A1460 iPad 4 botched touch repair

[Nick]

Hi, I am fixing an iPad 4 with a botched repair on the lower touch flex connector. it came with some wires soldered up and then cut. removing the ruined connector showed the missing pads. I highlighted in red the ones completely ripped off on which I ran wires on the other side's test pads according to the board view.

the touch panel works fine but there is a small 5mm tall line in this position that is not responsive at all. I tried other glasses to be sure

how do i figure out what pin of the connector is the problem?

 

[dukefawks]

Diode mode the pins on compare to a donor board, one of them will have an issue.

 

[Nick]

Didn't think about using a donor board! Thanks, will try that out

 

[Nick]

i got around checking these, and every single pin is the same on a known working board. i even changed both connectors to brand new ones. could it be the touch IC?

 

[Electrontechnician]

Be careful with enameled wires, the insulation is rather easily nicked on sharp edge of the covers, I'd put some green mask around that for extra protection.

Green mask does not cure well if the circuit board is dirty with flux. After completing wire jumper repairs, give the circuit board a bath in alcohol in a smaller container placed in the ultrasonic machine without needing to empty the ultrasonic of it's different cleaning fluid. Then dry and apply mask, then will UV cure rock hard like what does should be.

I did same way to speed dry after washing out a logic board of it's mud out of the charging port using ultrasonic cleaning fluid (soapy like) then distilled water in a container in the ultrasonic machine then changed container for alcohol to dry the board faster. On this type, the mic is on the PCB with opening peeking through a drilled hole in the PCB meant I had to redo alcohol rinses using ultrasonic few times and drying again till mic worked properly. Mic is next to the charging connector so no choice here. Cellphone did a perfect dive spike into wet clay mud.

Cheers,