Laptop Screen Flickering On Battery Power

I'm trying to fix a laptop where the screen flickers on battery power. It works fine but when you unplug the ac adapter the screen shows then goes black & flickers forever until you plug it in. I recently got my very first multi meter after I seen a fix for a different laptop with the same problem on Youtube. I have countless tools I just never bought one before, or really used one even though I'm far advanced in electronics & pc repair. I tried possible driver troubleshooting and Intel Power Settings changes. Yet nothing works but I'm sure this repair mans fix will do the trick. However I don't know how to find the same points, or even how to guess which points I should try before making the issue worse. Simply because this laptop is a different brand/model. I did disassemble the screen to the point where you can see all the screen boards solder points and pcb.

Here's the Youtube video repair for the same issue:


(Start at 10:10mins to avoid waiting)

How would I go about doing this? He basically stole extra power it seems from a dim button on the pcb points and jumpered a wire to the point where power was dipping on the laptop he's fixing. The repair man mentions that battery power isn't getting to the screen adequately & that's the only way to fix it. I actually grabbed a spare $60 battery on Amazon thinking it could be the battery first. & it wasn't... So however anyone can help me repair it would be super helpful as I've already invested time and money into fixing this myself. I just don't know what settings to use on the multimeter and which points to look for or steal power from. I can easily solder a wire quickly like him to do the repair, as I do have soldering skills. I just need to know where to do it.

Really want to use this Asus TP550LA without a cord.


Thank You