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820-4924 no LCD/ KBD backlight 2015 LCD Screen Compatibilty

Bouba148

Bouba148

New member
Hi team,

I have a 820-4924 that was supposed to have a liquid damage, but when i opened it this one was very clean, no liquid traces, all water pads are white.
here are the 2 symptoms:
It always turns ON ( chime, display ) but sometimes the fan doesn't spin, i did a SMC reset but no changes.
I have no lcd and kbd backlight but i have PPVOUT_S0_LCDBKLT at 50V and PPVOUT_S0_KBDBKLT at 5V which means that there is no load ( screen backlight not detected ) as Louis explained it here https://www.rossmanngroup.com/board...acbook-air-no-backlight-troubleshooting-guide.

I wanted to know which macbook screens are compatible, because I've tried good screen coming from a 2012 retina but I have no display/backlight at all.
Should I only respect the manufactured year whatever it's an Air or Pro or should it be the exact same model?

Thanks
 
Last edited:
J

JohnB8812

New member
1. The fan only spins on this model when the CPU gets warm. Not an issue just a stupid feature.
2. The ONLY LCD that will work with the 4924 is a 2015 13" display. 2013/14 will have picture with no backlight. Must be the 2015 screen.
3. Keyboard backlight I have no idea. Tried another keyboard backlight?
 
D

dukefawks

Administrator
If you have 50V then you have the correct LCD. Pin 1 on the connector or cable is probably damaged. Could also be inside the LCD but that is more rare. Inspect connector and cable first.
 
Bouba148

Bouba148

New member
Hi Dukefawks,
Once again you got it: it was the cable, pins 1 & 2 disconnected, also visually pin 1 didn't look good at all but on the connector at the LCD side, I mean in the LCD assembly.
Now backlight ok, I'm posting with it now.
But regarding the fan, I've installed Macs Fan Control and forced it to a constant speed but the fan doesn't spin, and the app reports speed at 0 as feedback.
Fan is controlled by the smc through the U5870, Q5871, Q5872 and Q5873, right?
Could you please quickly explain me how is it working, just wanna make sure I don't miss something.
Thanks in advance.
 
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