FPC, Everywhere!
FPC connectors can be fiddley and troublesome, and a dodgy connection is more often than not the problem behind non-functional or quirky touchscreens. This guide should help you make absolutely sure that all your cables are properly seated.
Main Display FPC Connector
The big, wide flat ribbon on the Touchscreen display assembly is the main connector for the display. It needs to be connected underneath the driver board. This one tends to go fairly smoothly, but these tips will help you get it right, or check your existing connection is sound.
The easiest way to do this is to place the Touchscreen flat on a table with the flat flex connector facing away from you and pick up the driver board with the underside facing you and the FPC slot facing away.
Then use your thumbnail to pop the little black clip loose from the FPC connector. It shouldn't come out completely, but it should slide out slightly.
- Gently slide the flat flex cable over the surface of the driver board with a thumb, toward the slot. Let it lift slightly away as the FPC connector has a little ridge it'll bump into otherwise.
- Firmly push the flat flex cable into the FPC connector. Let it flex slightly so you're absolutely sure it's firmly in place.
- With your spare thumbnail close the FPC connector securely and make sure it's tightly shut.
Touch Sensor FPC Connector
The tiny little touch FPC connector is trickier, and tends to cause the most problems. Almost all touchscreen failures that I've seen have simply been down to it not being plugged in properly.
This time you will need to very gently slide out the tiny little restraining clip. It shouldn't come all the way out, but it's extremely delicate so it might do. If it does, don't worry, push it gently back into place.
- Again, slide the flat flex cable over the surface of the driver board, letting it lift ever so slightly away to clear the ridge at the bottom of the FPC connector.
- Use your other thumb to gently close the connector.
- Make sure the cable is plugged right in, the part where it gets wider should be right at the edge of the driver board, and the clip is fully closed.
Pi FPC Connector
Last but not least is the ribbon cable that connects to the Pi. This one is much easier to hook up.
- With the connector on the driver board open, position the flat flex cable into the slot above the black retaining clip. Make sure the metal contacts are facing upwards, out away from the driver board.
- Slide the cable firmly into place.
- Close the plastic clip firmly to secure the flat flex cable.
The connection on the Pi side is much the same, and really hard to get wrong.