Very weird no service issue but works fine with Vodafone..
I thought I’d post this here to share an experience, and for anyone having a similar issue who may stumble across this thread - it may not provide a solution but it may save someone headache and effort trying to track this issue down. I’m not expecting an answer that will help with this, although I’d be seriously impressed if there is one!
I have an iphone 6 Plus, this phone was originally network locked to Vodafone. The phone works 100% fine with a Vodafone sim. This phone has now been unlocked by Vodafone around a month ago. Here’s the issue.. The phone will now accept sims from any network i.e it doesn’t show the sim locked screen, however I’ve tried several fully working sim cards from various networks with no luck! I have full reception in my area with Vodafone, O2, Three. When trying a Three sim card I get no service, Giff Gaff (operated by O2) I get no service. Strangely when I try an o2 sim, I get the o2 signal bars but they are all grey, so it shows o2 but with no signal and shows call failed whenever trying to make a call, however mobile data 3G and 4G works fine, with wifi switched off I can use 3G/4G with a reliable and fast connection. A Tesco sim (operated by o2) does the same. If I didn’t know better I’d have thought the phone may be blocked on these networks however o2 have confirmed it isn’t. To add to this I’ve managed to get the Three and Giff Gaff sim to work but only once after countless retries.
The IMEI is showing fine when dialling *#06#, the IMEI, modem firmware, ICID are showing in settings. The correct carrier also shows for all sims.
Inspecting the board there are no signs of water damage. It seems Tristar and Tigris have been replaced in the past. Struggling for ideas, and thinking it may be something baseband related I’ve reballed BaseBand and done the U1/V1 (long) jumpers. Needless to say this has made no difference. I’ve probed around in diode mode and found nothing that looks odd. Voltage wise I’ve found an issue with the output voltage from U_QPOET (VPA_APT), I’ve replaced U_QPOET and still have the same issue so I think this is more of a symptom than a cause. I’ve also replaced U_WTR_RF but to no avail.
I can only conclude there must be trace that has been damaged or possibly a cracked ball somewhere, but it seems whatever it is isn’t required by a Vodafone sim, which I find very interesting. I’m not sure if this is purely coincidence that the original provider was Vodafone, I think it must be. I’m not sure if there is some fundamental difference in how a Vodafone sim connects which allows the Vodafone sim to work or if it’s because Vodafone was the original provider, or is there a data line broken that tells the phone how to connect.. I suspect it’s more likely that Vodafone/the setup on the Vodafone sim cards allow the phone to connect differently than other sims, the reason I say this is I still don’t see the correct output voltage from U_QPOET even when testing with a Vodafone sim.
Very very odd, it’s a shame but I think this is another phone heading for the scrap heap :(
Ist dies eine gute Frage?