!!
critical HP
Error Code LED stays red constantly
Indicates the control-panel showing an error message during power-up phase.
? What Causes This
Configuration issues or hardware malfunctions during initialization steps.
✓ How to Fix It
Refer to step number 2 in troubleshooting check list for corrective actions such as verifying fuser locks, print cartridge installation and cover closure status.
Source: page 310 of the official manual
From the manual
This error code appears in:
HP Laserjet 3050 All IN One Printer