Lexmark T620 Service Manual - Page 91

4069-5XX/7XX Fan Service Check Printhead Fan Service Check The printhead fan is in models 722/72n. Note: If the printhead fan is inoperative and a lot of graphics are printed, you may see darker than normal copies. Fan does not run or is noisy. FRU 1 Fan Assembly 2 System Board Action Check the fan for proper installation and for excessive noise. If incorrect, replace the fan and cable assembly. Check to make sure the printhead fan cable is seated on connector J4 on the system board. If correct, check for +24 V dc on J4-1 on the system board. If incorrect, replace the system board. If correct, replace the fan assembly. Note: When the printer is in warmup the voltage at J4-1 measures approximately +12 V dc. When the printer is running, the voltage measures approximately +24 V dc. Main Fan Service Check Check the cable connections at J5 on the system board and at the main fan assembly. The main fan runs continuously when the printer is powered on unless the printer is in the Power Saver mode. FRU 1 Main Fan Action Manually spin the fan and check that it rotates freely. Check the cable connection to the system board, J5 for correct installation. Diagnostic Information 2-63