HP C7769B Service Manual - Page 73

Service Tests and Utilities Service Tests (Diagnostics) The following is a list of all internal Service Tests available in the Printer. Instructions for entering the Service Tests menu are given on Page 4-4. 1 Ink Supply Station ⇒ Page 4-6 The purpose of this test is to verify the operation of the Ink Supply Station. A failure of the out-of-ink sensors or the springs in the Ink Supply Station will eventually damage the Printheads because the Printer will try to pump ink from an empty Ink Cartridge stall, which will cause the Printhead to dry-fire. 2 Carriage Movement ⇒ Page 4-8 The purpose of this test is to verify the movement of the scan-axis components at several speeds. This test checks for the following problems: n Friction problems with worn out slider rod or Carriage Bushings. n Blockage due to problems with the Service Station. n Problems with encoder sensing. 3 Paper Advance ⇒ Page 4-10 The purpose of this test is to identify whether there is too much friction in the paper-axis drive system which is caused by defects with the Transmission Gears, Drive Roller or the Paper-Axis Motor. 4 Troubleshooting ⇒ Page 6-4 The Printer contains an internal Troubleshooting procedure which helps you to diagnose and resolve the possible source of any Image Quality or Line Quality defects. If Print Quality is poor at anytime, the Troubleshooting procedure should be performed which will determine whether the Printhead needs replacing (by marking it with an exclamation mark) or not after performing various levels of recovery actions. HP DesignJets 500 and 800 Series Printers Service Manual 4-3