HP Laserjet 4 Manual
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6Remove the (2) connectors (6 wire and 3 wire). (See Figure 6-15, callout 1.) Squeeze the release tab on the 6-wire connector. Pull the 3-wire connector straight up. 7Remove the power supply. NoteWhen replacing the power supply, be sure to use the screws with the star washers to ensure proper grounding and RFI shielding. Figure 6-15 6-wire and 3-wire Connectors for the Power Supply Removal and Replacement 6-17
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Paper Feed Assembly Removal 1Remove the Right Side Cover, the MP opening cover, (see Figure 6-17), the Top Cover and the Left Side Cover, the Font Door Cover, and the PC tray (Tray 2). The MP tray need not be removed, but is shown removed for clarity. 2Remove the MP Tray (Tray 1) door, the Front Cross-member (Figure 6-11), and the MP Tray. 3Disconnect the 13-wire connector and the 4-wire connector from the front of the Paper Feed Assembly (see Figure 6-16, callout 1). 4Remove the (2) screws from the right side of the Paper Feed Assembly (see Figure 6-16, callout 2). (continued on next page) Figure 6-16 Paper Feed Assembly Screws and Connectors 6-18 Removal and Replacement
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(continued on next page) Figure 6-17 MP Tray Opening Cover Removal and Replacement 6-19
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5Remove the (3) screws from the left side of the printer (see Figure 6-18, callout 1). 6Remove the Paper Feed Assembly by lifting it and sliding it out the front of the printer. NoteReplace the screws in order as shown. (1-2-3 is also scribed on the printer chassis.) Tightening these screws in the wrong order can cause paper skew problems. Figure 6-18 Paper Feed Assembly Screws (numbered) 6-20 Removal and Replacement
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High Voltage Power Supply (HVPS) Removal 1Remove the Toner Cartridge and PC tray. 2Lay the printer on its left side. (Place a cloth under the printer to prevent marking the cover.) 3Remove the (2) screws that hold the HVPS in place (see Figure 6-19, callout 1). 4Release the (2) latches that hold the High Voltage Power Supply (see Figure 6-19, callout 2). 5Pull the HVPS straight away from the printer to clear its locator pins and to prevent damage to the HVPS connectors. 6Remove the HVPS from its housing by releasing the (4) retaining clips that hold the PCA in place. Note Run a printing self-test after replacing the high voltage power supply. If the printer prints solid black pages, the HVPS may be seated incorrectly. Repeat the installation procedure, being careful to align the high voltage connectors. Figure 6-19 HVPS Screws (2) and Latches (2) (Bottom View) Removal and Replacement 6-21
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Fuser Assembly Removal CautionThe Fuser Assembly may be hot. Allow plenty of time for the fuser to cool before beginning the fuser removal procedure. 1Open the rear door. 2Remove the (2) screws that hold the Fuser to the printer frame (see Figure 6-20, callout 1). 3Slightly lift the Fuser by both the right and left sides to clear the locator points. 4Pull the Fuser from the printer. NoteThe Fuser Assembly from the LaserJet 4 cannot be interchanged with the Fuser Assembly from the LaserJet 4 Plus or 5 printers. Figure 6-20 Fuser Assembly Screws 6-22 Removal and Replacement
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Control Panel and Overlay Removal 1Remove the Right Side Cover and the Top Cover. 2Turn the Top Cover over and place it on flat surface. 3Release the (3) latches that contain the Control Panel (see Figure 6-21, callout 1). 4Carefully pivot the Control Panel away from the Top Cover. (continued on next page) NoteTo remove the LaserJet 5 Control Panel, first remove the black screw securing the grounding leaf spring and the Control Panel plate to the Top Cover. Release the two latches at the top of the Control Panel Assembly and pivot the top of the assembly up and out of the printer. Figure 6-21 Control Panel Latches Removal and Replacement 6-23
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5If you must replace the Control Panel Overlay, release the (2) retaining tabs from the Control Panel and separate the overlay from the Control Panel (see Figure 6-22, callout 1). 6Squeeze the sides of the Control Panel Overlay to release the (2) tabs (see Figure 6-22, callout 1). 7Tilt the Overlay up and out. NoteTo remove the Control Panel Overlay on the LaserJet 5 printer, first remove the Control Panel Assembly and then slide the Overlay out of the side of the Top Cover. Reinstalling the Control Panel Assembly will secure the Overlay in place. Figure 6-22 Changing the Control Panel Overlay 6-24 Removal and Replacement
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Removing the SIMMs Door 1Remove the Right Side Cover. LaserJet 4: 2Remove the (2) screws that hold the SIMMs cover (see Figure 6-23a, callout 1). 3Open the SIMMs cover, lift the door slightly to remove the door from the hinge. (continued on next page) Figure 6-23a Removing the SIMMs Door (LaserJet 4) Removal and Replacement 6-25
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LaserJet 4 Plus/5: 2 Remove the (1) screw that holds the SIMMs cover (see Figure 6-23b, callout 1). 3 Swing open the SIMMs cover. Figure 6-23b Opening the SIMMs Door (LaserJet 4 Plus) 6-26 Removal and Replacement