PicorePlayer RPI4 - Touchscreen went Black !

[sdiesel77]

Hi All,
Something weird happened with my setup few days ago.
I m using a RPI4 with Picoreplayer and a 7" Touchscreen for years without issue.
The RPI4 and the screen have separate PSU.

The screen went completely black! The RPI is still working well.
I checked the screen PSU (small USB charger) and confirmed it was still working fine.
I then decided to order a new screen, received it today, replaced it and Still the same issue!

I really don't get it!!! Anybody to help Pleassssssssssssse !

[sdiesel77]

[Paul Webster]

Do you see anything at all on the screen during the boot phase?
Do you have a spare SD card? If yes you could try making a new pCP on it or Raspberry Pi OS and see if that works.

[sdiesel77]

Do you see anything at all on the screen during the boot phase?

No nothing at all, not even a color flickering

Do you have a spare SD card? If yes you could try making a new pCP on it or Raspberry Pi OS and see if that works.

I could try indeed, nothing to lose here.... thx

[sdiesel77]

Tested today with a new SD card and exactly the same issue unfortunately
I remember that in the past even with Rpi4 off the screen was flickering, here there is nothing it stays black...
I tried a different charger for the screen, same issue.
How can I confirm it's not an issue with the screen?

[sdiesel77]

It seems I fixed the issue but in a weird way...
I had to add jumpers to take the power from the RPI4 to screen as when using a different adapter via the USB of the screen board, the screens stayed black.
Any idea why?
I never had to use these connections in the past.

[sdiesel77]

[sdiesel77]

And now, I have a power logo ⚡ appearing which means I presume the power isn't strong enough...
I could potentially increase the voltage but I still don't understand why suddenly it stopped working with external charger...

[paul-]

Powering the screen from gpio has always been the standard way of powering. https://www.raspberrypi.com/products...touch-display/

The 800 x 480 display connects to Raspberry Pi via an adapter board that handles power and signal conversion. Only two connections to your Raspberry Pi are required: power from the GPIO port, and a ribbon cable that connects to the DSI port on all Raspberry Pi computers except for the Raspberry Pi Zero line.

but regardless, your connections and the lightning bolt shows you don’t have sufficient power. Be careful that you don’t increase the voltage higher than spec. There are many things that can cause power to be low. Besided just a power supply that is starting to fail, it can be problems with the usb connector too.

[sdiesel77]

Thanks Paul for the response.
I tried 2 different usb chargers and none worked for the screens... it's like the USB power input of the screen stopped working....

[sdiesel77]

Anybody has an idea on What happened here please

[Grumpy Bob]

Can't offer anything on the black screen, but I found that the USB power supply was critical with the screen installed - an old iPad charger seemed powerful enough to me. Also worth investigating is the USB cable, thinner, longer cables don't seem as good as shorter better built ones.

Robert

[sdiesel77]

Thanks Robert, I decided to order a new powerful regulated PSU of 5v -10A. A bit overkill but at least I won't have power issue anymore.

[Greg Erskine]

NOTE: The official RPi4B power supply is 5.1V. The extra 0.1V is to compensate for voltage drop across the USB cable.

The only problem I ever have with the Official 7" screen is with the ribbon cables. The ribbon cable sometimes isn't seated properly or the ribbon cable will actually break after years of flexing.

[sdiesel77]

I am using a 5v (set at 5.3v) 2A regulated PSU but it seems that it's still not enough one the screen is connected...
The new 10A will not have this issue 😃