As we all know, it is difficult to weld the copper connectors or other chips and elements on the tinned iPhone button pad. On the contrary, it is rather easy to weld the tinned connectors on it.
On that basis, we invented a tool which can add tin to the digitizer PCB connectors of iPhone and Android phones with parts from a broken iPad, and that has helped a lot in rising the efficiency of welding the connectors. You are recommended to follow the steps.
As usual, we connect the screen on this iPhone 11. Touch it, no response. Replace a well-reserved display which we have already testified its functions as a brand-new one, still, we found the touch screen failed to give any reaction.
We take down the display and unbolt the Phillips-headed screws before tearing down its logic board. We’ll inspect the digitizer PCB connectors on it and notice that there is a faculty. So the connectors must be replaced. Considering its double-laid structure, the lower layer might be pseudo-welded, and in that way we will be designed with more job.
Therefore we apply some aluminum foil around it then blow it under the hot air gun, 380℃, 40 wind. Disconnect the digitizer PCB connectors with a soldering iron under the temperature at 380℃. Disconnect the digitizer PCB connectors, apply some low-temperature tin on it and add some tin to the pins of the digitizer PCB connectors on the logic board with a soldering iron carefully.
First cover the tin on the whole area, add some tin to the pins that are not fully-attached. Then get off the excess tin with solder braid, apply the tin as little as we can to the two sides of the connectors or we add no tin. Because the extra tin on the two sides of the connectors might cause the pins between them pseudo-soldering. Take out some aluminum foil, apply it on the connectors of this new iPhone 11 to protect the area where shouldn’t be exposed to the tin.
Set the temperature to 320℃, 20 wind, apply the tin on the connectors of this new iPhone 11 to the iPad with a broken logic board. Meanwhile, add some tin on the pins on the other side, apply a little soldering paste, but not too much. The screen still gave no response when being touched
We measured the diode readings of after welding, again, add a little bit tin to where the readings are abnormal with a tweezer to make the tin on this pin fully attached.
We can see the diode readings now, the screen display normally, problem solved.
Here is some tips: we prefer replace the connectors on the broken logic board, because their pins are all tinned, but the new digitizer PCB connectors of the new iPhone are copper pins without being tinned. Once they are welded on the logic board, the pseudo-soldering might occur, followed by soldering faculty. So we tin the pins first to get higher efficiency and better results in soldering the connectors.
Please check out the video if you like to: