print-unable-03MFC-EX720

Brother MFC-EX720 print unable 03 error: Sensor fix

The Brother MFC-EX720 print unable 03 error signals a tray detection sensor fault. The machine cannot confirm the tray is installed, locking the printer.

1 views

Common causes

  • 1Sensor blockage.
  • 2Debris in tray area.
  • 3Micro-switch failure.
  • 4Electronic board fault.

Solutions

Quick Diagnosis

If the printer ignores the presence of the paper tray, the sensor switch is stuck.

Step-by-Step Solution

  1. Disconnect printer.
  2. Remove tray.
  3. Clean the tray area.
  4. Reseat tray.

Prevention and Maintenance

Avoid slamming the tray into the unit.

When to Call a Technician

If the tray switch is physically broken, it must be replaced.

Device Technical Sheet

  • Technology: Inkjet.
  • Performance: 30 ppm.
  • Connectivity: Wi-Fi/USB.
  • Consumable: LC75/LC79 ink.
  • Support

Steps to follow

  1. 1

    Check Tray

    Verify the tray locks correctly.

  2. 2

    Reset

    Reboot after cleaning.

Frequently asked questions

Tray detection sensor isn't working.

No, the printer requires the tray to be verified.

Original inks prevent internal clogging.

The switch might need professional service.