum pressure out-of-range error.
  • Cause: PikkoBot v4 ships without a vacuum pressure sensor and uses bottom-camera vision instead; OpenPnP's default sensor check always fails.
  • Fix: Machine Setup → Heads → Nozzles → Nozzle 1 → find Vacuum Sensing → set Method to None → repeat for Nozzle 2.
Pressure error popup Pressure sensor setting

FIDUCIAL-HOME: No Matches Found​

  • Symptom: homing fails with FIDUCIAL-HOME no matches found.
  • Cause: the fiducial detection pipeline can't find the 1 mm dot on the datum board — usually because of exposure, lighting, or a size filter left over from a different resolution.
  • Fix: work through the checklist on Homing & Fiducial — camera position, LEDs on, exposure histogram, then the pipeline's diameter range.

Every Board Comes Out Offset by the Same Amount​

  • Symptom: placement is consistently off in the same direction on every board, including the first one.
  • Cause: a uniform offset is almost never calibration — it's the machine's XY datum. The captured homing fiducial location is slightly off centre.
  • Fix: re-capture the homing fiducial location. See Homing & Fiducial. If the offset changes with board position instead of staying constant, that's a different problem — go to MM/Pixel Calibration.

Placement Drifts Across the Board​

  • Symptom: components near the origin are close, components further out are progressively further off.
  • Cause: MM/pixel scale error, not an origin error.
  • Fix: re-run MM/Pixel Calibration.

Controlling Top and Bottom LEDs Separately​

Send G-code manually via Machine → Send G-code:

M150 S 0 ; Top LED off (S0 = top)
M150 S 1 ; Bottom LED off (S1 = bottom)
M150 P 255 S 0 ; Top LED full brightness
M150 P 255 S 1 ; Bottom LED full brightness
M150 P 128 S 0 ; Top LED half brightness

The S parameter selects the LED strip; P sets brightness (0–255).

LED control

Machine Makes Grinding Noise During Homing​

  • Symptom: grinding or skipping sound when homing an axis.
  • Likely causes: motor current too low; axis obstructed (snagged cable, debris); limit switch not triggering; on Z, a dry lead screw.
  • Fix: check nothing is physically blocking the axis; check limit switch cables are connected; put a light PTFE grease on the Z lead screw. If the axis moves freely by hand but grinds under power, motor current may need adjustment — contact support.

Debug vs OpenPnP Behavior Mismatch​

  • Symptom: things work in the hardware Debug page but behave unexpectedly in OpenPnP.
  • Cause: OpenPnP sends G-code through its own actuator layer with different parameters.
  • Fix: compare the G-code in Machine Setup → Actuators with what the Debug panel sends, and update the actuator G-code to match working values.

Top Camera Is Black or Stuttering​

  • Symptom: no image, or dropped frames during a job.
  • Likely causes: lens cap still on; exposure set to zero after a config load; both cameras sharing one USB controller; resolution or frame rate set higher than the USB link handles.
  • Fix: check the lens cap first. Then set the top camera to 1280x720 at 10 fps — the low frame rate is deliberate and prevents bandwidth problems. If it still stutters, move the two camera USB cables onto separate controllers.

Feeder Not Detected After Mounting​

  • Symptom: a mounted feeder doesn't appear in OpenPnP, or a previously working feeder goes missing.
  • Likely causes: no power on the bus, duplicate UUID address, or a stale feeder list.
  • Fix: see the troubleshooting section on Feeder Overview — status light, address conflicts, manual step test.

Machine Homed to the Wrong Place​

  • Symptom: the head parks somewhere unexpected, or moves oddly after homing.
  • Cause: homing method or the captured homing fiducial location changed — often after loading a different configuration file.
  • Fix: confirm Homing Method is set to ResetToFiducialLocation, then re-capture the homing fiducial location. Loading a config from another machine overwrites the captured location with that machine's values.

Nozzle Picks at an Angle, or Drops Parts Mid-Job​

  • Symptom: parts pick, then sit rotated or off-centre on the nozzle; or small parts pick intermittently while large ones are fine.
  • Cause: the nozzle is worn, contaminated, or the wrong aperture for the part. Tip outer diameter is the limiting dimension — a 503 (1.0 mm tip) is not the right nozzle for a 1206 chip, however well it seems to work most of the time.
  • Fix: check the component against the Juki Nozzle Compatibility table, clean the tip with isopropyl, and go down a nozzle number if small parts are the ones failing. After any nozzle change, re-run nozzle tip calibration with the bottom camera — every nozzle number has a different tip length.

Support​

  • Email: [email protected]
  • Include your machine version, the OpenPnP error text, and a photo or screenshot — it usually saves a round trip
  • Downloads — configuration files and OpenPnP installers
  • Homing & Fiducial — the calibration step most support questions trace back to
  • Juki Nozzle Compatibility — which nozzle number for which component