Model 4:

Note: Keep track of which screw goes where. Many of the screws need to go back into the same places they came from.

Steps:

1)
Remove the three screws under the keyboard.
2)
Remove the two screws located in a recess by the brightness and contrast adjustment wheels.
3)
If your Model 4 has a screw on the back top center, remove that. Not every Model 4 has this screw.
4)
Remove the five screws on the bottom: Two by the left rear, one by the right rear , one near the cassette port, and one near the edge connector. If you still have a warranty sticker, one of these screws is likely to be underneath it.

At this point all of the screws are out. However, great care must be taken when opening the case because the video tube and attachment can EASILY catch and break on the wires or the frame, so GREAT CARE must be taken with the next step. You can try to look through the floppy drive holes or the vents at the top of the model 4 to make sure you have cleared the CRT Tube.

5)
With the front of the Model 4 facing you, lift up a little and then pull forward a little. Tilt the cabinet to the left after you have cleared the video tube. Lay the cabinet/monitor on its left side (disk drive openings up).

Now you have it open, but you cannot fully access the internal as there is a RF shield present.

6)
Remove the RF shield screws and then the RF cover.

Model 4P:

Note: Keep track of which screw goes where. Many of the screws need to go back into the same places they came from.

Steps:

1)
Remove the front cover, if you still have one.
2)
Put the keyboard out of the way.
3)
Put the Model 4P face down on a soft surface.
4)
Remove the two screws on left and right side.
5)
Lift the handle and remove the two screws which are now exposed.
6)
That should be it for the outer case, so lift the outer case.
7)
Look at the motherboard – you should see either 4 or 5 screws on the side holding it down; remove those screws.
8)
Unhook the floppy drive connector (and remember where that was, and in what direction the cable was, for reassembly).
9)
Unhook the three connectors in the front on the left (and remember where each was, and in what direction each cable was, for reassembly).
10)
Remove the motherboard assembly.