"Hamad bin Turki Salami" wrote in
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I have a laptop (an Apple Powerbook G4 17 inch) where the keyboard is not
working right. It seems the owner dropped it and the connector that
accepts the ribbon cable from the keyboard has come a little loose. The
connector has 40 very fine leads, closely spaced, that are surface mounted
to the motherboard (or should be).

Reconnecting this thing looks like a real challenge. The leads are too
fine and too closely spaced for my finest point soldering iron, and
I think it would take superman to apply new solder to each of those
leads without shorting them together.

The only thing I can think of right now is to just apply heat and
pressure to the leads, in the hope that there's enough solder still
under them to reattach them.

Replacing the motherboard is a very expensive option (about $600), and
I'm not keen on destroying the motherboard attempting to reconnect
the keyboard connector, since the laptop is at least working right now
with a USB keyboard attached.

Any advice very much appreciated.

Assuming that the joints have just fractured, and the underlying print has
not detached from the pcb substrate, then you would deal with refixing them
in the same way as you would any s.m. high pin density chip. The trick is
not to worry about the pins shorting together during the resoldering
operation.

You should first use a good quality solder wick to remove existing solder
from the tops of the connector pins. Then, treat the connector pins to a
coat of liquid flux. Next add solder to the pins, using the finest gauge of
solder that you have, and the finest iron tip. Always pull the iron tip back
away from the connector whilst the solder is molten. This, plus the action
of the liquid flux in assisting good joint wetting and hence capillary draw
of the solder into the joint, will go a long way to stopping the solder
running across multiple pins, but you will probably still get some cases. DO
NOT worry about these at the time, just finish the job.

Finally, check carefully with a strong magnifier, to locate any solder blobs
between pins, and remove these by quick use of clean good quality solder
wick, applied to the vertical faces of the shorted pins. When you are happy
that the blob has gone, clean up the flux residue using a proprietry flux
remover and an old toothbrush ( try it out on the toothbrush first - some
cheap ones are made from plastic that disintegrates when the flux remover is
applied ).

I would suggest that you practice first on a scrap board, but if you can
solder in the first place, and use the right kit, you will find it an awful
lot easier to do than you imagine.

Arfa