Repairing flexible pcb connector track?

[Ian P]

I wouldn't hesitate to do this, but I'd not attempt it whatsoever
without a microscope. Can you borrow one?

Unfortunately I don't have anything other than strong magnifying glasses and
I cannot think of anyone or anywhere I could borrow one from.

In the past I have tried soldering etc whilst looking through a magnifying
glass but have struggled because of only really looking through one eye so
really stereo magnification is what I need.

Ian

 

[bz]

Unfortunately I don't have anything other than strong magnifying glasses
and I cannot think of anyone or anywhere I could borrow one from.

In the past I have tried soldering etc whilst looking through a
magnifying glass but have struggled because of only really looking
through one eye so really stereo magnification is what I need.

Do you have a video camera that can do closeups?
Can you work while watching what you are doing via a monitor?

If you have a piece of similar cable that you can glue along side the cut
one, you might be able to use straight pins to pierce both conductors
simultaneously and then turn the pins into 'rivets' permanently connecting
the broken conductors through the 'bridging' conductor.
Stagger the 'rivets' so they don't short to each other.

You may be able to get some very thin diameter straight pins such as used
for mounting butterflies or from a hobby store, used as nails, etc on small
models. Perhaps even with a copper coating, so that you could touch them
with a bit of solder to 'make things permanent'.

Try it first on some pieces of similar flex from the trash/junk box.

Stagger the pins to give more room to work.

Good luck!

 

[Ian P]

After mulling over all the good guidance and advice I recieved in response
to my original posting I decided which method to use and this evening have
successfully repaired the cut tracks.

I went for the soldered wire jumpers over the breaks, straightforward under
normal circumstances but in this case on a small scale. I bridged four
adjacent tracks using wire 0,05mm (2 thou) diameter taken from super
flexible test lead wire. The tracks were were between 0.1 and 0.15mm wide
and the whole repaired area ended up 0.9mm wide and 4mm long.

With the right equipment, microscope etc I can now see that a repair of this
sort could be done fairly easily, I managed with a strong magnifyng glass
that I fixed in place so I had both hands free. After I fixed the first
jumper I improved my technique and was able to work one handed by using a
longer length of jumper held taught exactly in line with the track by bits
of masking tape at either end. Because of its length its really easy to
position the jumper, I also put a little bit of packing under the ribbon so
that it formed a raised surface to keep the wire in contact with the
previously tinned tracks.

I still have to test the repair but mechanically all the joints are sound
and separated from each other so I'm happy.

Many thanks to all that responded.

Ian

 

[Arfa Daily]

After mulling over all the good guidance and advice I recieved in response
to my original posting I decided which method to use and this evening have
successfully repaired the cut tracks.

I went for the soldered wire jumpers over the breaks, straightforward
under normal circumstances but in this case on a small scale. I bridged
four adjacent tracks using wire 0,05mm (2 thou) diameter taken from super
flexible test lead wire. The tracks were were between 0.1 and 0.15mm wide
and the whole repaired area ended up 0.9mm wide and 4mm long.

With the right equipment, microscope etc I can now see that a repair of
this sort could be done fairly easily, I managed with a strong magnifyng
glass that I fixed in place so I had both hands free. After I fixed the
first jumper I improved my technique and was able to work one handed by
using a longer length of jumper held taught exactly in line with the track
by bits of masking tape at either end. Because of its length its really
easy to position the jumper, I also put a little bit of packing under the
ribbon so that it formed a raised surface to keep the wire in contact with
the previously tinned tracks.

I still have to test the repair but mechanically all the joints are sound
and separated from each other so I'm happy.

Many thanks to all that responded.

Ian

Glad you got a fix ! If the flexiprint doesn't have to bend at the point
where you've repaired it - and I assume that it doesn't as you say that you
have put some strengthening behind it - you might want to coat over the
repair with some clear nail laquer, just to add a bit of 'stay still' to the
wires, and offer a bit of physical protection.

Don't know if you might have a need in the future to do any very fine work
like this again, but if you do, a stereo microscope with built in work lamp
is indispensible. You can pick them up quite cheaply on eBay. Mine came from
Farnell when they had them on offer a few years back. It takes a bit of
getting used to soldering under one, as even the finest tipped iron looks
like a wrought iron poker that the local smithy has just turned out, and the
solder looks like a steel ship hawser, but then even very fine tracks look
like roads, so it's all relative ...

Arfa

 

[Grant]

After mulling over all the good guidance and advice I recieved in response
to my original posting I decided which method to use and this evening have
successfully repaired the cut tracks.

I went for the soldered wire jumpers over the breaks, straightforward under
normal circumstances but in this case on a small scale. I bridged four
adjacent tracks using wire 0,05mm (2 thou) diameter taken from super
flexible test lead wire. The tracks were were between 0.1 and 0.15mm wide
and the whole repaired area ended up 0.9mm wide and 4mm long.

With the right equipment, microscope etc I can now see that a repair of this
sort could be done fairly easily, I managed with a strong magnifyng glass
that I fixed in place so I had both hands free. After I fixed the first
jumper I improved my technique and was able to work one handed by using a
longer length of jumper held taught exactly in line with the track by bits
of masking tape at either end. Because of its length its really easy to
position the jumper, I also put a little bit of packing under the ribbon so
that it formed a raised surface to keep the wire in contact with the
previously tinned tracks.

I still have to test the repair but mechanically all the joints are sound
and separated from each other so I'm happy.

Many thanks to all that responded.

Great news! Even if it not work first time, sounds like you find a good
technique to repeat.

Grant.

 

[William Sommerwerck]

Congratulations! Or should I say "Congratos!"?

 

[Meat Plow]

After mulling over all the good guidance and advice I recieved in
response to my original posting I decided which method to use and this
evening have successfully repaired the cut tracks.

I went for the soldered wire jumpers over the breaks, straightforward
under normal circumstances but in this case on a small scale. I bridged
four adjacent tracks using wire 0,05mm (2 thou) diameter taken from
super flexible test lead wire. The tracks were were between 0.1 and
0.15mm wide and the whole repaired area ended up 0.9mm wide and 4mm
long.

With the right equipment, microscope etc I can now see that a repair of
this sort could be done fairly easily, I managed with a strong magnifyng
glass that I fixed in place so I had both hands free. After I fixed the
first jumper I improved my technique and was able to work one handed by
using a longer length of jumper held taught exactly in line with the
track by bits of masking tape at either end. Because of its length its
really easy to position the jumper, I also put a little bit of packing
under the ribbon so that it formed a raised surface to keep the wire in
contact with the previously tinned tracks.

I still have to test the repair but mechanically all the joints are
sound and separated from each other so I'm happy.

Many thanks to all that responded.

Ian

Get yourself a 25x stereo magnifying visor. It's a good investment.

 

[Rich Webb]

Get yourself a 25x stereo magnifying visor. It's a good investment.

2.5x (5 diopter)?