Super important announcement about FLCoS display!
Added 2023-11-02 12:39:48 +0000 UTCTurns out that when you buy the FLCoS display from AliExpress, there are actually two (or more) display driver boards that can be sent to you.
I have no idea what’s been changed between those two, as those seem to be exactly the same, but when you connect the 100mm ribbon cable, one of those boards will work fine but second one would only blink and turn off.
I’ve ran some tests, measured the voltages, tried different cables, different solder points etc. but the outcome was always the same.
I’ve managed to pinpoint the issue though. It turns out that when you solder additional ground wire from controller board and solder it to the display board, display will work normally on both Display Driver boards. I have no idea why it happens. My best guess is that some of the traces underneath the FFC connector on the driver board are actually shorted together.
Original ribbon cable (the short one) has some of it’s traces shorted together so it might mean that when you connect the longer ribbon cable, some of those traces won’t be connected to each other anymore because there are some PCB revisions that just don’t do that for you.
I don’t know why manufacturer made them that way. Maybe they don’t want you to use those boards with longer ribbon?
I’ve tried shorting the GND traces on the 100mm ribbon using my soldering iron but in the end I’ve just fried my display as GND traces are right next to the voltage ones.
TLDR: if your display blinks but won’t show the image - Solder the ground wire from driver board to the display board.
Comments
1. Check if you have the correct HDMI converter. It should be HDMI input and Composite output. There is also a one which has composite input and HDMI output. Both of them are almost identical. 2. If you have the correct board, it’s possible that the converter doesn’t get enough power. You could try soldering the USB cable to the converter board and connecting it to the power source.
Mañolo
2023-11-15 09:47:42 +0000 UTCNot strictly related, but do you have any idea why the display worked for me using the pi but not when plugged into my laptop? Additional info: 1. When plugged in, the screen lit up and was receiving power but did not display anything except flickering. 2. My laptop couldn't seem to decide if the secondary display existed or not, flickering between recognizing it and not. 3. It worked 100% correctly when connected to the pi. 4. This was using the hdmi converter wired directly to the display driver with no intermediary aux cable or adapter.
The Minecraft Destroyer
2023-11-15 08:57:50 +0000 UTC
