How to fix iPhone 7 Plus Half Dim Screen? - GSM-Forum

Amanda0820 · 11-26-2018, 09:28

The situation:

IPhone 7 plus half back-light as show as following, after check the logic board carefully, there is no deformation nor signs of water damage.

What's wrong with IPhone 7 plus screen?

1. Take apart the phone and remove the display assembly. Take out the logic board. Run diode mode measurement of backlight relevant pins on the display connector J4502. The measured value of Pin 45 is OL, which is abnormal. A normal value should be around 450.

2. Check with schematics, you will see the voltage outputted from the backlight IC U4601 reaches Pin 45 of J4502 by way of C4602, FL4601 and C4605. So continue to run diode mode measurement of C4602. The measured value is normal. Judging by this, the abnormal value of Pin 45 is probably caused by open-circuited condition of its relevant circuit or malfunction of the display connector J4502. Check J4502 carefully and we find that Pin 45 has been pseudo soldered.

3. To further confirm the faulty position, desolder the J4502 from the logic board. To desolder the connector, first stick High-Temperature Tape on components around for protection. Then apply some Paste Flux to J4502 and remove J4502 with 858D Hot Air Gun afterward.

4. After the removing of connector, we get access to measure the diode value of Pin 45 on the bonding pad. The measured value is normal.

5. As of now, we can confirm that the fault is related to J4502. We can fix the problem by replacing with a new display connector. Next, heat with 858D Hot Air Gun. Clean the bonding pad with rosin soaked Solder Wick. And clean with PCB Cleaner afterwards. Apply some Paste Flux to the bonding pad. Get a new display connector in position and solder with 858D Hot Air Gun. Next, secure the four sides with Solder Paste for successful soldering. Once done, clean with PCB Cleaner.

There also have video about iPhone 7 backligh/dim screen repair for your better understanding.

simeon_tsvetkov · 12-11-2018, 16:43

Huh ?!
Pardon my French, but I think that all this is bollock.
Why remove the fpc connector ? Why not measure the backlight fuses instead ?? I'm confused ...

kgnaccessories · 12-28-2018, 20:33

this is helpful advice

Tareqd60 · 01-09-2019, 10:07

I had one nightmare reparation done for iphone 7p half backlight

plesae have alook

https://www.youtube.com/watch?v=8ysLDWPe4JI&t=10s

11-26-2018, 09:28	#1 (permalink)
Amanda0820 Freak Poster Join Date: Aug 2018 Location: China Posts: 158 Member: 2861866 Status: Offline Thanks Meter: 71	How to fix iPhone 7 Plus Half Dim Screen? The situation: IPhone 7 plus half back-light as show as following, after check the logic board carefully, there is no deformation nor signs of water damage. What's wrong with IPhone 7 plus screen? 1. Take apart the phone and remove the display assembly. Take out the logic board. Run diode mode measurement of backlight relevant pins on the display connector J4502. The measured value of Pin 45 is OL, which is abnormal. A normal value should be around 450. 2. Check with schematics, you will see the voltage outputted from the backlight IC U4601 reaches Pin 45 of J4502 by way of C4602, FL4601 and C4605. So continue to run diode mode measurement of C4602. The measured value is normal. Judging by this, the abnormal value of Pin 45 is probably caused by open-circuited condition of its relevant circuit or malfunction of the display connector J4502. Check J4502 carefully and we find that Pin 45 has been pseudo soldered. 3. To further confirm the faulty position, desolder the J4502 from the logic board. To desolder the connector, first stick High-Temperature Tape on components around for protection. Then apply some Paste Flux to J4502 and remove J4502 with 858D Hot Air Gun afterward. 4. After the removing of connector, we get access to measure the diode value of Pin 45 on the bonding pad. The measured value is normal. 5. As of now, we can confirm that the fault is related to J4502. We can fix the problem by replacing with a new display connector. Next, heat with 858D Hot Air Gun. Clean the bonding pad with rosin soaked Solder Wick. And clean with PCB Cleaner afterwards. Apply some Paste Flux to the bonding pad. Get a new display connector in position and solder with 858D Hot Air Gun. Next, secure the four sides with Solder Paste for successful soldering. Once done, clean with PCB Cleaner. There also have video about iPhone 7 backligh/dim screen repair for your better understanding.

12-11-2018, 16:43	#2 (permalink)
simeon_tsvetkov Insane Poster Join Date: Apr 2013 Location: London Posts: 61 Member: 1911098 Status: Offline Thanks Meter: 16	Huh ?! Pardon my French, but I think that all this is bollock. Why remove the fpc connector ? Why not measure the backlight fuses instead ?? I'm confused ...

12-28-2018, 20:33	#3 (permalink)
kgnaccessories Junior Member Join Date: Dec 2018 Posts: 9 Member: 2885508 Status: Offline Thanks Meter: 1	this is helpful advice

01-09-2019, 10:07	#4 (permalink)
Tareqd60 Junior Member Join Date: Jan 2019 Location: Denmark Posts: 20 Member: 2886931 Status: Offline Thanks Meter: 8	I had one nightmare reparation done for iphone 7p half backlight plesae have alook https://www.youtube.com/watch?v=8ysLDWPe4JI&t=10s