HP LaserJet M506dn Enterprise
Diagnostic. Engine
The printer contains extensive internal engine diagnostics that help in troubleshooting print quality, paper path, noise, assembly, and timing issues.
Engine test button
To verify that the printer engine is functioning, print an engine test page. Use a small pointed object to depress the test-page switch located on the rear side of the printer. The test page should have a series of lines that are parallel to the short end of the page. The test page can use only Tray 2 as the paper source, so make sure that paper is loaded in Tray 2.
NOTE:
Depressing and holding down the test-page switch causes the printer to continually print test pages. Releasing the switch stops the test page continuous printing.