[net.micro.mac] Repairing the Mouse

jer@peora.UUCP (J. Eric Roskos) (01/09/86)

Recently my mouse stopped working; the cursor would still move up and down,
but not right and left.  When I took it to my local repair shop, they
told me "there's nothing inside we can fix, so you'll have to buy a new
one".  This was a very expensive proposition, so I decided to try to fix
it myself.

In this case, at least, it turned out to be very easy to do, so here is
what I did... if yours quits and you find you have no alternative but to
buy a new one, you might try this before giving up.

1) Disassemble the mouse by removing the two screws on the bottom.
Inside, the cable is connected to the PC board by a rectangular plastic
connector, and also is soldered to a microswitch.  A strain relief for the
cable is pressure-fitted into the top of the mouse; pull this out of the
top of the mouse so you can set the top half of the mouse aside.  Be
careful not to lose the small coil spring that's attached to the mouse
button inside the top of the mouse.

2) Pull the microswitch upward to unfasten it.  It sits between a plastic
fork, and is held in place by the top of the mouse when it is screwed
together.  This will free the wires from the mouse cable, which run
under it.

3) Disconnect the rectangular connector.   The cable should now be free
of the bottom and top halves of the mouse.

4) Cut off the mouse cable about 1/2 inch beyond the point where it comes
out of the strain relief (on the outside-side of the strain relief).
Pull the cut off cable out of the strain relief.  (This takes some
effort, since it is stuck somewhat firmly into the strain relief, but
it's not molded on, so it does come off.)

5) Inside the rectangular connector, you can see the spring contacts to
which the wires are connected, through slots.  They are held into the slots
by small springs embossed into each contact.  Using a small screwdriver,
press each spring in turn while pulling on the attached wire, in order
to get it to come out of the connector.  Don't pull too hard or the wire
will break off, making it harder to get the contact out.  Be sure to
note which color wire went in what position, e.g. by marking the
connector beforehand.

6) Strip the outer insulator from the mouse cable to the same length it
was formerly stripped inside the mouse.  Strip and tin a very short segment
of each of the cable wires.  Stick this new cable through the strain relief
(be sure to go into the proper end) until the tan insulation shows through
the other end of the strain relief.

7) Solder these wires onto the spring contacts (the original wires were
crimped on, but you can solder the wires onto the crimped part of the
contact if you are careful).  It helps to also tin the contact where you
are soldering, first.  [Note that these contacts are gold-plated,
incidentally.]  Cut off each stub of old wire from the contact before
you solder the new one (of the same color) on.  Don't do the black wire
(which has two wires on the same contact) yet.

8) Pull off the heat-shrink tubing from the *yellow* wire connected to the
microswitch, unsolder the old yellow wire, slip the heat-shrink tubing
over the new yellow wire, carefully solder the new yellow wire onto the
microswitch, and slip the piece of heat shrink tubing onto the contact
while it is still warm (this makes it easier to get the tubing to go on).

9) Cut off the black wires from their contact at the contact end.  Leave the
black wire that's soldered onto the microswitch connected to the
microswitch, and strip the other end of it to be soldered back onto the
contact.  Now solder the black wire from the cable, and the microswitch's
black wire, in the same way they were connected before, to the contact.

10) Now stick the spring contacts back onto the rectangular connector
in the same order and orientation as they were in when you removed them.

11) Put the set of wires between the microswitch-holding fork, and put
the microswitch back into the fork, the way it was when you removed it.

12) Put the strain relief back into the top of the mouse, put the mouse
back together, and put the screws back in.

This fixed my mouse; it may fix yours if it quits working, since a likely
point of failure is the cable where it goes into the strain relief on
the mouse...
-- 
UUCP: Ofc:  jer@peora.UUCP  Home: jer@jerpc.CCC.UUCP  CCC DNS: peora, pesnta
  US Mail:  MS 795; CONCURRENT Computer Corp. SDC; (A Perkin-Elmer Company)
	    2486 Sand Lake Road, Orlando, FL 32809-7642

	"Oh, is he your friend?  Ask him his name!"

jer@peora.UUCP (J. Eric Roskos) (01/10/86)

Since I posted the above referenced article, I've gotten a couple of letters
that say, "thank you for the instructions, but what does the repair fix?"
I forgot to say that... the repair is for a broken wire in the mouse cable
where it enters the mouse.  The symptom is no cursor motion along one axis,
or no motion at all along any axis, or no detection of button presses,
especially if the problem is intermittent.
-- 
UUCP: Ofc:  jer@peora.UUCP  Home: jer@jerpc.CCC.UUCP  CCC DNS: peora, pesnta
  US Mail:  MS 795; CONCURRENT Computer Corp. SDC; (A Perkin-Elmer Company)
	    2486 Sand Lake Road, Orlando, FL 32809-7642

	"A people without history is not redeemed from time,
	 For history is a pattern of timeless moments." --TSE