4.3" LCD screen problem

NETMF & Gadgeteer
1

I got my FEZ Cobra and the 4.3" LCD touchscreen. I followed all the directions in the brochure (I connected it properly, I ran the LCD configuration, and ran the calibration.)

The backlight on the LCD does not appear to be working. I can barely make the text out, but I can see the TouchCalibration program running, but I need to shine a bright light on the LCD screen.

How do I get the backlight working on the LCD screen?

I am not sure if this helps, but I am powering the board from the 5V mini USB client port. Do I need more juice (e.g. 6V external power supply?)

2

You shouldn’t need any extra power. IIRC, the 4.3" screen has a separate ribbon cable for the BL. Is that hooked up correctly?

3

Everything on the expansion board came preassembled. All three cables, besides the one I inserted, look like they are fine. After I saw your reply I took them out and reinserted the three cables and still no backlight.

Would you happen to know which of the three cables is the backlight cable?

4

The thinner cable is for backlight. You can see only traces in it.

5

I do not want to sound rude, but is the cable the right way connected? With the connections to the upper side?

6

he sees some images so it is correct. Maybe he did plug it in backward at first and this is how it got damaged?

7

He said it came preassembled.

8

Thanks for letting me now which cable was the backlight connector. I started to dink around with it and noticed that the plastic “clip”, or whatever you call it, that locks the cable into the expansion board doesn’t appear to be locking in the cable.

I tried pushing the plastic “lock” out, removing the cable, reinserting the cable, then pressing back in the plastic “lock”. It appears maybe the plastic clip/locking thing is defective on the expansion board because the cable is still loose, but looks like it is in there.

By messing around with it and some blue putty I was able to get it into a position that allows the backlight to stay on. I’ll have to think of something else more permanent like tape, super glue, or hot glue.

Any suggestions?

9

It is normal to still see the cable loose.
The lock only apply some pressure on the cable to insure the contact. and it is still easily removable after without unlocking the lock.
But definately, you are not supposed to add any kind of glue on.

All the LCDs and TFT expansions, preassembled or not, are carfully tested before shipping.

10

I’m sure you guys test everything, but I’m telling you the little backlight cable rattles around inside the connector thing and doesn’t stay put all the way in the connector even when the plastic lock is pressed back/closed.

You’re probably right not to use any glue.

I guess I’ll just use tape or the blue tacky putty unless you guys have any other suggestions?

Thanks for all the help. I do appreciate it.

11

Could you post a image of the damaged connector?

12

If you feel that the board has some problem then please send it back and we will happily replace it for you.

By the way, the back-light cable is really fragile and the connector is very tiny too so the cable will never be super tight in there but it should be secure enough that it will always work and will never come out on its own, even with high vibration.