Francis McGrath wrote:
I want to thank everyone for posting. I want to make sure I
understand what everyone is saying. There are 2 "wires" with little
teeth. Each wire looks like:

____________________
| | | | | | | | | | | |

It looks like I damaged some teeth, but not the main part of the
wire. Yet it's still not sending signal. Does every tooth have to be
there?

Probably not, especially if this part isn't under any keys. Just to
eliminate the more insane possibilities, can you confirm that this cable
is only connected at one end?


Something I else I'm wondering, since the damage is near the end of
the cable, could I just cut off the damaged portion and reattach the
connector? I have enough slack for this. If I try to remove the
connector, it will probably ruin it, won't it? Also, I don't know how
the ribbon cable hooks to the connector. Any thoughts?


If you powered it on with the screw through the cable, its possible you
damaged the circuit that this sensor connects to. Its also possible you
have a short circuit in the cable due to the damage, but I don't think
so looking at the photo. Is there any evidence of damage to the blue
connector or the mating socket caused by the cable getting pulled as the
screw went through it?

Its likely the contacts on the cable were crimped in place and then the
blue plastic was either moulded round it or otherwise bonded. I wouldn't
try dismantling it without a quote for a replacement in front of me. If
it is a capacitive sensor, shortening it by more than a very small
percentage of the total cable length may put the circuit out of
adjustment and prevent it working anyway.

Check the resistance across the two contact pins on the cable with it
disconnected from the board. If my suspicion that its a capacitive
sensor is correct, the resistance should be higher than a good
multimeter can measure. In that case, connect a capacitance meter, and
see if the capacitance changes noticeably when a small metal object
(e.g. a coin taped to a biro to let you move it without getting your
hands near the circuit) is placed against the cable surface. You will
probably only get a change of a few picofarads. Try either side of the
damage.

I think that it probably calibrates the sensor when it's switched on and
if you allow the cable to move while you are testing the complete unit
it may go out of adjustment and so not work. Did you try it out with the
lid *ON* (you don't need to put all the screws back in)?

Also what was the fault or reason that made you open it to start with?

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
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