Hello and greetings from the Netherlands!
I am a microsoldering noob that just recently got into microsoldering and board repair, mainly as a hobby for now. I started hands-on practicing about a month ago by buying broken (mostly water damaged) iphone 6 phones. I've already managed to repair a few boards, which I think is pretty cool!
So now I'm working on this iphone 6 board which was severely water damaged. First thing I did was hook it up to bench power supply and immediately saw it was shorted as expected. I cleaned the board and verified short on main with my multi meter. I then knocked of the big ol' rusty cap next to wifi chip and that removed the short on vcc main. I replaced this cap with one from a donor board.
Next I proceeded randomly testing caps on the board and I found another short on PP5V7_SAGE_AVDDH. Since there are only three caps directly on this line I removed them one by one, checking for the short after each removal. With all caps removed from this line the short was still there. I proceeded by removing one of the ICs this line connects to (Meson). After removing this chip the short was gone. I reballed the chip and put it back. The short was back as well. I removed the chip again and replaced with a chip from a donor. Now the short was gone from this line! (I did put the caps back as well)
Going back to randomly checking caps on the board, I can't find any more shorts. I hook the power supply to battery connector, connect a screen and power it up. No smoke, good, aaand BAM backlight!.. image! But... All is not how it should be. I remember the boot screen to be white, and not pink! And the Apple logo has a shadow like band extending horizontally left and right to the edge of the screen. I tried another screen, same issue.
I turn the device back off. I take my multi meter and measure the voltage drop to ground on each pin of the display connector and compare them to a known good board from a previous repair. All pins check out. I do the same for the touch id connector and find an OL on pin 1 and 3. I guess this might be due to the filters on these lines, but I don't think this should give me a pink image and image artifacts.
What would be good way for me to continue troubleshooting the image problem?
I am a microsoldering noob that just recently got into microsoldering and board repair, mainly as a hobby for now. I started hands-on practicing about a month ago by buying broken (mostly water damaged) iphone 6 phones. I've already managed to repair a few boards, which I think is pretty cool!
So now I'm working on this iphone 6 board which was severely water damaged. First thing I did was hook it up to bench power supply and immediately saw it was shorted as expected. I cleaned the board and verified short on main with my multi meter. I then knocked of the big ol' rusty cap next to wifi chip and that removed the short on vcc main. I replaced this cap with one from a donor board.
Next I proceeded randomly testing caps on the board and I found another short on PP5V7_SAGE_AVDDH. Since there are only three caps directly on this line I removed them one by one, checking for the short after each removal. With all caps removed from this line the short was still there. I proceeded by removing one of the ICs this line connects to (Meson). After removing this chip the short was gone. I reballed the chip and put it back. The short was back as well. I removed the chip again and replaced with a chip from a donor. Now the short was gone from this line! (I did put the caps back as well)
Going back to randomly checking caps on the board, I can't find any more shorts. I hook the power supply to battery connector, connect a screen and power it up. No smoke, good, aaand BAM backlight!.. image! But... All is not how it should be. I remember the boot screen to be white, and not pink! And the Apple logo has a shadow like band extending horizontally left and right to the edge of the screen. I tried another screen, same issue.
I turn the device back off. I take my multi meter and measure the voltage drop to ground on each pin of the display connector and compare them to a known good board from a previous repair. All pins check out. I do the same for the touch id connector and find an OL on pin 1 and 3. I guess this might be due to the filters on these lines, but I don't think this should give me a pink image and image artifacts.
What would be good way for me to continue troubleshooting the image problem?
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