3 - 76 Phaser 840/850/860/8200 Color Printer - Service ManualElectronics TroubleshootingSystem power-up sequenceThe following lists the chain of events that occur when you turn on a printer. You canfollow this list as one means of determining if the printer is operating correctly. The exactchain of events depends upon the DIP switch settings, the last power down condition andwhere the printer ìbelievesî the printhead is positioned. The printer records innon-volatile RAM the last known position of the printhead and the cap/wipe/purgeassembly. The Electronics Troubleshooting Checklist is the primary reference fortroubleshooting power-up problems, see "On-site Electronics Troubleshooting ChecklistPhaser 840/850" on page A-250 or "On-site Electronics Troubleshooting Checklist Phaser860/8200" on page A-266.Phaser 840/850 Customer Mode Power-Up SequencePower switch is turned on:1. Power supply senses AC line voltage conditions (110 VAC or 220 VAC) and enablesDC voltages. If an overload occurs, the printer turns off the DC supplies, giving aìblinkî effect to the front panel LEDs.2. Low-level, power-on self-test (POST) diagnostics are performed. The two status LEDsat the rear panel should toggle and the front panel LEDs are turned on. The front paneldisplay is blank. This test takes from 4 to 15 seconds depending on installed RAM.3. If POST diagnostics pass, the front panel Error LED is turned off and the front paneldisplays the Tektronix logo while the mechanical initialization checks are performed.If an error is detected, the Phaser 850 printer flashes the front panel Error LED with arepeating error code pattern as well as the rear panel PS LED. On the Phaser 840printer, the pattern is displayed only on the rear panel PS LED (left side of the DIPswitches).4. The mechanical initialization is conditional on the initial position of the printhead andcap/wipe/purge assembly. Two NVRAM parameters are checked for the last knownposition.If the printhead is in either the Locked or Print position:a. The cap/wipe/purge motor is run to ensure that the cap/wipe/purgeassembly activates its home-position sensor.If the printhead is in the cap/wipe/purge position:a. The heaters in the printhead and cap/wipe/purge assembly are activated, asa precaution, to melt the ink which may have cooled and solidified, thusgluing the cap/wipe/purge and printhead together. 10 minutes pass whilethe cap/wipe/purge assembly heats up.b. The printhead is tilted back.c. The ink is allowed to drain from the cap/wipe/purge assembly.d. The cap/wipe/purge assembly is lowered to its home position.
