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any clue about display board change

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farfan14

Member
hello have 3 pcs display water damaged. 2 pcs A2337 display and 1 pcs A2338 all of them is good display just "display board" are damaged. i changed display board on all of them and all of them have same problem. soldering is 100% good. any experience ?

https://files.fm/u/pbf96hp844
 
2informaticos

2informaticos

Administrator
Staff member
You should reuse at least the EEPROM from original screen's board.
May need to change another BGA chip too.
 
F

farfan14

Member

here is youtube video where this man not changing any eeprom. so it is not bounded. seems there is io board revisions and need match it. so anyone know how to differ it's revisions? i tried several pcs non of them working. all of them is 820-02004
 
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farfan14

Member
now tried 2 more pcs and same result. when soldering io board back (from where i donored it) everything is working. so soldering excluded.. really strange problem:(
 
2informaticos

2informaticos

Administrator
Staff member
So you've located the backlight problem on the TCON board.
Maybe was better idea to inspect around LB8549 (49B1A07 in third picture); surrounding resistors and traces continuity to MLB connector.
Possibly corrosion underneath; can be fixed by reballing, or changing the chip.

DP855A is the Display Port controller and you can see on Aliexpress the sellers recommend to change it in case of screen replacement.
Keeping the original, as its EEPROM also.
The EEPROM should be the small 2AE chip, on the opposite side.

Aliexpress sellers post this advice for A2442 for example, but not for A2337/8.

LCD TCON.jpg

drive.google.com drive.google.com
But I suspect this apply on your case.
 
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farfan14

Member
on A2337/8 when changing whole display no need any ic transfer. so it is not bounded to the motherboard. so here doesn't have matching problem beetwen "main motherboard" and "display motherboard"! in this case we have matching problem between "display motherboard" and display metric.this board (in photos) now is not changed board. in this case I am trying to fix this board itself because of I could't solve change problem(matching). now on this board I already changed all ic except the bigger one. (mcu) I couldn't fix backlight problem yet.couldn't find any short and can't find any lost traces.i am checking now all resistors step by step and comparing other boards. I know if I change now whole board backlight will be solved but will be that weird old problem(lines). soon I will also change big ic and will check result

thanks
 
F

farfan14

Member
i coudn't fix it unfortunatelly.after mcu +eeprom transfer doesn't have image at all. so if anyone have any clue about this problem will be great. thanks
 
F

farfan14

Member
not possible. i have 10+ pcs ans also i have big experience into board level soldering. i am doing iphone cpu works. so it is not possible
 
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