"Grant" wrote in message
...
On Thu, 29 Jul 2010 15:17:56 +0100, "Ian P" wrote:

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.

I feel for you, it's a serious oops moment to recover from.

Contact Sony for an idea of cost of fix, so you can place importance
of fixing yourself in your mind? If you can afford the fix at least
there's a way out.

You've got stuff to practice with, but I can't see how you're going to
reliably connect to that fine pitch. Are there accessible places where
the cut tracks get wider? Do the cut tracks terminate to accessible
places where you can create another, separate cable to bridge the
breaks?

IOW, sidestep trying to repair the damage by creating an alternate
circuit.

Seems to me it's a cable replacement, but that could be sub-assembly
replacement if the flex also gets glued in place to some smaller parts.

Take it easy, it is not a rush job.

Grant.

The subassembly in question is the lens. Parts of the cable are wrapped
round and glued to the lens body, and the only way to access it is to
completely dismantle the bulk of the camera, more or less reversing the
original manufacturers assembly procedure.

Ian