The iPhone 6 Plus LCD screen has replaced the new, however, when we press the iPhone power button, the iPhone screen has no display for a long time. It can receive the calls, just no display. Let's get help here!
Check the iPhone appearance, there is no damaege. Replace the new LCD screen, the problem is the same: no diaplsy and no backlight.
The
measured value is completely normal, there is no current burnt traces on the
iPhone backlight chip and display power supply
IC, so we can start to work on its display part. Taking off the display IC under good
protection, and work on solder pad with low temperature solder, do not rush to
replace the new IC, the bottom resistance should be measured before that. As
shown in picture 1.
The
result shows that the D3 pin I2C bus CPU has no resistance to the clock signal
of the display power, and the C3 display has no resistance to the power IC
signal. According to these two results, we can make sure that the lock screw is
wrongly installed to cause the motherboard layer being broken. Open the 6P
bottom screws column diagram,we find that C3 go through left and right sides of
the screw column, D3 only go through the left, After removing the 2 screw
columns, we find both of them get traces of damage (you can remove the screw
columns with solder paste, hot air gun with 300 degrees and gently push then
down by QUICK 861DW Hot Air Rework Station), we find there is
serious disconnection on the left. As shown in picture 2.
First,
scraping a waste main board without broken wire and observe the wire construction.
Select a smaller phone fix scraper tool,
gentlely scrape and try not to damage the bottom wire since there are several
layers in the iPhone 6 plus motherboard.
you need to pay attention if there is black layer shown up for sraping the
first layer, then you can add a bit of soldering paste on it, it will be clear
to see the specific location of the wire under a microscope.
We choose a similar sharp
knife to throw off the location of the broken wire and find the thread. The
left screw can find a resistance thread. We choose a sharp iron with
professional jumpers to solder every wire carefully and try not to repair it
next time.
We
can solder the jumper under the microscope,
as shown in picture 3, the screw column on both
sides of the line have in common, the left one can not find the thread so we
can use the right column to make jumpers, then we measure IC bottom pin
resistance again. The resistance is normal, now solidifying with green UV oil and install
display power supply to test.
Now the iPhone 6 Plus LCD screen can be lit, you can use the iPhone normally!
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