I’ve connected a Waveshare 2.8inch LCD to a Raspberry Pi 4 Model B, both new items received a few days ago. I’ve followed this WIKI to setup the display. No errors encountered during the setup but I am not getting anything on the LCD, in fact the display looks like it’s not being powered up, the screen brightness does not change when I start the Raspberry Pi. Can I get some assistance/tips in diagnosing the issue please.
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Assume this is the display you are using. Check the pin alignment to the Pi 4B, I had a similar one and had the pins misaligned. Not saying this is why yours is not working, but its a quick check and is something that has got me a few times when connecting things to the Pi.
Regards
Jim
Thanks Jim, I’ve double checked the pin alignment and it looks ok.
Attached are some pics, let me know if you notice anything abnormal.
Appreciate your assistance 
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Hi Eric.
Have not been following this thread but just looked at the pics.
Have the header pins been soldered into the display. It is a bit hard to tell for sure but it does not look like they are.
If not could be most of your problem.
Cheers Bob
Edit:
Just enlarged the 2nd pix from the top. The pins are not even all the way through the holes.
Thanks Bob, the header pins are soldered onto the boards. I did not solder them myself, they come soldered out of the box, I just align the male and female connectors together. I’ve also used a Multimeter to check continuity from the display header pins to the RPI pins and they are connected. The weird thing is, the display does not turn on, like as if no power is being applied but there is certainly a 3.3v being measured. I think the display unit maybe faulty, what do you think?
BTW, those expose pins are not used by the display unit.
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Hi Eric
Fair enough. They may be soldered on the other side out of sight.
You could be measuring 3.3V on the actual pins. If you can measure on the track or pad adjacent to the pin without touching the actual pin in case you have a faulty or damaged via or plated through hole
Does that display only need 3.3V or does it also need 5V?
I have no idea. Not big fan of RPi or Waveshare.
Cheers Bob
Alignment looks good to me.
Faulty display ?? could be, although all Waveshare and RPI stuff I have bought has worked ok. The display I was using had back light on all the time so easy to see when it had power. When it was misaligned the back light was off. I also put an insulating pad on the Ethernet port even though there was nothing on the display to contact it. Kept the display level better.
This one uses PWM for backlight brightness level according to the Wiki, a feature not available on the display I used. I seem to remember there was a problem with the HDMI and LCD connected at the same time and having to run a script to enable the LCD or to switch back to HDMI was a problem when you had no screen. The RPi also needs to have the HDMI connected before power on to load the drivers for it. I remember using SSH to configure the Pi before getting the LCD to work. I think it took me some time before I got it all to work properly. I also remember going through the github script extensively to understand it and try to figure why it was not working.
As this was some years ago I would have thought by now Waveshare would have fixed any problems. Just had another thought, the version of OS on the Pi might also be a reason why it is not working, suggest using the legacy as well as the current version.
All the best, hope you can get it working.
Jim
EDIT: Checked my notes from Jan 2023.
Tried for 2 days to use the Waveshare drivers. Ended up using this github link.
But it had its own issues. My notes say :-
ensure host name is raspberrypi and create the xorg.conf.d directory, if not already.
The display was a 3.5" with no backlight control. This was after looking into the configure script in detail.
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Hi Bob,
The type of connector used by Waveshare means the pins are just long enough to make it into the PCB holes not all the way through. On the LCD boards I had, I check with a wire wrap connector which has long pins. In my opinion this is not ideal as it could lead to the pins not being soldered correctly in the manufacturing process. I eventually got the boards to work but it was software not hardware at fault.
Cheers
Jim
I’ve finally managed to get this LCD operational. It took several reimages, but version 11.9 did the trick.
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Hi Eric.
It probably would be handy if the rest of the contributors knew what you actually did to get this operational.
Cheers Bob
Hi Bob,
As Eric said he reimaged Version 11.9 of the OS.
I assume he means Bullseye, the Legacy version of the Pi OS.
The latest version, Bookworm, incorporates Debian Linux developer changes in the way it handles applications and drivers not included in those that will run with Bookworm. For now it means; if something does not work with the latest Pi OS version, try the legacy version. It is not ideal but the onus is on the suppliers, in this case Waveshare to update their drivers and applications so they work with Bookworm.
This update can be costly and time consuming, so it won’t happen quickly, if at all.
It is a change by the Debian developers and not the Raspberry Pi Corporation.
Anyway that is my understanding.
I have managed to run some older stuff on a Bookworm Pi using the suggest method on how to do it. But I don’t think the LCD display would work this way because of how it changes the GUI interface at a system level. Also I think the GUI is radically changed in Bookworm, but I could be wrong.
Regards
Jim
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Hi James
As usual you have enlightened me somewhat. All a bit of a mish mash ain’t it.
That just about sums it up. They will wait until one of the more software savvy hobbyist types does it for them then go on raking in $$$$. Smart operators actually.
Cheers
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