Macbook Pro medio 2012 A1278 - Battery died and now the LED screen is dim/dark

[JohannesBinder]

Hello dear Mac-geniuses,

I just bought a Macbook Pro medio 2012 A1278. The seller told me that the LED-screen was completely dim/dark. I thought that this would be easy to fix with SMC-reset and PRAM-reset. Unfortunately, this is not the solution.

The previous owner told me:
The battery of the Macbook ran completely dry and wasn't used (the Mac) for about 14 days. When the power cord was connected and the Mac turned on, the screen was suddenly dim/dark. With help from a flashlight it is possible to see what is going on.

When i connect the Mac to a TV through the Thunderbolt it is perfect. But when there is no external monitor connected, the screen is dark and a flashlight is required. I have read a ton of threads etc. throughout the internet the last couple of days, but can't seem to find a specific answer. For example a guide to change the LED-inverter or so? Any suggestions?

Ran a hardware test and got 1 failure:
4BAT/6/40000005 : 0x8984eb90

//Johannes Binder //Denmark

 

[TheIguana]

The easiest solution would be to buy a new display assembly (https://www.ifixit.com/MacBook-Part...Unibody-Mid-2012-Display-Assembly/IF163-042-1). If it is the display inverter board is indeed dead then that is typically held under the black plastic clutch at the bottom of the display. There isn't a lot of documentation on removing it but I don't believe you will need to remove the glass cover of the display.

The hardware test error you got is just telling you your battery is dead. All modern Apple laptops throttle extensively (~50%) when the battery is dead or has been removed. So once you get the display working you are going to want to replace that.

 

[JohannesBinder]

The easiest solution would be to buy a new display assembly (https://www.ifixit.com/MacBook-Part...Unibody-Mid-2012-Display-Assembly/IF163-042-1). If it is the display inverter board is indeed dead then that is typically held under the black plastic clutch at the bottom of the display. There isn't a lot of documentation on removing it but I don't believe you will need to remove the glass cover of the display.

The hardware test error you got is just telling you your battery is dead. All modern Apple laptops throttle extensively (~50%) when the battery is dead or has been removed. So once you get the display working you are going to want to replace that.

Thank you very much for your quick response. I will move on with your advice!