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The switches in the presenter (clicker) depicted below normally close when firmly pressed, by giving way and making contact with a positive feeling and sound. However, the bottom-right switch appears to close at a mere touch, so much so that when the switch above it is pressed, the faulty switch also closes. In presentations this is a problem, because when I press page-down (the top-right switch) the presentation disappears (due to the action of the bottom-right switch). Is there a way I can fix the faulty switch? I tried lifting the plastic sheet that covers them, and apparently the metallic tops of the switches are attached to it rather than soldered on the PCB.

enter image description here

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    \$\begingroup\$ Is this something you designed or something you just have/use? This detail is important because if it's not your design then the question will be considered as off-topic: Questions on the repair of consumer electronics, appliances, or other devices must involve specific troubleshooting steps and demonstrate a good understanding of the underlying design of the device being repaired. If this is your own design then things may change. But you need to post the schematics and PCB layout. And also this might be mechanical problem, so these details are needed. \$\endgroup\$
    – Rohat Kılıç
    Dec 11, 2021 at 9:16
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    \$\begingroup\$ It's not my design, but I troubleshooted the device to find out why pressing one external button had the effect of pressing another. Regarding a fix, the answer by @Maple seems to be on the mark, and I will try it right now. \$\endgroup\$
    – Diomidis Spinellis
    Dec 11, 2021 at 9:43
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    \$\begingroup\$ @rohat what part of your quote says that only a design by op would be on topic? \$\endgroup\$
    – Passerby
    Dec 11, 2021 at 10:38
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    \$\begingroup\$ I think he probably means that it may be considered off-topic @Passerby \$\endgroup\$
    – Andy aka
    Dec 11, 2021 at 11:20
  • \$\begingroup\$ @Passerby I meant it may be considered off-topic because it looked like a repair-related question to me. And I thought the last part of my comment completes this. \$\endgroup\$
    – Rohat Kılıç
    Dec 11, 2021 at 14:03

1 Answer 1

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Those flexible contacts are supposed to be centered on their places. These are called "tactile membrane switches", by the way.

It seems that metal switch domes were attached carelessly misaligned (shifted down and to the left), but the one in bottom-right corner is shifted more than others. It practically touches middle contact with its top-right "leg".

enter image description here

Peel the tape with domes on it. Clean those golden circles and dots in the middle of them with an alcohol. Align domes properly centered on the circles and it should be OK.

In cheap devices the domes usually held in place with a piece of sticky tape, so if it does not stick back nicely, you can also replace the tape. You can use pretty much any scotch tape or whatever non-conductive sticky tape you have at hand.

The easiest way to do it is put tape upside-down first, then use contact circles as guides for arranging domes on the tape. When everything is in place, flip the tape, do a final alignment and press it down.

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    \$\begingroup\$ All domes appeared to be misaligned toward the bottom-left. I peeled the tape together with the domes, cleaned the golden contact areas, and carefully placed the tape back aligning the domes on the contact areas. The device worked like a charm. Thanks! \$\endgroup\$
    – Diomidis Spinellis
    Dec 11, 2021 at 10:36
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    \$\begingroup\$ Packing tape would be better than scotch/ magic tape. \$\endgroup\$
    – Passerby
    Dec 11, 2021 at 10:39
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    \$\begingroup\$ Nice work on the image - what soft did you use to align the lower middle dome? \$\endgroup\$
    – Andy aka
    Dec 11, 2021 at 11:22
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    \$\begingroup\$ @Andyaka 15 years old Photoshop \$\endgroup\$
    – Maple
    Dec 11, 2021 at 18:45
  • \$\begingroup\$ Good man. Old soft that still cuts the mustard. \$\endgroup\$
    – Andy aka
    Dec 11, 2021 at 19:08

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