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From: dalloff@freenet.columbus.oh.us (Dave Althoff)
Newsgroups: comp.sys.apple2
Subject: Re: Problem with IIe keyboard
Date: 4 Sep 1996 23:19:50 -0400
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I promised to post this...
If you can't get a solvent to clean your bad keyswitch, here are detailed
instructions for replacing the faulty switch...
A Guide to Replacing Apple ][e Keyswitches
------------------------------------------
By Dave Althoff, ][. (dalthoff@capital.edu)
NOTE: This document details the methods I have used to replace Apple
][e keyswitches. The procedure is fairly straightforward, but it
does involve completely disassembling your computer, desoldering the
old keyswitch, and resoldering the new switch. If you mess it up,
damage your computer, hurt yourself, or experience other
difficulties, I cannot assume any responsibility. As with any repair
or modification, proceed at your own risk.
Various comp.sys.apple2 correspondents have reported success with
cleaning Apple ][e keyswitches. I have not had much luck with this
myself, but I have replaced a bunch of the switches in one of my
][e's. The procedure is fairly straightforward. I have been able to
get replacement keyswitches from Micro Center (Columbus, Ohio) for
$10/each (Yikes!) for the Alps long-stem switch...which is also used
in the Macintosh Plus keyboard. Some ][e's use the Alps short-stem
key switch with an extension. If anyone knows a cheaper source for
these parts, PLEASE let me know!
1. Turn the computer off, ground yourself to the chassis, then
pull the plug on the machine.
2. Invert the computer and remove the Phillips head screws from
the perimeter. There are supposed to be three under the front
edge, and three more along each side edge. Some may be
missing (mine had only four). Do NOT remove the four smaller
screws which secure the power supply. With the screws removed,
turn the computer right-side up. Hold it together when you
do so!
3. Remove the top of the case. NOTE: There are two styles!!
3a. IF THE KEYBOARD IS NOT ATTACHED TO THE UPPER CASE:
i. Set the case lid aside.
ii. The keyboard is attached to two supports attached to the
computer's base pan. Mark the supports at the edge of the
keyboard assembly.
iii. Note the orientation of the ribbon connector either at the
edge of the keyboard, or on the motherboard, and unplug
the ribbon cable.
iv. Remove the four screws which secure the keyboard to the
supports, and remove the keyboard assembly. Proceed to
step 4.
3b. IF THE KEYBOARD IS ATTACHED TO THE UPPER CASE:
i. Note the orientation of the ribbon cable either at the
edge of the keyboard or on the motherboard, and unplug the
ribbon cable. Set the motherboard assembly aside.
ii. Remove the four screws which secure the keyboard to the
upper case and remove the keyboard assembly. Proceed to
step 4.
4. Locate the bad keyswitch, and remove the keycap by pulling
straight up. Also remove the keycaps from the surrounding
keys.
5. On the bottom of the keyboard, there are two solder points
beneath each keyswitch. Locate the solder points for the bad
keyswitch and COMPLETELY desolder the terminals using some
kind of vacuum desoldering tool. I use a squeeze bulb, but
the spring-loaded desoldering tools sometimes work better.
Be careful not to damage the printed circuit trace...do not
overheat the joint!
6. Now for the tough part. Squeeze together the tabs on either
side of the keyswitch post, and lift the keyswitch straight
up out of the keyboard assembly. If it won't come, then you
probably don't have all of the solder off of the connection
posts. Or you aren't squeezing the tabs enough.
7. Align the posts on the bottom of the new keyswitch with the
holes in the circuit board. It will only fit one way.
Press the keyswitch into the keyboard assembly until it
snaps into place.
8. Carefully solder the pins on the keyswitch to the circuit
board. Replace the keycaps.
9a. IF THE KEYBOARD WAS ATTACHED TO THE UPPER CASE:
i. Attach the keyboard to the upper case using the four
screws.
ii. Connect the ribbon cable between the keyboard and the
motherboard
iii. Proceed to step 10.
9b. IF THE KEYBOARD WAS ATTACHED TO SUPPORTS ATTACHED TO THE
BASE PLATE:
i. Align the edge of the keyboard with the mark you made
on the support in step 3a(ii).
ii. Attach the keyboard to the keyboard support bracket
using the four screws. Alignment is very important!
iii. Reconect the ribbon cable between the keyboard and the
motherboard.
iv. Proceed to step 10.
10. Drop the upper case onto the computer base plate, invert
the unit, and reinstall the screws from the bottom of the
case.
11. Reconnect the computer and test the keyboard. Make sure
that all of the keys work, in particular the key that you
replaced. Also, check all of the keys around the edge of
the keyboard, particularly the open-apple and tilde, to make
sure that none of the keys are jamming against the edge of
the case.
12. Go enjoy a beverage of your choice, as you have successfully
repaired your keyboard. The whole operation should take
about a half-hour.
--Dave Althoff, ][.
--
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