Hello!

I have LC2 that doesn't respond to the touch function and I decided to fix it. First I tested the sensi-touch field by touching the PCB pad where the small rubber tube fits. It was working. I checked the faulty dome on another (working LC2) and it was not working.

There were 2 issues:

1.  The rubber tube that connects the PCB to the dome was missing
2.  Even with the tube from another LC2 the dome was not making contact. The problem was that the trace from the spider web in the center of the dome to the edge was broken. You can check the trace with an ohmmeter. It should have a very small resistance (about 8-10 ohms). Take care not to scratch the paint on the dome.

The FIX:
1. I replaced the tube with a small rubber connector from an LCD salvaged from an old desk calculator (the rubber strip that connects the LCD to the PCB).
2. I repainted the trace on the dome that connects the spider web to the edge of the dome with Conduction Silver L100. The silver paint cures in about 20 minutes. I needed 2 coats of paint to get the dome working again.

http://www.kemo-electronic.com/en/zubehoer/l100/index.htm

Hope this helps!

Regards,
Andrei

Great job Andrei,

in the past I also repaired 2 of mine LC2 units. It had cracks in the spider web. I replaced it with a strip of aluminum foil. It was attached with some glue from the top of the dome to the connection point of the rubber tube. I made the strip smaller where it makes contact with the rubber tube.

This is also a method to repair the touch function.

Piet