Keyboard Destroyed by Dog

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My friend's dog chewed up the USB cable on his Apple keyboard.  He is
wondering how easy (hard) it wud be to repair it?



Re: Keyboard Destroyed by Dog wrote:
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Give the dog a soldering iron, and make him
repair it :-)

It should be easy.

If you had written down the keyboard model number,
that would have been a help. I've given you a rundown
on my keyboard, just for the hell of it.


M7803 keyboard ("Apple Pro Keyboard")
Beige with faint black lettering (poor contrast)
Includes numeric keypad on right side.

1) Flip keyboard onto keys.

2) Using 0.050" hex key, remove the two screws near the
    USB connectors, and the two screws located on the side
    below them. Keep track of the screws. One on the left,
    is a shorter screw than the other three (I suspect an
    assembly mistake at the factory).

3) Flip keyboard on its back, so you can now see the keys.

4) The top transparent cover, is a compression fit. You can
    pry it apart with your fingers, a bit at a time. As compression
    fits go, it's not the worst I've dealt with. You can actually
    get it apart without snapping the plastic.

5) With top cover removed, look near top center, where the cable
    enters the keyboard. There are two Phillips (cross shaped)
    screws that fasten the strain relief plastic block to the
    bottom. Use your smaller Phillips head set, to find a
    screwdriver to fit. I have jewelers screwdrivers, but used
    a set of Fuller jewelers-like screwdrivers (handle with
    rod-shaped screwdriver bodies with heads on either end).

    While you're in that area, and have removed the two screws,
    you'll see something "evil". There is an anti-tampering
    screw located where you can see it. The plastic "label"
    on the bottom of the keyboard (where the M7803 is printed),
    covers that screw. Keep this in mind.

6) With the keyboard still upright, you'll notice three plastic
    "dimples" on the base of the keyboard tray. They're located along
    the horizontal center line. Shine a light up through the
    dimple. You'll see light appear under one of the keycaps.
    There is a screw in each dimple (removes from the top) :-)

    You'll need to pop off three key caps. "Caps Lock" key, the
    colon ":" key for the center screw, and the numeric pad
    "6" key. I used two of my smallest hex keys, and levered
    on diagonal corners of the key, using depressed keys on
    either side of the diagonal line for support. The key caps
    come off without too much trouble. To return them to their
    original location, make sure the center part is mated, then
    "rock" from side to side, until first the left and then the
    right tab slides into place. Pushing straight down would require
    twice the force.

7) With the three keycaps removed, get out your Phillips head
    screwdriver again, and remove the three screws. The center
    screw is shorter than the left and right ones.

8) OK, now the bottom cover is loose, but one screw remains.
    You can again use your flashlight. With the keyboard turned over
    onto the keycaps (and being careful not to tug on the cable too
    much, shine a light up through the keyboard near the cable
    strain relief block. The plastic holding the screw up there,
    will cast a circular shadow on the very nice looking Apple label
    on the bottom of the keyboard. That shadow shows you where to
    access the screw.

    With your Phillips screwdriver, and not trying to make too much of
    a mess, stab the screwdriver dead center into the shadow area. If
    you're good, the Philips screwdriver will mate with the Philips
    screw underneath (it's about half an inch down). When you unscrew
    it, there is no need to pull the screw - leave it resting underneath
    the label, so it cannot escape from its jail cell. Later, stab the
    screwdriver into that nice neat hole you made, and you can fasten
    it again. Since there is now a hole, Apple staff can see you've
    tampered with the keyboard. The warranty is void (that's why they
    do anti-tampering screws).

9) Turn the keyboard over. Once you remove the lower plastic cover,
    the keyboard components won't have as much mechanical support,
    so don't go flipping it around too much from this point onwards.
    You can put the bottom cover back in place temporarily, if you
    need to lend it mechanical support again.

    With bottom cover removed, you should see a metal cover over the PCB.
    The cable is soldered into place. The cable has five wires. Unexpectedly,
    it has a shield, as well as +5V, D+, D-, GND wires. They gathered up
    a hunk of shield foil and soldered a black wire to it (that's tricky
    to do, by the way, because you could melt the wires underneath). On
    the end of the black wire, is a grounding screw. That's how the shield
    gets electrically connected to the keyboard.

    The other four wires are soldered to the PCB.

    I didn't disassemble it any more than that.

10) When making a new cable, you'll first need a cable of the correct
     outer diameter. If you chop up any old USB extension cord, it'll be
     too big. The strain relief block only has room for a certain diameter
     of cable. So that'll be a challenge. If Apple were to make a replacement
     cable, complete with soldered-in-place shield wire, that would be
     a great help. That cable is a bit special, in that in my experience, it
     takes more abuse than your average cheap cable from the store. The wire
     seems to be a bit more flexible than some of the other cables I have
     here. I expect it's the outer finish that is more flexible.

     I didn't look at the solder side, to see if they did anything "magic".
     I didn't want to break anything :-)

Gave me a great opportunity to remove cracker crumbs and dust :-)
And all those inevitable coffee stains.

For the three screws that hold the bottom cover to the keyboard
assembly, don't over-torque them. The center screw in particular,
it's hard to feel whether you've got it tight enough. The
screw is short, and I expect mine is close to stripped. The
outer ones are OK. The rest of the screws didn't seem to be a problem.

It helps if your tools (hex key and screwdriver) are magnetized,
as otherwise it'll take more tries to get the screws into place.


One other Apple keyboard I worked on (Extended II) model, it
was a bitch. They used steel rivets on that thing, so you
can't take it apart. I wasn't able to clean that one
very well, after a coffee spill, and three keys got stuck
on it. Even with a ten minute rinse, and a two day dry
cycle with mild heat. At least the so-called "Pro" keyboard,
there were no rivets.


Re: Keyboard Destroyed by Dog

On 02/23/2015 05:50 PM, wrote:
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Just 4 wires

a simple fix

Re: Keyboard Destroyed by Dog

philo wrote:
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Actually, on my Apple keyboard with USB, it's five wires.
(The fifth wire is shield, and likely done so it
would be possible to do USB2 passthru, using the
two connectors on either side of the keyboard.)

At one time, keyboard USB cables, were thinner, and
were done with just four wires, and no shield foil.
They could do this, because the hardware negotiated
to the slowest speed possible (not even 12Mbit/sec,
slower than that).

The signal integrity without a shield just isn't
there for stuff like 480Mbit/sec transmission.

By Apple putting the shield foil and wire there,
it means if you stick a USB2 device on the spare
connector on the end of the keyboard (intended to
take the Apple mouse), the wiring is USB2 rated.


Re: Keyboard Destroyed by Dog

On 02/23/2015 11:27 PM, Paul wrote:
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Yep I should have mentioned that.

People are always giving me their old stuff and a few years back I got  
an Apple keyboard that had a cut off cord. Since I did have a use for it  
I just spliced on a new cord was no big deal though it may not  
look pretty

Re: Keyboard Destroyed by Dog

Quoted text here. Click to load it

I have emailed your responses to my friend this AM.



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