Chosen Solution
Hello guys. I work up today and the network keeps searching. I’ve narrowed down the problem to a baseband issue, since there is no modem or imei, so i would guess the baseband chip doesn’t receive any power. From what i’ve looked around it is a capacitor that fails, can someone who does this professionally let me know some schematics and what to replace to fix it? I’m pretty good with soldering, and watching Luis videos definitely helped me improve such micro work (only for hobby). Kind regards
You’ll need to search for and download the iPhone 5S schematic (hint: GSM Forums). Then you want to locate the page that contains the Baseband PMU (U2_RF). That will show you all of the power rails that are generated to support the Baseband CPU (U1_RF). Check each one of those to see if there is a short. Then you need to determine if the short is caused by a bad capacitor on that line, a defective BB PMU or an issue with the BB PCU itself.
