Thanks in advance for all your help. I have check forums and also search online but no luck. Anyhow, I do have two(2) Galaxy S3 SGH-I747M. I factory reset them already and works fine except I'm having problem making phone calls or receiving phone calls. When I insert the SIM card, it recognizes the carrier and getting signal. As soon as I make a phone call, the signal level drops to lowest 1 bar and it's not dialing or I'm not hearing the ring sound on the other line.
I'm asking if there is a way to reset the Samsung Service Menu Settings i.e. *#197328640#. I have a feeling the previous owner messed up the two phones. It was rooted but failed root since services stop running and SU app not working. So I un-rooted both phones and they are now running stock firmware. I factory reset via recovery menu and wipe cache as well. But still no luck. Everything else works but it seems I'm not getting signal. I tried my sim cards with another phone and it works fine. I played around with network settings but no luck still. Any of you guys experienced this?
I have already check the antenna and it's securely connected. I'm just stomped right now. I have a feeling the service menu was fiddled around with before so I just want to know if I can reset it to default settings.