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Old 07-16-2008, 15:58   #3 (permalink)
tkowsar
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Repair Display Problem Of China Phone-


China Mobile Display Type-
1. Flex system
2. Connector/socket system




Display Problem Come From-
1. Display Damage/Broken/ Broken Microchip area in display
2. Flex and parts damage
3. connector damage on both (pcb and display flex)
4. wrong software.
5. Display line broken from display connection to CPU.
6. CPU internal display section Damage.



1. Display Damage/Broken/Broken Microchip area in display
For this type of problem, have no way without display change (every one know it). so just
change display.
Display Microchip area on display panel-





2. Flex and parts damage
Sometimes we can see with our won eyes where is broken flex line or any parts.
but maximum time we can't see it normally. so we try to repair our display, when we confirm
phone show display problem only for display panel not for any type of pcb defect. can we
confirm it by replacing a good display on pcb. when we 100% confirm problem only on display
panale than we can try to repair it. otherwise first fix other problem.

For this type of problem can you repair flex cable with extra wire, but first need to
calculate flex cable all line with multimeter. some times line cross flex cable 1 side to
another side by in flex. so check them. and you try to change this type or parts, see picture-



here i mark some parts and only one type of display, other display parts find by your self.

though possible, change all parts from another display (which is broken but parts is ok)




3. connector damage on both (pcb and display flex)
Connector/socket system display create problem from there connector. so check simpaley there
all line with multimeter and fix them. though need join them with extra wire from direct pcb
to display. also you can change both socket.



4. wrong software

for wrong flash file or software problem we face white screen problem. so take any step before
do 100% Confirm its not for software problem.

we maximum time face this problem after flash or format. so after flash or format when a dead
phone is power on. we can 90% confirm its for wrong version flash file. so first see your
original flash file version than backup it and next flash phone with this same version
new/another ok file.



5. Display line broken from display connection to CPU.
98% china phone display line going direct cpu and other 2% have display ic. and sometimes
display line broken or break soldering from cpu to pcb middle point. just cpu bad soldering.
so can you try to re-hot cpu with your won risk.
also sometimes pcb internal line broken from cpu to display connection point. so check them
and fix them. (but do it after changing a good cpu though still display not ok)



6. CPU internal display section Damage-
Sometimes phone all section is working ok (without display) but have no display still after
change a good display (soft ok also) now you need to change must be cpu. because many time i see
phone all section work ok but have no display, after changing a good display phone is ok
100%. can anyone question, though its problem from cpu so how phone all section work ok. ans is
- phone all section work ok because only display area damage internally in cpu but all other
section have no problem
.


i explain it from my work and experiment. hope it help to you for repair a display of china phone.
now you can understood you start from where to repair a display. A wrong decision can't give you a success so read it carefully than do with your won risk.





wbr
tkowsar


Last edited by tkowsar; 11-06-2012 at 09:30.
 
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