Firstly, know that I have access to several iphones and sim cards. The issue is not the sim card; it works fine. I am also in a city where the signal is always at great. This particular phone was dropped hard. Inside the phone there was some ink of some sort that leaked out from under the lcd. Both before and after I opened the phone up I was getting service through T-Mobile. The signal was always very weak, meaning the signal status bars were ALL THE WAY DEPLETED but I was still able to make AND receive calls. Strangely, every call I made and received came in clearly even though the bars were down. Also, I NEVER LOST SERVICE DURING CONVERSATION. The problem though: just by leaving the sim card in the phone and letting it sit on a desk, the phone will eventually go into a NO SERVICE mode. All I have to do to get the phone working again is perform a soft reset and boom ba da bing, the T-Mobile logo with depleted bars returns, allowing me to make and receive calls. But of course it is only a matter of time (sometimes just minutes) before the No Service status returns. **its a 3g I've been reading and trying to trouble shoot. Someone said the pins in the sim card reader-- one might be loose? I looked and they all seem to give the same force. Also heard it could be the actual antenna. Finally heard that it was most probably the result of a tiny crack in the motherboard, and the only way to fix this issue completely was to replace the motherboard.... Anyone out there with knowledge about this issue would be greatly appreciated. I'm just hung up on this one. thx in adv.