Dropped MacBookPro 15” 2012 shows black screen

[David82827372]

MacBookPro 2012 15” A1398.
No visual damage was found.

Mac was inside of suitcase and it was inside of a bag.

Mac boots up,I can hear the chime,but the screen is totally black,not even “light” black. Caps lock light doesn't work.

I tried SMC,PRAM reset, didn't work.

Reconnecting screen display by unplugging those two things didn't work. I used this video







Reconnecting battery didn't work.

I also tried SMC,PRAM reset while the battery was disconnected and Mac was getting energy from the charger. Didn't work. I used that video.

What else can I do before changing the screen?I don't want to swap screen cause it's expensive.

[mon2]

The open lid sensor is in the trackpad. Fault may be there. Disconnect the keyboard and trackpad and test again. You can use tweezers to short the power button pcb pads to emulate the real power button. Search for smc on/off in the schematics. Do you have a high fan spin? Do measure the backlight voltage to ground. The lcd may be defective.

[David82827372]

The open lid sensor is in the trackpad. Fault may be there. Disconnect the keyboard and trackpad and test again. You can use tweezers to short the power button pcb pads to emulate the real power button. Search for smc on/off in the schematics. Do you have a high fan spin? Do measure the backlight voltage to ground. The lcd may be defective.

Hi. Thank you for response. I got 4 questions.
1. I tried looking how to disconnect keyboard and trackpad on YouTube on my model, but didn't find anything.
My model is MacBookPro A1398 15” 2012 mid and it looks like that one in the picture below. Don't mind the red circuses,I just pointed the spots I tried disconnecting earlier.
Can you please help me find a proper guide to do this? 2.Won't shorting the power button shock me? I better wearing rubber gloves,right?
3.Can you please explain or send a video guide from YouTube on how to measure the backlight voltage to ground?
4. I tried connecting Mac via hdmi to TV and TV says “HDMI no signal”. I thought,if the LCD is broken,maybe TV will replace it,but it doesn't even see my Mac. What does it mean?

[kevingill]

Try removing the display connector in the bottom left and then re-plug the Mac into the TV. It should force output to the TV. If a picture doesn't appear, then it's likely there's something wrong with the internals.

[mon2]

When you attempt the PRAM reset, does the unit perform the double chime routine? It should power up with a chime and then after a few seconds perform another chime if you keep the PRAM reset sequence of keys.

Wait a few minutes and apply a torch / flashlight onto the front side of your LCD display to check if you see a flashing folder graphic. If you do not have a valid operating system on the SSD stick, the caps key will not perform the LED toggle.

[David82827372]

Try removing the display connector in the bottom left and then re-plug the Mac into the TV. It should force output to the TV. If a picture doesn't appear, then it's likely there's something wrong with the internals.

Didn’t work. Weird how Mac does chime,but doesn’t work with tv via hdmi.

[David82827372]

When you attempt the PRAM reset, does the unit perform the double chime routine? It should power up with a chime and then after a few seconds perform another chime if you keep the PRAM reset sequence of keys.

Wait a few minutes and apply a torch / flashlight onto the front side of your LCD display to check if you see a flashing folder graphic. If you do not have a valid operating system on the SSD stick, the caps key will not perform the LED toggle.

Yes,it does double chime.
I don’t see a flashing folder graphic even if it is there somewhere because the lcd is probably broken.
By the way my keyboard don’t have led toggle,it’s an old model from 2012 mid. Screen brightness, F1-F12 are just buttons and they don’t light up just like the caps lock button.