HP LaserJet 4 Service Manual - Page 189

DC Controller Installation Caution When reinstalling the DC Controller PCA it is extremely important that all cables be properly routed. If cables are not routed properly, it is difficult to reinstall the Formatter Cage and cable damage may result. When replacing the DC Controller, be sure to set the leading edge adjustment as shown in the following procedure. Note The Leading Edge Adjustment is set at the factory and is not required as a maintenance procedure. The Leading Edge Adjustment should be done only when the DC Controller is replaced. The following procedure is performed with the Formatter Assembly removed. To set the Leading Edge Registration: 1 Install the new DC Controller in the reverse order of the removal. 2 Run a test print to check the leading edge adjustment (as shown in Figure 6-28. 3 Use VR202 (LaserJet 4) or VR201 (LaserJet 4 Plus and 5) (see Figure 6-29) to adjust the leading edge registration to the dimension shown in Figure 6-28 (a=2mm). 4 Make several test prints (15 ENGINE TEST as shown in Figures 3-5 and 3-6) and check the adjustment. Repeat the above steps until the adjustment is correct. 6-35 Removal and Replacement