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Carbon track ribbon cable end, repairing

A

Ancient_Hacker

Jan 1, 1970
0
Hi, I have a small LCD display where the edge has a 60-track ribbon
cable going to the motherboard. The cable is clear plastic with very
thin carbon tracks. The end going to the PC board has gone
intermittent, so I pulled it off. Apparently it was glued on with some
gray goop.

The carbon tracks on the end of the cable have mostly pulled off the
plastic. I could cut off the bad end as there's about 1/4 inch of
slack in the cable BUT:

(1) There's some beige painted-on insulation over the carbon. It
comes off with acetone, but so do the carbon tracks! How do I get the
beige insulation off without hurting the delicate carbon underneath?

(2) What do I use to glue the cable back on? Or should I fashion a
clamp?


Help!
 
N

n cook

Jan 1, 1970
0
Ancient_Hacker said:
Hi, I have a small LCD display where the edge has a 60-track ribbon
cable going to the motherboard. The cable is clear plastic with very
thin carbon tracks. The end going to the PC board has gone
intermittent, so I pulled it off. Apparently it was glued on with some
gray goop.

The carbon tracks on the end of the cable have mostly pulled off the
plastic. I could cut off the bad end as there's about 1/4 inch of
slack in the cable BUT:

(1) There's some beige painted-on insulation over the carbon. It
comes off with acetone, but so do the carbon tracks! How do I get the
beige insulation off without hurting the delicate carbon underneath?

(2) What do I use to glue the cable back on? Or should I fashion a
clamp?


Help!

How are the conductors of the ribbon connected to the conductive lands on
the LCD glass ?
 
S

spudnuty

Jan 1, 1970
0
I would also be interested in a solution to this problem. I have a
Toshiba laptop in my "to be repaired pile" and the same thing has
happened to the LCD cable. It was glued to the LCD glass and the glue
has aged and become brittle so that the connection is completely off.
Richard
 
N

n cook

Jan 1, 1970
0
spudnuty said:
I would also be interested in a solution to this problem. I have a
Toshiba laptop in my "to be repaired pile" and the same thing has
happened to the LCD cable. It was glued to the LCD glass and the glue
has aged and become brittle so that the connection is completely off.
Richard

n said:
How are the conductors of the ribbon connected to the conductive lands on
the LCD glass ?

As far as flexible ribbon replacement I usually plait up fine 40swg
enamelled/magnet copper wire into a braid, in this case 6,7,7 wires plaited,
cut into 3 and then those 3 plaited together . This is very flexible and
seems long lasting. Identify the order of conductors , bypass the ribbon
connector at the pcb end and solder direct to the pcb. The problem is the
LCD end. If it is proper metal in the ribbon it is possible to cut close to
the LCD it may be pssible then to grind back the covering to give some land
pads.
How to remove the glue without removing the conductive deposition lands on
the LCD edge. I would try squashing each stripped wire end in steel plates,
risking work hardening but as conductive glued/painted to each land and then
overall glued that should be ok, any inter-trace overpaint/shorts cut back
before total curing. It is the safe removal of existing LCD contacts that is
the problem. I've never tried the LCD part of such a repair but would very
localised heat like SM re-work hot air gun work to release without
destroying the conductive glass coating or crack the glass ?
 
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