Malfunction Phenomenon
iPhone 7 Weak WIFI Signal Issue, this iPhone 7 just can receive several hotspots signal, less than the normal phone.
Trouble Shooting
In order to exclude possible failure of external accessories, we used a tweezers as an antenna to connect with WIFI antenna buckle (JUAT_RF), but the WIFI signal was still the same. Then we can conclude that the problem was from the motherboard, we checked the motherboard carefully, and we found the relevant area of WIFI circuit had been burned.
We move the “antenna” to resistor R7704_RF, here we can get many hotspots signal, it means that WIFI module was normal.
Then we moved the tweezer to the resistor R6711_RF, also normal. We continue to move the “antenna” to resistor R6705_RF, signal was abnormal, some hotspots disappeared, we can conclude that the main reason of the issue was PPLXR_RF.
For this issue, normally, we can jump a wire from from JUAT1_RF to R6711_RF.
We jumped a wire and test again, problem resolved.