Iphone 6s back filter replacement..

[shani1122]

Hi, i got one iphone 6s . There was no backlight . I tested with multimeter there was short in anode line. I removed fl4012 n then checked short gone. Now problem is i cant solder the new filter as place is too small. I dont have hot tweezer . I m just trying to solder with hot air and soldering iron but no luck yet. Anyone knows any easy way to solder that filter with soldering iron or hot air? Or can i by pass filter with jumper wire?


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[vinse]

us an iron with small tip to tint your pads
and after that use hot air to solder your filter
this is for the soldering part

and please read again your filter name .the annode one on 6S is FL4211


but i think your wrong about this filter if you removed it and the short gone it's not the filter the issue !!! the filter can't be shorted
check bothe pads on eache side onnthe filter your short is still theire on one side

if it's on the left side that's meen C4211 is shorted (remove replace )
if its the right side that is more difficulte check C4022 C4023 yours diods (they are two) and the PP_VCC_MAIN caps
and check your backlight driver

at this end if by miracle they are not short still so you can jump your filter and solder it on TP22 for on side and the other side on C4023 (not the GND side ) thats will be ok

[shani1122]

Originally Posted by vinse

us an iron with small tip to tint your pads
and after that use hot air to solder your filter
this is for the soldering part

and please read again your filter name .the annode one on 6S is FL4211


but i think your wrong about this filter if you removed it and the short gone it's not the filter the issue !!! the filter can't be shorted
check bothe pads on eache side onnthe filter your short is still theire on one side

if it's on the left side that's meen C4211 is shorted (remove replace )
if its the right side that is more difficulte check C4022 C4023 yours diods (they are two) and the PP_VCC_MAIN caps
and check your backlight driver

at this end if by miracle they are not short still so you can jump your filter and solder it on TP22 for on side and the other side on C4023 (not the GND side ) thats will be ok

Thx for your reply. Sorry about wrong filter name. You are right its FL4211. I think i misunderstood about this short concept.if you can clear bit confusion for me it would be appreciated. When i test the pads of the filter with ground it beeps from one side but it doesn't beeps from other side of the pad. So thats mean there is shortage in the backlight circuit? I shouldn't get any beep from any side of the filter pad with the ground right? I didn't checked it with the line connector yet. In order check shortage do i need to test cap with connector line in continuity? For example if i connect one prob to lcd connector anode line n one to the filter n if i ill get beep the filter is short or not?


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[vinse]

hello if it's beep so the short still theire paye attention on wich side is it and follow my instructions
a filter never be shorted caus its not connected to the GND !!

[shani1122]

Originally Posted by vinse

hello if it's beep so the short still theire paye attention on wich side is it and follow my instruction

Will test it on monday n ill update.


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[vinse]

If it's beep in the number one side it shorted one the backlight circuit
if beep in the number two so it's the caps near the connector

[shani1122]

Originally Posted by vinse

If it's beep in the number one side it shorted one the backlight circuit
if beep in the number two so it's the caps near the connector

Thx for your explanation, will test on monday n ill post result..


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[vinse]

the C4022 and C4023 can be shorted also U4020

the pp_VCC_MAIN can be shorted too but you get no boot at all if the VCC_main shorted

[vinse]

you welcome have nice weekend

[shani1122]

Originally Posted by vinse

the C4022 and C4023 can be shorted also U4020

the pp_VCC_MAIN can be shorted too but you get no boot at all if the VCC_main shorted

Phone booting up but there is no backlight..


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[warboat]

clean the pads for FL4211 and jumper it

[vinse]

Originally Posted by warboat

clean the pads for FL4211 and jumper it

no don't his backlight is shorted fix that first

[vinse]

Originally Posted by shani1122

Phone booting up but there is no backlight..


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so check your backlight circuit

[warboat]

Originally Posted by vinse

no don't his backlight is shorted fix that first

he got it with no backlight probably because someone tried to replace screen and did not unplug battery and simply shorted the anode pin when plugging in the new LCD.
this is the majority of cases with FL4211 failure caused by techs. The backlight circuit is usually OK, just the filter did its job and died.
jump it and it should be fine

[vinse]

you right about usual issue on FL4211 but read the first post the FL4211 was shorted for him (beep on diod mode to GND )
so he remove the filter ( but a filter can not be shorted only ****ed )
so he tested each pads of this filter on side still short
it's he's backlight circuit wich is shorted he had to find he's short first fix this and finish by the FILTER

and the jumper is not a good solution cause filter act like fuse so it **** to protect the circuit so if you jump next issue the damages will be bigger