HP LaserJet 6L Service Manual - Page 142

7 Troubleshooting Figure 7-4 Troubleshooting Checks Engine Test The engine test print is used to verify that the print engine is functioning correctly. The Formatter PCA is completely bypassed during an engine test, so this test is useful for isolating printer problems. The engine test prints a full page of vertical lines down the entire printable area and is also useful for checking and adjusting registration. Engine Test Button Location The engine test print button is located on the DC Controller PCA. It is accessible through a hole at the front of the printer. (See Figure 7-4.) Printing an Engine Test The engine test button is accessible without removing the covers. To print an engine test, use a long, non-metallic object (such as a pen or pencil) to press the engine test button. A single test page is printed. (See Figure 7-4.) Engine Test Troubleshooting 7-21