HP Laserjet 4 Manual

Left Side Cover Removal 
1Remove the Right Side Cover and the Top Cover.
2Release the 2 latch points on the Left Side Cover (front latch
first) see Figure 6-5. The latches are on the inside of the Left
Side Cover.
3Fold out the cover and remove.
NoteWhen removing the LJ 5 left side cover, you must
gently push the Tray 1 cover forward to enable
the left side cover to be folded out and removed.
Figure 6-5 Left Side Cover Latches
Removal and Replacement  6-7 

Rear Door Removal
1Remove the PC tray (Tray 2).
2Open the Rear Door. Support the door with one hand.
3Release the door support from the rear of the printer frame as
follows: (see Figure 6-6)
aUsing needle-nose pliers, squeeze the tabs on the end of the
retaining strap. Slide the strap up and out of the printer
frame.
bRelease the retaining strap tab from the slot in the printer
frame.
cLift the tab to free it from the slot.
(continued on next page)
Figure 6-6 Releasing the Door Support
6-8 Removal and...

4LaserJet 4/5: Flex the Rear Door to release it from its hinges.
Press the middle of the door while lifting either side (Figure 6-7a).
LaserJet 4 Plus: Remove the Rear Door Attaching Clip
(Figure 6-7b, callouts 1 through 3).  Slide the Rear Door as far
as possible toward the left, then rotate to remove (Figure 6-7b,
callouts 4 and 5).
Figure 6-7a Releasing the Door Hinge (LaserJet 4/5)
1
2
3
A
B
5
4
Figure 6-7b Releasing the Door Hinge (LaserJet 4 Plus)
Removal and Replacement  6-9 

Font Door Cover Removal  (LJ 5 Right Front
Cover Removal)
LJ 4/4 Plus
1Remove the Right Side Cover, the Top Cover,and the PC Tray.
2Release the top latch (see Figure 6-8, callout 1).
3Release the (2) lower latches through the access hole in the
metal cover (see Figure 6-8, callout 2 and Figure 6-9, callout 1).
4Remove the Font Door Cover.
NoteFigure 6-9 shows the metal side cover removed in
order to show the Font Door latches. It is not
necessary to remove the metal side cover to
remove the Font Door.
LJ...

Figure 6-9 Font Door Cover Latches
Removal and Replacement  6-11 

Multi-Purpose (MP) Tray (Tray 1) Door Removal
1Remove the PC Tray.
2Open the MP Tray door and extend the MP Tray.
3Bend the Door Slides out to release the tray from the door
slides (see Figure 6-10). Place the inner door in the “up”
position.
LJ 4/4 Plus
4Flex the MP tray at the lower middle and release the door
from its hinges (seeFigure 6-10).
LJ 5
 4   Slide Tray 2 to the right to release it from its hinges.
Figure 6-10 Removing the MP Tray Door
6-12 Removal and Replacement 

Multi-Purpose (MP) Tray (Tray 1) Removal
1Remove the Right Side Cover, Top Cover, Left Side Cover, MP
Tray Door (Tray 1), and the Font Door Cover.
2Remove the PC Tray (Tray 2).
3Remove the (2) screws in the Cross-member Bracket as shown
in Figure 6-11, callout 1. Remove the Cross-member Bracket.
(continued on next page)
Figure 6-11 Remove the Crossmember Bracket 
Removal and Replacement  6-13 

4On the LJ 4+ and LJ 5 you must release the tray tension
spring located at the left side of the tray.  Use a pair of
needlenose pliers to remove the spring from the tray.
5Rotate the tray down until it slides off its slotted hinges (about
120°)(see Figure 6-12).
Figure 6-12 Rotate the Tray Down to Release the Hinge from
its Slots
6-14 Removal and Replacement 

Assemblies Removal
Power Supply Removal
1Remove the Right Side Cover.
2Remove the (3) or (2) screws from the metal cover at the lower
right corner of the printer (see Figure 6-13a or b, callout 1.)
Remove the metal cover.
NoteNote which end of the connecting rod is installed
into the Power Supply and which end connects
into the Rocker Switch.
3Remove the Power Switch Connecting Rod (callout 2.)  
alift the rod clear of tab (callout 3), and remove from socket
(callout 4).
bRemove the rod from the Rocker...

4Remove the (2) screws from the bottom frame (see Figure 6-14,
callout 1).
5Slide the power supply out the right side of the printer to
access the power supply connectors.
(continued on next page)
Figure 6-13b Remove the Sheet Metal Plate (LaserJet 4 Plus/5)
Figure 6-14 Power Supply Screws 
6-16 Removal and Replacement