Chosen Solution
So I just replaced the LCD panel on a broken Macbook pro and it seems to work, only problem is that now when turning the laptop on it chimes, and sits on a blank white screen. No apple logo or loading animation. What would have caused this and what can I do about it. The previous LCD panel had lines through it but apart from that it still worked so it wasnt an issue before. HELP! EDIT: I think I must elaborate on the issue, The LCD panel seems to work fine but when I turn on the machine, I hear a chime, the keyboard backlight turns on and I am able to change the screen brightness. But I see nothing on the screen itself. It is just a blank white screen without an apple logo, loading animation or anything of the like. I have attempted to see whether the LCD will work on another MacBook Pro, which was working perfectly before, but now the issue is happening on that machine also. Even when I put the original LCD in it. The SSD I had in the system did not move during the LCD swap so I don’t think the SATA cable has anything to do with it on the other machine, the one that I was fixing, maybe.
The issue is that component l9004 which is a 120ohm 1.5A transister in a 0402 size, blew up. Causing LVDS pins 2 and 3 to not recieve the 3.3V which it is supposed to recieve.
You’ll need an external adapter to a screen for further troubleshooting. If it works fine on an external monitor it’s more likely a Lvds cable or new screen issue. If you have no image even outside the Mac screen, trouble might be bigger.
White screen issues are primarily caused by the hard drive and/or the hard drive cable. On you particular model the hard drive cable is the main suspect. Apple had so many problems with this, they were replacing the cable of r free for several months. Where it gets damaged is at the point where it climbs the last step and goes over onto the optical drive. When replacing I put protection on either side of the cable to prevent the bottom case from contacting it. I use 3M extreme mounting tape to do it. https://express.google.com/product/97513… MacBook Pro 13" Unibody Mid 2012 Hard Drive Cable Replacement MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable To confirm this, remove the drive and boot from an external USB drive (preferably with El Capitan installed). If this condition has been going on for a while your data may be corrupted on your original drive.
