600B4402

OKI B4402 error 600: Main Motor Failure Detected

The OKI B4402 error 600 is a service error code indicating a failure in the rotation of the main motor. This motor is responsible for driving both the drum and the paper transport system, so any mechanical impedance stops the printer immediately. The B4402 is a high-performance monochrome laser printer.

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Common causes

  • 1Mechanical obstruction in the drum unit.
  • 2Motor controller (PCB) failure.
  • 3Dirty gears or lack of lubrication.
  • 4Main motor with open winding.

Solutions

Quick Diagnostics

The 600 code appears when the motor controller detects zero RPM despite voltage being sent. This usually occurs due to a drum jam or an electrical failure within the motor itself.

Step-by-Step Solution

  1. Turn off the printer and remove the toner and drum cartridge.
  2. Attempt to rotate the drum gear manually to check if it is locked.
  3. Check the printer interior for paper jammed in the exit area.
  4. Clean the cartridge contacts and reinstall firmly.

Prevention and Maintenance

Clean internal gears with a soft brush every six months. Avoid leaving the printer in dusty areas, as dust compacts into gear grease, increasing friction. Always use brand-name consumables to avoid toner leaks.

When to Call a Technician

If, after removing the cartridge, the motor attempts to turn but makes strange noises or stalls, the main motor needs professional replacement.

Technical Data

  • Technology: Digital LED Laser
  • Speed: Up to 26 ppm
  • Connectivity: USB, Parallel
  • Capacity: 250-sheet tray
  • Compatible Consumables: B4400 cartridge series
  • Recommended Use: Medium load offices
  • Official Drivers / firmware

Steps to follow

  1. 1

    Full power down

    Unplug the power cable for two minutes.

  2. 2

    Internal inspection

    Open the front cover and check that the toner/drum rotates freely.

  3. 3

    Power up

    Reconnect and turn on to test initialization.

Frequently asked questions

The main motor cannot rotate due to overload, lack of lubrication, or a physical jam.

If it's a simple jam, yes. If the motor is burnt, no.

It uses the B4400/B4600 series toner.

Keep the equipment dust-free and use genuine consumables to prevent blockages.