"WIFI signal is weak, which part should I replace" için yanıtI corrected this problem recently. The first repair shop replaced the customers damaged chassis with a used one. This is when the 2.4GHz signal evaporated just as described. After I got the device history, I replaced the chassis with a nice straight one and that corrected the 2.4GHz signal problem. If you're 5GHz signal is strong, it's not likely to be the F-cable. You can further narrow it down by testing GPS and BT which use the same antenna. If they both work well, it's probably a bent chassis.