Question about HP LaserJet 2420 Printer
Hi, Printer Has Blank Display Issue Description: Some customers may report that the control panel display is not working on their LJ2400 Series printer. Most of the units are right out of the box. This goal of this document is to help you troubleshoot the problem and provide a solution for the customer. Symptoms Customers will see: Printer powers on, motor rotation and fan sounds can be heard during boot cycle, but the control panel display is blank and there is no backlight . Printer prints engine test page. Printer powers on, motor rotation and fan sounds can be heard during boot cycle, but there is backlight . Printer prints engine test page. Troubleshooting requested by engineers: BACKLIGHT PRESENT, BUT NO TEXT DISPLAYS Disconnect all connections to printer except for power cord. Plug power cord directly into wall outlet and power cycle. Can motor rotation sounds be heard? Reseat memory DIMM in slot. Check cable connections on formatter ? particularly control panel power (J4), ECU-Formatter flat ribbon cable (J5), and power from the ECU (J6). NO BACKLIGHT Verify that the engine is powering up when power cycled by listening for motor rotation sounds. Ask the customer to print an engine test page. (See photo below for access to engine test page button.) If engine does NOT print test page, problem is with the engine, not formatter or control panel. (Service required.) Check cable connections on formatter ? particularly control panel power (J4), ECU-Formatter flat ribbon cable (J5), and power from the ECU (J6). Verify boot select jumper on the formatter PCB is installed on the bottom two (correct) pins (see photo below) to ensure the unit ?boots? from the firmware chip on-board the formatter. NOTE: The BOOT SELECT position (top two pins) is only used to boot from a FW-loaded compact flash card. If incorrect, reseat boot select jumper onto the bottom two (correct) pins. Attempt to print a configuration page ? ?back? button (x3, to clear any undisplayed messages) -- check button -- down arrow -- check button -- down arrow -- check button. If configuration page prints, verify contents and, assuming you find nothing wrong with configuration, you may assume that the problem lies with the display portion of the control panel. Rgds, Nikhil
Posted on Sep 09, 2009
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Posted on Jan 02, 2017
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