The external image disappears too?
Test starting in safe mode.
Test starting in safe mode.
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Macbook A2141 820-01700 no image
- Thread starter ipetro
- Start date
You still have problems with GPU; or its VRAM.
In safe mode, dedicated driver isn't loaded; generic one is used instead.
In safe mode, dedicated driver isn't loaded; generic one is used instead.
ipetro
Member
when paired with an external display, it works not in safe mode but in normal mode! then the problem is somewhere with the definition of the built-in display! maybe the problem is in the u9850? what is responsible for starting the display line? a new graphic chip of the same model!
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When external monitor is connected, dedicated graphics (GPU) is forced on.
Maybe you have problems with iGPU instead.
Open an intense graphics app, like GPU stress; then disconnect external monitor.
GPU should stll be in use; check if you get image on internal monitor then.
Just in case, you can try changing U9850.
Maybe you have problems with iGPU instead.
Open an intense graphics app, like GPU stress; then disconnect external monitor.
GPU should stll be in use; check if you get image on internal monitor then.
Just in case, you can try changing U9850.
ipetro
Member
I replaced the U9850 but it didn't change the situation. I installed 4K video on two monitors and it works without problems. I waited for about 30 minutes and everything works stably! But as soon as I disconnect the external monitor, the built-in one works for about 30 seconds and the picture disappears.
Did you test this board with another LCD?
Not just testing momentarily the LCD into A1707 board.
Not just testing momentarily the LCD into A1707 board.
ipetro
Member
I checked in three different cases, the behavior is identical. As I understand it, the system determines the display as the system loads the Apple logo and the loading line, but before turning on the video, the entire display with the backlight turns off. And the system displays a display selection offer on the touchbar. Actually, the MacBook came to me with this problem initially, even before replacing the video chips. This means that another element is damaged somewhere. Which lines are responsible for the operation of the integrated graphics core in the CPU?
That is not so simple.
PCH, CPU, BIOS, graphics mux, are all involved.
So you've checked your MLB with 3 known good LCDs?
Then the problem is on the board for sure.
Compare voltage levels on J8500 with working board; find proper points for test.
I suppose, liquid spill affected another lines of the video connector.
Check if 3V3/5V_S0SW_LCD have correct levels.
When starting in safe mode, check in system properties, which graphics is in use.
PCH, CPU, BIOS, graphics mux, are all involved.
So you've checked your MLB with 3 known good LCDs?
Then the problem is on the board for sure.
Compare voltage levels on J8500 with working board; find proper points for test.
I suppose, liquid spill affected another lines of the video connector.
Check if 3V3/5V_S0SW_LCD have correct levels.
When starting in safe mode, check in system properties, which graphics is in use.