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I have a handheld radio with an LCD display. Due to time and climate, the rubber in the elastomeric connector seems to have gone hard and as a result the LCD shows the usual signs of failure, letters and symbols blinking off and disappearing, etc.

I've looked hard and long for a matching replacement, but the only elastomeric connectors I can find online are of a very few, very specific sizes, and of course none of them match.

Can I just buy a larger one and cut it down? If so, how do I best do this, just a very sharp knife or do I need something else? Or did I miss a source where I can get them in more sizes? I can't even find one in the right thickness.

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    \$\begingroup\$ Cutting it to length should be OK with a sharp knife. Cutting it down in height would require extreme precision or the low points won't make good contact, but hopefully you won't need to do that. \$\endgroup\$ – Brian Drummond May 7 '16 at 13:31
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Zebra strips are most often custom made to size to suit the enclosure design requirements of a product designer. This is why it can be hard to find general purpose replacements.

Using the following drawing as a reference:

enter image description here

Dimension H between the circuit board and the LCD glass is the most critical dimension. Proper operation normally requires the material to be slightly compressed in this dimension for the carbon material in the elastomeric sandwiches to make contact with the glass and PC board conductors. It is not really feasible to cut the material in the H dimension due to the high tolerance parallelism required of the adjacent surfaces.

It is no problem adjusting the L dimension by purchasing a longer strip and cutting it down.

The T dimension can be critical since if it is too far out of the original size it can affect how material compression works in the H dimension. It may be feasible to trim a strip with a bigger T dimension to a smaller one but I can say from experience that trying to cut silicone elastomeric materials can be very difficult using a blade in a progressive cutting action.

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When connecting LCD glass to a PCB, zebra connectors need to be compressed about 15%, when tightened down. It is possible to cut down these elastomers, but start with new connectors. These are cut at the factory using steel rule die cutting. It's possible to make accurate cuts by making a simple plexiglass fixture to hold the zebra tightly. You need to create a straight edge that keeps a safety razor blade straight up and down when cutting the zebra. We stock 1000's of zebras, but we only have ten different sizes.

In a fixture, a new safety razor works a lot like a steel rule die.

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