Hello, Did you replace the LCD panel, or the entire display assembly? You could have gotten a defective part, but it could just as easily be a problem with the backlight output on the board (you can blow the backlight fuse if the laptop is on when the connector is removed / inserted). I would disconnect the battery, remove the LCD cable, check the end for damage, and reinsert it if it looks OK. If you are comfortable with using a multimeter and probing small things you could check for backlight output voltage. I wouldn’t attempt this if you are not comfortable however, as it is relativity easy to slip and short something out with the probe tips.

Hello, It’s possible that it is a bad AMD graphics chip as well. If your iMac has the HD 6970 or HD 6950 this a really common failure, Unfortunately there were never updated cards for this machine to fix the GPU defect. If there is no image it’s likely the GPU. You should check if you have an image on the screen, by using bright light held against the LCD panel. You should be able to see something on the screen if the panel is getting an image I would definitely look at replacing either the backlight driver board.

Based on the information it does sound like a logic board / charge circuit problem. The flex cable in the pictures shown will be the trackpad cable I believe, and on this model is unlikely to cause that kind of issue. One troubleshooting step I will try is to power on the laptop without a keyboard, you should be able to do this with an 85 Watt Magsafe charger. I would recommend finding a shop that does logic board repairs to look at it - the 2012 15” is a laptop that I would still try to repair.

Your 2013 15” Macbook Pro is starting to show symptoms of a common failure mode - the power delivery IC for the graphics card has soldering that is faulty / cracks / wears out over time, causing intermittent graphics issues, until you lose display output entirely. The good news is it is a well known issue with a simple fix - if you take it to any competent repair shop they can resolve the issue permanently. Please check out the explanation of the issue here: https://www.macupgrades.co.uk/store/prod...

The keyboard flex only goes in the connector until it stops - that is a zero insertion force connector - so no pushing or forcing. If you managed to scratch the carbon traces on the plastic flex it may not work properly - plastic tweezers can be a good thing if you are worried about damaging it. If you remove the blue plastic from the tip of the flex cable it will not be rigid, or as thick, and will not get a good connection / or work at all. The plastic clip / clamp on the socket is mandatory - you will not get a good connection or at all without it. if it has slid off the back of the connector it is possible to put it back on with a magnifier and some tweezers - but be careful, it is easy to damage the connector. If you aren’t comfortable doing that I would take it to a local shop - once the connector is damaged it can be replaced, but you would be charged for logic board repair at a shop that knows what they are doing, and a less knowledgeable shop would want to replace the whole logic board.