The wifi on one of the older laptops in my collection failed quite a while ago. At the time, I figured the wifi card in the laptop had died, and got a USB wifi dongle to get it back online. Didn’t think much else about the problem after that.
This morning while I was looking inside to see what could be upgraded, I decided to pop the wifi card out to have a look. The top didn’t look too unusual, but when I flipped it over, there was a big toasted area on the label. Looks like the wifi chip got a bit hot and burned itself out.
The wifi card bay also showed some evidence of the heat. The area was a bit tacky, so I think it might be adhesive residue from the sticker on the back of the wifi card.
I popped the RF shield off the card and saw a bit of browning on the board from the overheating chip.