!
error HP
Error Code 51.X Printer Error
Bad beam detect error - laser/scanner optical path problem.
? What Causes This
Laser beam detection failure, misaligned laser, or scanner assembly issue.
✓ How to Fix It
- Press the Go button to continue.
- Check for obstructions in optical path.
- Power cycle the printer.
- If error persists, contact service.
Source: page 142 of the official manual
From the manual
This error code appears in:
HP Laserjet 1010 Printer