HP Color LaserJet Managed MFP E78228

Troubleshooting. Blank display, black display, no display, or no power situation

Customers usually report that the control panel display is not showing anything. It is very important to collect as much information as possible from the customer about the issue to help resolve it.

Following are some printer behaviors the customer might encounter:

  • The control panel is completely blank (no LEDs or back light).
  • The control panel is blank, but there might be LEDs illuminated.
  • The control panel is blank (LEDs are on or flashing), and the back light is on (but no text is visible).

Following are some possible causes of a blank control panel display:

  • No power to the printer.
  • The control panel contrast setting is not correctly adjusted.
  • The formatter connector(s) are not fully seated into the connector(s) on the DC controller, or the connectors are not fully seated on the formatter.
  • A faulty component is installed on the formatter (for example a memory DIMM, fax PCA, network PCA, USB device, or other component).
  • The formatter is defective.
  • The control panel connector is not fully seated, or the control panel is defective.
  • The DC controller is defective.

Following are some questions to ask the customer:

  • Was the printer newly install or has the printer been properly functioning?
    – For a new install, investigate to see if there was any shipping damage to the printer.
    – Did the customer notice any damage to the shipping box or any visible damage to the printer?
  • What happened just prior to the control panel going blank?
    – Was the printer serviced recently, a power outage occurred?
    – Has a lightning storm recently occurred?
    – Did the customer recently add a memory DIMM or install a third-party component?
  • Make sure to get a complete description of the failure.
    – Is the control panel display completely blank (might be faint text and no back light)?
    – Is the control panel display back light on?
    – Has a print job been sent to the printer? The customer might report that their print jobs seemed to print but when they go to the printer the control panel display is blank.

Recommended actions

If the control panel display is completely blank (no LEDs illuminated or no back light) check to see if the printer is getting power. Listen for fans or any printer initialization sounds when the power is turned on.

If there are no signs of power, then perform the following:

  1. Make sure that the printer is plugged directly into an active electrical outlet (not a power strip or interruptible power supply) that delivers the correct voltage.
    TIP: Try using a different power cable if possible.
  2. Turn the printer power on, and make sure that the fan(s) run briefly (this indicates that the power supply is operational).
  3. Check if the yellow LED on the formatter is flashing. If so, there is a communication issue between the formatter and the control panel.
  4. Turn the printer power off.
  5. Make sure that the control panel display wire harness (and/or flat cable) is properly connected (and fully seated), and then turn the printer power on again.
  6. Check control panel diagnostics by pressing the button on the back of the control panel to run different diagnostic tests.
  7. Verify the status LEDs are illuminated, but the control panel display is blank. If applicable, check if the contrast setting is adjusted to very low. If so, try turning the contrast knob to see if the control panel display becomes visible.
  8. From a host computer, send a print job to the printer.
    NOTE: If the print job correctly prints, then the problem is most likely a defective control panel.
  9. Turn the printer power off, and then make sure that the memory DIMM is installed in the correct slot and is fully seated.
    NOTE: For some printers, there may be more than one memory DIMM installed. Some printers have third party solutions/applications or fonts that use memory.
  10. Remove all of the components/accessories installed on the formatter (for example, hard drive, solid-state drive, memory DIMM(s), fax PCA, network PCA, USB devices, or other devices).
    – Make sure that the formatter is fully seated.
    IMPORTANT: This is important because the formatter or a component on the formatter might be defective or shorted, which causes the printer to lose power.
  11. Reinstall the formatter. Make sure that it makes a good connection and is fully seated. Make sure that all of the connectors on the formatter are correctly connected and fully seated.
  12. Turn the printer power on, and then check the control panel display.
  13. If the printer control panel is properly working, replace each removed component (one at a time) to determine which one is causing the problem.
    CAUTION: Turn the printer power off, and then on again, after replacing a component on the formatter.
  14. If the control panel display is still blank after performing the above troubleshooting steps, and the control panel diagnostics do not function, replace the control panel. If the control panel diagnostics are functioning, then replace the formatter.
Error Code
Service Mode, Troubleshooting
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