Things happen in runs. I had two clients with the same model Macbook, and each computer had the same problem. The two clients came to me within two days. It seems to be an unlikely coincidence, but maybe it's not.
One computer's display didn't light up at all, though the client said he could get it to light up if the lid lifted just a crack, insufficiently to read it. I couldn't even get it to do that. The other computer did display, but you had to move the lid back and forth several times. I was sure it was on its way out.
I knew it was either the inverter or the cable in each case. It might have been both. But since the repair takes so long, I ordered an inverter and a cable for each. I didn't want to do the repair twice for either computer.
The procedure took a long time, even after practice. It took at least three hours for each computer. The hardest part was putting the plastic tabs back into the screen to make the bezel snap in. That took an hour!
The plastic Macbook is not really well made. The plastic case tends to fall apart, and so do some internal plastic pieces. It's a good thing Apple stopped making them. I find it odd that Dell and other companies know how to make a plastic laptop both durable and serviceable. The Apple is neither. Apple computers are normally very durable, but they also tend to be the hardest to service. I don't know why this is. Thank goodness for ifixit, which guides us through it all.
Use plenty of light. Use small containers for all the little parts. I also use a digital vernier caliper to measure the lengths of the screws. The measurements I got are different from those on ifixit, so I learned to compensate by a little.