iPhone 4S wifi gets hot
I have an iPhone 4S with wifi grayed out. I can’t turn on wifi.
I’v tried to replace the wifi IC using the one from donor board but when I turn on the phone wifi IC gets hot immediately. Donor board was tested and wifi was working.
The board doesn’t draw any amps when it’s not turned on, so there is no short to ground on the board.
I’v also tried to measure components in diode mode around the IC and everything looks ok (compared to measurements from donor board).
Since I had another donor board, 2nd one, I also tried with wifi IC from that board and same results - IC gets hot as soon as I turn on the phone.
When I put back original wifi IC the phone is working normaly, but wifi is grayed out, and bluetooth also doesn’t work.
The thing is that original wifi IC is USI 339S0154 and other two IC’s are different (see image). Could this be a issue why IC gets hot?