Repair infrared soldered connection?

Sep 30, 2007 8 Replies

I have a cordless phone with a LCD that has some of the characters missing. I was able to determine it is a poor connection at the point which a flex ribbon cable is attached to the PWB. That connection is apparently soldered with the infrared technique. Does anyone have any ideas on how such a connection could be repaired with common electronic repair tools?



Obviously it can be done with the tools used to assemble the circuit when made, but not many people have such tools in their homes. Thanks.


You need the proper tools. Call Sony or one of their service centres and see if they will do it for you. It is very possible that they only buy and replace the parts only.

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JANA _____

Obviously it can be done with the tools used to assemble the circuit when made, but not many people have such tools in their homes. Thanks.

Can you bodge something in the way of mechanically compressing the contacts using wrap-around cable tie/s and "folding wedges" from wooden clothes pegs ?

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Or, I was going to suggest silver (conductive) Epoxy.

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We must have gone to the same school. I wedged into the area of the connection a piece of hard rubber that will press against the area when the phone is closed. It is working, but I wish there was a permanent fix. With so many on this newsgroup fixing so many things, I thought I would ask if anyone had fixed such a connection. Thanks for the reply.

Conductive epoxy? Do you have a brand or type you have used?

This is one of those cases where they had trouble making good connections under ideal factory conditions, so doing better at home is unlikely. I hate this design because it's basically non-serviceable. I've had some luck heating the area that has the bad connection by pressing a soldering iron against it. You have to be careful that the tip isn't hot enough to melt the plastic (use a variable temperature soldering iron). Even after that, installing something to apply constant pressure is a good idea. Andy Cuffe

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I'm a bit unclear about this. LCDs are often connected to the PCB with a conductive-rubber band. It seems odd that one would be soldered in.

This one uses a flex cable of the ribbon type. It appears that the conductors are soldered with solder paste using the IR heating technique. The problem in heating the connection again is the plastic the conductor is mounted on will be damaged unless you use a low temp iron or the original IR process of heating the solder paste during assembly.

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