Is anyone aware of how to repair a ribbon cable for an lcd panel?
I'm a mech. E. at a major engineering college, and I could probably weasle my way into getting some of my EE friends to help me if I need to. Any ideas on whats involved?
I'm a mech. E. at a major engineering college, and I could probably weasle my way into getting some of my EE friends to help me if I need to. Any ideas on whats involved?
I recently broke a ribon cable on a 14.1 inch phillipsLG lcd out of a compaq laptop.
It was a short ribbon attaching the main, and daughter boards together.
First i removed the old ribbon cable(soldering iron, heat and remove) and next I soldered thin SOLID copper wires between the pads on both boards.
The pads on my controllers were big enough to get a good solid connection.. It took a fair amount of work, and a blown fuse to get the wires seperated enough and solid enough for use, but is fine now.
find the best solderer you know to do the job, it is tricky buisness, and inspect all wires THOUROUGHLY before powering up.
WARNING: Cover the LCP with something while soldering, melting it after all that work would suck
It was a short ribbon attaching the main, and daughter boards together.
First i removed the old ribbon cable(soldering iron, heat and remove) and next I soldered thin SOLID copper wires between the pads on both boards.
The pads on my controllers were big enough to get a good solid connection.. It took a fair amount of work, and a blown fuse to get the wires seperated enough and solid enough for use, but is fine now.
find the best solderer you know to do the job, it is tricky buisness, and inspect all wires THOUROUGHLY before powering up.
WARNING: Cover the LCP with something while soldering, melting it after all that work would suck
More info
I made the somewhat stupid assumption that all cable breaks would be the same, but while thinking about the problem last night I realized some more info would probably help, so here it is...
the cable itself is intact, it broke cleanly off of the circuit board. The contacts on the board are gold, and it appears they were at no time soldered. The board side pitch is slightly less than one (~.8) mm (measured by measuring # pins/overall length) so, assuming I can hit it with a soldering iron I should be ok. Can you bond normal silver bearing solder to gold contacts? If so, the cable itself is coated with plastic on one side, so, I (think) I would have to shave the plastic off to get a side to actually solder the contacts from.
Option two, which I have considered, is soldering a few extremely small gage wires to the contacts, acting as a sort of extension, also giving me access to the contact side of the cable, making soldering easier. The fact that the traces are gold, however, makes me think this might be unadvisable, since resistance might be a major issue. Any thoughts?
I made the somewhat stupid assumption that all cable breaks would be the same, but while thinking about the problem last night I realized some more info would probably help, so here it is...
the cable itself is intact, it broke cleanly off of the circuit board. The contacts on the board are gold, and it appears they were at no time soldered. The board side pitch is slightly less than one (~.8) mm (measured by measuring # pins/overall length) so, assuming I can hit it with a soldering iron I should be ok. Can you bond normal silver bearing solder to gold contacts? If so, the cable itself is coated with plastic on one side, so, I (think) I would have to shave the plastic off to get a side to actually solder the contacts from.
Option two, which I have considered, is soldering a few extremely small gage wires to the contacts, acting as a sort of extension, also giving me access to the contact side of the cable, making soldering easier. The fact that the traces are gold, however, makes me think this might be unadvisable, since resistance might be a major issue. Any thoughts?
Are you sure the gold isnt copper?
If they were not soldered in place i have no idea what the adhesion method would be, and i doubt soldering onto gold would work too well. Gold is normally only used in things that small which have connection of friction (connectors) not solderable pads as far as i know
.mike
If they were not soldered in place i have no idea what the adhesion method would be, and i doubt soldering onto gold would work too well. Gold is normally only used in things that small which have connection of friction (connectors) not solderable pads as far as i know
.mike
They're definately gold. I'm honestly not sure how they were connected... its possible to solder gold (jewelers do it all the time, for instance) but I think gold solder is very expensive...
Just looking around today I was able to find some references to using electrical solder to bond gold, some of which indicated it could be difficult in some situations, and recommended use of a silver tracing pen.
I also found a site describing repair procedures for surface bonded circuits, which, in the case of gold contacts, seems to involve a lot of chemicals and plating... http://www.circuittechctr.com/index.shtml
For the purposes of this area, I'd be willing to guess the contact bonding method might have been excessive, since most transistors have voltage tolerance ranges well within the slight variation in voltage which could be produced by resistance in normal, silver bearing electrical solder.
The contacts on the cable, by the way, appear to be made of or covered in a grey, malleable metal that shines brightly if I scratch it using mechanical means (ie, the edge of an x-acto knife), which might be solder.
I'll play around with it in the near future and let you guys know how things go.
Just looking around today I was able to find some references to using electrical solder to bond gold, some of which indicated it could be difficult in some situations, and recommended use of a silver tracing pen.
I also found a site describing repair procedures for surface bonded circuits, which, in the case of gold contacts, seems to involve a lot of chemicals and plating... http://www.circuittechctr.com/index.shtml
For the purposes of this area, I'd be willing to guess the contact bonding method might have been excessive, since most transistors have voltage tolerance ranges well within the slight variation in voltage which could be produced by resistance in normal, silver bearing electrical solder.
The contacts on the cable, by the way, appear to be made of or covered in a grey, malleable metal that shines brightly if I scratch it using mechanical means (ie, the edge of an x-acto knife), which might be solder.
I'll play around with it in the near future and let you guys know how things go.
soldering to gold
Is done all the time, with standard rosin-core solder. Lots of components have gold plating on their leads.
Your cable may have been soldered to begin with, just not very well. There are plastics with higher melting points than solder. There are also conductive glues. That is how the FFC cables are attached to the LCD panel's traces.
Find an electronics tech who is an expert at modifying PC boards, and show him or her your board.
Is done all the time, with standard rosin-core solder. Lots of components have gold plating on their leads.
Your cable may have been soldered to begin with, just not very well. There are plastics with higher melting points than solder. There are also conductive glues. That is how the FFC cables are attached to the LCD panel's traces.
Find an electronics tech who is an expert at modifying PC boards, and show him or her your board.
Don't try soldering it unless you are sure you have broken contacts.
If you're talking about those paper thin ribbon cables, and you have exposed gold contacts on the cable, then it may have simply pulled out of the plastic block that held it.
The block must have some kind of latching mechanism on it, the ones I've seen are 2 very tiny tabs on opposite sides of the plastic block that pull out towards one of the long sides. Once you hav epulled out the tabs, you should be able to simply slip the ribbon cable back into the block and push the tabs back.
Hopefully I've understood your problem and helped.
If you're talking about those paper thin ribbon cables, and you have exposed gold contacts on the cable, then it may have simply pulled out of the plastic block that held it.
The block must have some kind of latching mechanism on it, the ones I've seen are 2 very tiny tabs on opposite sides of the plastic block that pull out towards one of the long sides. Once you hav epulled out the tabs, you should be able to simply slip the ribbon cable back into the block and push the tabs back.
Hopefully I've understood your problem and helped.
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