How to Fix Printer Error 51 : (Loss of beam detect)

HP Printers and others have a lot of little basic bugs, but if you know how to deal with some of the more habitual problems you will make the printer your friendly companion to your tasks and projects.

Possible Causes and Solutions:
IIP/IIP+/IIIP
• Improperly seated toner cartridge - remove and reinstall
• Laser shutter blocked or damaged
• Damaged fiber optic cable
• Defective Laser PCA - replace
II/IID/III/IIID
• Defective toner cartridge - Replace with different cartridge, even empty for testing
• Bad or loose cable connectors - Scanner to DC Controller - check and tighten connector pins at both ends of cable
• Damaged Fiber optic cable - examine for cuts or kinks, replace as necessary
• Defective Scanner Assembly - Replace RG5-0050
IIISi/4Si
• Defective Toner Cartridge - Replace with different cartridge, even empty for testing
• Fiber Optic cable - examine for cuts kinks, nicks.
• Faulty Connectors - Check J002 on DC controller and J601 on Laser PCA
• Low DC Voltage - Verify 12 VDC at J601-2 on Laser PCA
• Defective Scanner Assembly - Replace Laser Scanner Assembly
4/4+/5
• Faulty Laser Scanner Cable Connectors - Remove and Reseat connectors
• Defective Laser Scanner Assembly - Replace RG5-0049