Apple Self Repair Guides

Replacing Mitsumi Keycaps

Tools

• ESD wrist strap and mat
• Black stick (Apple part number 922-5065) or other nonconductive nylon or plastic flatblade tool

• Fine-point tweezers
• Needlenose pliers

Preliminary Steps

Before you begin, remove the battery.

Part Location

The Mitsumi keyboard comes in three versions: ANSI, ISO, and JIS. Refer to the following keyboard layouts to help identify them.

ANSI Keyboard Layout:

esc	■0> Fl	F2 J [ < F3 l| <1
	| 1	® # I $ 2 3 j 4	% A & j * | 1 5 6 c 7 7 ! 8 6 9 ,	°< _JlL	delete
lob		A 5	J/, Mil
caps lock		A I S j D	Hl g	-.liir	enter return
shifl		h *	c v T](T](T <	MNi	shift
oplion Ii Ö 3€ j	enter ^ ^hom- Jj pager	| end ►

ISO Keyboard Layout:

JIS Keyboard Layout:

Procedure

Like the Darfon keyboard, the Mitsumi keyboard is integrated in the top case and cannot be removed from the top case. The Mitsumi keyboard comes in three versions: ANSI, ISO, and JIS. The square keycaps for all three versions use the same dual-hinge mechanism inside the keycap well with one stabilizer bar inside the keycap.

For the Space bar replacement, the ANSI and ISO Space bar keycaps look the same: two singlehinge mechanisms and two stabilizer bars in the keycap well. The JIS Space bar keycap, by contrast, has two dual-hinge mechanisms and two stabilizer bars.

Once you are experienced replacing square keycaps and the Space bar, you can easily replace other size keys because of their shared traits. For example, the ANSI Return keycap has a dual-

hinge mechanism and one stabilizer bar; whereas the ISO and JIS Return keycap has no hinge mechanism and three stabilizer bars.

Important Tips:

Before installing a new keycap, make sure

• The clips on the underside of the keycap are not broken or bent.
• The hinge mechanism operates smoothly.
• The stabilizer bar is fully snapped into place
• The hinge mechanism is closed and slid farthest from the rubber dome before lowering the keycap over the keyboard well.

Removing and Replacing a Square Key

1. If a key needs to be removed (for example, if a key is sticking when pressed), pry it up from the

1. Because adhesive is used under the top case, closely inspect the case for any adhesive that may have built up under the keycap. Lift away any built-up adhesive using fine-point tweezers.
2. Note the stabilizer bar and clips on the underside of the keycap, and check that the dual-hinge mechanism lays flat.

4. Test the operation of the dual-hinge mechanism by using a black stick to carefully raise and lower the mechanism.

• If it is installed correctly, the hinged pieces should move smoothly.
• If it is damaged or loose, refer to the section "Reassembling the Hinge Mechanism."

5. Check that the stabilizer bar can pivot easily within the hooked ends of the keycap.

• If any of the hooks or clips are bent, broken, or missing, replace the keycap.
• If the hooks and clips are intact, re-use the keycap.

6. Check the rubber dome inside the keycap opening on the top case.

• When the rubber dome is pressed and released, it should spring back upright.
• If the rubber dome is off center or damaged, replace the top case.

7. With the stabilizer bar open, press the two ends of the slider bar into the slots in the keycap well so they snap into place.

8. Allow the dual-hinge mechanism to fold flat, and use a black stick to make sure the hinged pieces are pushed farthest away from the rubber dome (this is a tiny movement).

9. Carefully lower the keycap onto the top case, and press down on the center of the key until the keycap snaps into place.

10. Check the key from all angles to make sure it is uniformly flat. Press and release the key repeatedly to verify that it springs back each time.

Reassembling the Hinge Mechanism

This procedure shows images from a JIS keyboard; however, the steps for replacing the hinge mechanism are the same for any versions of the Mitsumi keycaps.

1.If a hinge piece becomes loose from the top case, check that the hinge piece is not damaged.

2. Check both sides of the hinge piece. Note that the top plane of the hinge piece has two barely visible recessed circles, and the end pins fit into the hooked slots on the anchored plane inside the keycap well.

3. With the hinge piece held vertically, position it into the hooked area (1), and slide it forward (2) so it becomes anchored in place and can fold down fully flat.

Replacement Note: If the hinge piece is upside-down, it will not lay fully flat.

Removing and Replacing an ANSI or ISO Space Bar

1. If a Space bar needs to be removed (for example, if it is sticking when pressed), pry it up from the top edge first.

2. With the top edge loosened, pry up the Space bar from the lower edge. Use a black stick, if necessary, to tilt up the key.

1. Because adhesive is used under the top case, closely inspect the case for any adhesive that may have built up under the keycap. Lift away any built-up adhesive using fine-point tweezers.
2. Check that the longest stabilizer bar can pivot easily within the four hooks of the keycap.

• If any of the hooks or clips are bent, broken, or missing, replace the keycap.
• If the hooks and clips are intact, re-use the keycap.

5. Check the rubber dome inside the keycap well on the top case.

• When the rubber dome is pressed and released, it should spring back upright.
• If the rubber dome is off center or damaged, replace the top case.

1. With the stabilizer bar open, make sure the two ends of the slider bar are secured into the slots in the keycap well.
2. Make sure the single-hinge mechanism on both ends of the keyboard well is fully flat and pressed as far as it will go away from the rubber dome. Then lower the keycap so that the three clips align with the smaller stabilizer bar.

8. Lower the key down.

9. Press the major contact

0 0