"Ian P" wrote in message
...
In the course of doing some modifications to a very expensive Sony 3 chip
HD camcorder I have accidentally cut through 3 tracks on the edge of a
mylar? flexible cable. On the good side the damage is very accessible but
the bad bit is the tracks are only 0.1mm wide on a 0.2mm pitch! Ideally
one would just replace the flex pcb but in practice that would involve
dismantling the camera and lens to get to all the places the pcb branches
out to, and in some places it actually goes into the lens mechanism
itself.

I am considering abrading off the top mylar coating to expose the copper
then bridging the breaks with some very narrow pitch zebra strip. My other
idea is to make my own miniature insulation displacement/piercing
connector using a stack of razor blade bits sandwiched with insulation
layers.

The last option would be to use wire links and solder but I think this
could only be done with some sort of mechanical micropositioning rig in
view of the small sizes involved.

I would be interested to hear any thoughts or experiences if anyone has
any.

Cheers



Ian



Based on my experience of trying to repair accidental damage to flexiprints
(yes, it happens to us all no matter how long we've been in the game and how
experienced we are !) I think that you are going to struggle to get a fix on
one of that tiny pitch. I have had plenty of success with abrading and
soldering ones of a slightly greater pitch, doing it with a tiny
needle-point soldering tip and under a microscope, and using a single strand
from superflex instrument cable, such as is used for better quality meter
leads, for instance.

I don't know whether this is a commercial job, or one for a friend, or maybe
even for yourself, but before you commit to any strategy that's going to
waste a lot of time, and end up with no fix at the end of it anyway, the job
would probably stand being left for a day or two, before revisiting it with
a clear head, to look at how hard replacing the flexiprint would *really*
be. I've often found that things that look as though they are going to be a
copper-bottomed-gold-plated bitch to do, are actually not so bad, when
looked at again after you've calmed down, and forced a degree of 'san fairy
ann' into your head over it. If you have a copy of the service manual or can
obtain one, a look at the parts list will tell you if replacement is even an
option (if you're really unlucky it might be an integral part of the lens
assembly) and if it is available, a look at the exploded view diagram, would
be helpful to determine how many 'hidden' branches the flexiprint has, and
where they go.

I really feel for you on this one. I've been there many times over the years
....

Good luck with it, and please post back, and let us know how you get on with
it :-\

Arfa