Chosen Solution
Hi guys, I have an iPhone 6 here. The phone has signal issue, keeps searching. In the settings the ICCID, IMEI and Baseband are all present. Upon testing, I found no voltage detected on VPA_APT line. I know VPA_APT line is powered by U_QPOET chip, so I replaced the U_QPOET chip, unfortunately it made no difference, still no voltage on VPA_APT, phone still has no signal. I also tested the coils L4001_RF and L4002_RF, they both have 3.9V, which I think is normal. I don’t know where to go next. Any help would be appreciated!
Interesting as I found a nearly identical question from last June on Jessa’s forum. The OP said that doing the U1/V1 jumpers solved the problem. For the original No Service error, I would focus on the ASM/WTR and WFR. In one case, I found that the top layer of the ASM had shifted and reflowing it solved the issue. You should also fully probe the BBPMU.
Without the background to the device im kinda thinking that it may be liquid damage? I would check that the line you mention against a known good board and make comparison. Then i would check PM8019
bro you only needed to replace C4005_RF that’s the main problem! I have fixed this lots of times already is due to low power on the Cap
