Reconnecting lots of fine leads ...

[Hamad bin Turki Salami]

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.

 

[Arfa Daily]

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

 

[Dave D]

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.

If you're not experienced at this sort of work, take it to someone who is.
Such an expensive item is not the best place to learn such skills! If any
tracks are damaged you're looking at a new system board, but if it's simply
a case of resoldering, try to find somone who's experienced with board-level
laptop repairs and get them to do it. It should be much cheaper than $600.

Dave

 

[Hamad bin Turki Salami]

"Hamad bin Turki Salami" <[email protected]> wrote in

<snip>

Well, given my skills, carrying this out was like a 400 lb man running a
marathon. I am astonished, but I actually finished and it fixed the
laptop.

The scariest part of this was seeing all the excess solder after soldering
the connector back on the board. The pins are only 1/2 a millimeter apart
and I made quite a mess of it. Probably a fourth or a third of the pairs
of adjacent pins were shorted initially. It took me quite a while to wick
up that solder.

Thanks a lot for that advice.

 

[Arfa Daily]

<snip>

Well, given my skills, carrying this out was like a 400 lb man running a
marathon. I am astonished, but I actually finished and it fixed the
laptop.

The scariest part of this was seeing all the excess solder after soldering
the connector back on the board. The pins are only 1/2 a millimeter apart
and I made quite a mess of it. Probably a fourth or a third of the pairs
of adjacent pins were shorted initially. It took me quite a while to wick
up that solder.

Thanks a lot for that advice.

Glad it worked out for you. As with a lot of these things, the main
ingredient is confidence ! Well done.

Arfa