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I have a damaged iphone 12 mini I’m trying to repair. It had been dropped and both front screen and rear glass were cracked. I have swapped the chassis and a fitted a new aftermarket screen. All seems to work except I get no cell service (no signal bars, no identification of msisdn in settings, and nothing helpful in field service mode). Wifi, gps and bluetooth are fine and the phone detects when the sim is present or not. The sim works fine in another iphone. Any suggestions on diagnosing if this is an antenna issue, a main board fault, or something else?
The easiest way to check if you have a parts problem or a board problem is to input *#06# into the phones keypad. If it displays the IMEI number it could be a parts problem but if it doesn’t display the IMEI number it will be a board issue most likely with the Baseband CPU.
Although this could be an antenna problem, based on your description my inkling is that this is a board problem. The thing with nearly all iPhones X and newer (aside from the XR) is they have a dual board layout. The logic board is actually made of two separate boards sandwiched together. The bottom board contains all the components related to cellphone service, and other wireless functions. The top and bottom boards communicate via an interposer board and a heavy enough drop can break certain lines of connection between the two boards, causing a bevy a cellular issues. Some additional info may help us narrow this down further. Where did the replacement housing come from? Did you transplant all the parts from the original housing? or were some already in the donor housing.
Hi there, it sounds like an Antenna fault so i suggest you try and replace the antenna and if that doesn’t work it will be a motherboard issue . Thanks
