Screen stays on after shutdown

[zentrum104]

Hi everybody,

right before christmas I thought I could finally finish my GBZ project, but as you can imagine I need a little help

Straight to the Problem:
After shutting down the Pi via the menu, the screen stays on and displays black and white flickering on AV1 input. The video signal from the Pi is displayed correctly on both inputs when the pi is running. If the video signal is connected to AV2, the LCD swiches to AV1 after shutdown and displays the flickering. I am pretty sure that the screen had turned completly black after shutdown during my tests. Even grounding AV1 completly does not make any diffrence.
I am using screen variant 12, bought from Amazon. I removed the 12V to 5V Buck-Converter as well as the big input L and C.

When did the problem appears?
I noticed a quite high current consumtion after shutdown, which was about 130 mA. To figure which of the components (uC, Audio-Amp, USB-Hub or LCD) is the reason for that, I disconnected the LCD power wire to measure the current directly with my multimeter. After my setup was complete I noticed that the screen do not turn of anymore. Because of the screen backlight, the current consumption after shutdown is now around 330 mA . Before my test I might changed some settings in the raspi-config menu, but I am pretty confident that that is not the problem, since I loaded a backup of my config.txt an the problem is still the same.

Has anyone suffered a similar problem before? What can I possibly do, to make the system behaves like before?

Thank you very much and merry christmas!

[Helder]

It would help to know what you are using to power your build and why is the Switch on your build not killing all power to the components like the LCD. Since we have no idea of your wiring or parts used or how you have your switch setup and therefore how power is routed no one can really give you a good answer.

[zentrum104]

Of course the build features a switch to disconnect the power completlly, including the screen.
Surely I can/will provide more detailed information about my power supply, when I am back from my christmas holidays. But I am not sure if that helps to solve the issue.

Let me describe the problem with different words:
During my build I did some tests with the screen. When the screen was powered and no input signal was applied, the screen was completlly black. Then I desoldered one power wire to meassure the current consumtion in this state. Suddendly the LCD behaves different, it stays on and shows the black and white flickering. I was not able to reproducs the "all black"-state, by resoldering the power wire. So what changed?

[zentrum104]

There is an update on the topic:
After ~10h normal gaming, last night suddenly the power supply of my built failed. It turned out, that the current consumption had increased to 1.5 A, which my power supply can not deliver and therefore shuts down. Reason for the high power demand is the display, which now uses 1.3 A .

In the picture below, I marked the components, which heats up fast (pink) and slowly(green):

IMG_20191227_130116.jpg (4.42 MiB) Viewed 2649 times

If no one have a better suggestion, i would assume that the LCD has finally died and the black and white flickering was a sign for the damage. Maybe it was damaged from an esd-stroke, while I desoldered the connection.

In case anyone is interested: I am using a Banggood power supply.