Chosen Solution
Laptop would not boot up (stall at the Apple load screen then turn off, was overheating before total fail) looked up the issue on the net. Indicated the issue maybe the logic board, had issues getting the old one out (not the most technical) installed the new board with no major issues. Now the screen won’t come on, and so I can’t tell if the fix took, checked the cable connections they look good but no expert. Would like to get another 2 years out of this, any pointers?
Step one would be to disconnect the battery, then try to re-seat the display cable after checking that the connecter on the board and the tip of the display cable are not damaged in any way (step 8 of this guide); then re-connect the battery and restart. A- If the laptop is not restarting (fan not running), you have a dead logic board (assuming you have a known good and charged battery and/or you are connected to the wall charger, and everything else in your laptop is properly assembled, all the cables properly re-seated). B- If the laptop restarts but you cannot see an image, try flashing a light on the Apple logo on the back of the screen. A spot of light will appear in the middle of the screen. -B1- If you see something written, the LCD is turned on but there is no backlight (could be an LCD issue or a logic board issue). Best would be to try a known good display to be able to tell where the issue lies. -B2- If you see nothing written, connect the laptop to an external display such as your TV via HDMI. -B2-a- If you see an image there, it is likely you have a faulty display or a faulty display cable. Of course, you can try to change the display cable using this guide, but it is a bit of a pain. Then you will be able to tell if it is the LCD itself or the cable. Instead, same as in -B1-, I suggest trying on a known good display assembly if possible. -B2-b- If you do not see an image on the external display, then your laptop is not “producing” any image, and you have a faulty board. Hope I did not forget any steps..
Is your problem no BACKLIGHT or no IMAGE? Also, can you see the screen “activate” when it comes on? Meaning, when the laptop comes on, you can see the little ting that looks like ink moving around inside the screen? You should have 3.3v on pins 2, 3, and 4 of the LVDS connector, and 27-40 on pins 21 ad 22. If you have 0 volts on pins 38/39/40 you blew a backlight fuse. if you have 0v on pins 2, 3, or 4 you either got an F’d logic board or messed something else up that will be a PITA to solve. Get measuring and let’s get started. EDIT: Nevermind, I see you see an Apple on the screen. Just no light. So we have two possibilities here. a) You blew the backlight fuse, 0v on pins 21/22 of LVDS. If you have 0v here, 99% chance you F’d it up. b) The board you got is a POS and not boosting. If this is the case, you’ll see 12.6v on pins 21/22 of the LVDS connector. This means the fuse is intact since it is sending the main power rail through to the screen, but U9701 Is not using the inductor to boost it to the level required to power the screen. In this case. If this is the case, they sold you a faulty board, file chargeback and send it back. Or fix it if you want to, I’ll help walk you through it, but this won’t be easy or fun if you are new to this and you really should be reimbursed for the wasted time. From what you posted this is an 820-2530 board, LP8543 Based, so there is a fighting chance of making this work. No proprietary APP001 BS!
