173C711dn

OKI C711dn Error 173: Duplex Unit Connection Fault

Error code 173 indicates that the OKI C711dn motherboard cannot establish electrical communication with the duplex unit installed at the back of the machine.

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Common causes

  • 1Duplex unit is slightly dislodged or loose.
  • 2Paper scraps or debris blocking the connector port.
  • 3Bent connection pins on the main printer side.

Solutions

Reseating and Cleaning the Duplex Interface

This connection issue is often caused by micro-movements of the duplex housing during high-volume print runs, or oxidation of the electronic connecting pins.

  1. Inspect Alignment Guides:
    The duplex unit must sit completely flush against the back frame. If one of the locking tabs is worn or damaged, the unit may tilt, disrupting the connection.
  1. Check the Port Connector:
    The electrical bridge at the rear center has several copper pins. Ensure no paper shreds are caught inside and that none of the spring pins are bent.

Steps to follow

  1. 1

    Power Off

    Turn off the printer power switch and unplug the device from the electrical source.

  2. 2

    Remove the Duplexer

    Hold the rear duplex unit firmly and pull it straight out of the printer housing.

  3. 3

    Clean Connection Contacts

    Inspect and clean the interface pins using a can of dry compressed air or an electrical contact cleaner.

  4. 4

    Firm Reinsertion

    Push the duplex unit back in with balanced force until it clicks flush against the chassis, then power back on.

Frequently asked questions

Yes, you can physically remove the duplexer and change your printer preferences in your operating system to single-sided (simplex) printing to continue operating.

Inspect the gold pins inside the rear cavity. If any pins are missing, broken, or pushed too far into the housing, the unit or mainboard will need repair.