print-unable-04MFC-EX720

Brother MFC-EX720 print unable 04 error: Motor failure

The Brother MFC-EX720 print unable 04 error is a critical fault indicating the main motor is unresponsive. The printer cannot complete initialization.

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Common causes

  • 1Motor failure.
  • 2Board surge damage.
  • 3Disconnected tachometer.
  • 4Power supply fault.

Solutions

Quick Diagnosis

If the motor does not engage on boot, it is a hardware-level failure.

Step-by-Step Solution

  1. Disconnect and reset.
  2. Inspect for unusual smells.
  3. Check power stability.
  4. Power up again.

Prevention and Maintenance

Use a surge protector to prevent power spikes.

When to Call a Technician

If the motor is unresponsive after a power cycle, motherboard repair is needed.

Device Technical Sheet

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

Steps to follow

  1. 1

    Power Cycle

    Leave disconnected for 30 minutes.

  2. 2

    Direct Power

    Plug directly into a wall outlet.

Frequently asked questions

Main motor rotation detected failure.

Usually requires professional motor/board testing.

Yes, always use original cartridges.

Consult a professional to get a quote on motor replacement.