iPhone 7 no signal repair

Machine model: iPhone 7

Fault phenomenon: repair one customermobile phone, no signal no serviecs, no card recognition, no charging.

Check that other functions are normal. Remove the two screws, remove the screen and take out the motherboard to check. It has been repaired. It is Previously repaired, which has been replaced. Moreover, it is a little crooked. Let’s do it first.

iPhone 7 no signal repair Figure 1.

Use pliers to cut the slot, cut it off, pull it apart, and slowly clean it. Drag it with normal temperature tin. Remember not to be too clean. Leave some tin.Find a Parts motherboard that has been removed from Nand. The SIM card holder should be removed upside down and the board should be placed upside down.SMD REWORK STATION 400 should blow the back of the card holder with wind speed of 50 and heat it evenly. About 10 seconds,or so can be removed gently with tweezers. The card holder is perfect.Put it directly on the board, add Flux, cyclone 320,After installation, insert the test card, put it into the back cover, and start up with 4G network. Dial 10086.
Now you can’t repair the charging, just look for the charging chip directly. USB VCC 5V standby VCC 1.8V, USB charging detection, main VCC,VCC starting, charging step-down output, battery VCC detection, charging drive signal, CPU power detection signal, all need to be tested one by one. Xu Weixu said, sometimes we need to talk about efficiency, first dismantle and then test, pick up SMD REWORK STATION to dismantle, Find Parts motherboard, remove one and install it, After testing or not charging, in order to save time, the USB management chip was also replaced.