iphone 6s backlight problem - GSM-Forum

orx · 10-28-2018, 22:19

hi guys

i need a advice.

iphone 6s no backlight :
history
lost backlight after that customer has replace screen without remove the battery..
my steps :

replace all the backlight lines so , fl4211 (was burn) , d4020, d4021 , l4020, l4021 and U4020 .
but the problem persists because i have a short on C4020 , C4021 , C3387 PP_VCC_MAIN.
I lost a few hours but I can not find this damn short ..

any advice ?
thanks

disorder4 · 10-29-2018, 02:01

hello,

have you try freeze spray or rosin smoke method (see rewa on youtube) ?

orx · 10-29-2018, 11:22

yes bro i checked with freeze but i don't see overheating..

ninos22 · 10-29-2018, 12:54

Quote:

Originally Posted by orx

hi guys

i need a advice.

iphone 6s no backlight :
history
lost backlight after that customer has replace screen without remove the battery..
my steps :

replace all the backlight lines so , fl4211 (was burn) , d4020, d4021 , l4020, l4021 and U4020 .
but the problem persists because i have a short on C4020 , C4021 , C3387 PP_VCC_MAIN.
I lost a few hours but I can not find this damn short ..

any advice ?
thanks

To see the warm up point with freezer you need to put out Q2300 and drop 5v (0.5-1,0A) on VCC_MAIN.

Probably the short is from U4020, try to put out if you think is easier for you instead drop 5v to the line.

orx · 10-29-2018, 14:14

removing U4020 short is still present so i 'll try put out q2300and drop 5v. thanks i will let you know.

7Axis · 10-29-2018, 14:34

ninos22 is correct, you won't find the real short until you remove Q2300...

How much amps/mAmps is your phone drawing to power supply when not powered?

It'll tell you VCC_MAIN short size, the lower the amp the harder it is to find.

10-28-2018, 22:19	#1 (permalink)
orx No Life Poster Join Date: Oct 2012 Location: Republic of Serenissima Posts: 1,516 Member: 1825965 Status: Offline Thanks Meter: 874	iphone 6s backlight problem hi guys i need a advice. iphone 6s no backlight : history lost backlight after that customer has replace screen without remove the battery.. my steps : replace all the backlight lines so , fl4211 (was burn) , d4020, d4021 , l4020, l4021 and U4020 . but the problem persists because i have a short on C4020 , C4021 , C3387 PP_VCC_MAIN. I lost a few hours but I can not find this damn short .. any advice ? thanks

10-29-2018, 02:01	#2 (permalink)
disorder4 Insane Poster Join Date: Oct 2013 Posts: 72 Member: 2038120 Status: Offline Thanks Meter: 11	hello, have you try freeze spray or rosin smoke method (see rewa on youtube) ?

10-29-2018, 11:22	#3 (permalink)
orx No Life Poster Join Date: Oct 2012 Location: Republic of Serenissima Posts: 1,516 Member: 1825965 Status: Offline Thanks Meter: 874	yes bro i checked with freeze but i don't see overheating..

10-29-2018, 14:14	#5 (permalink)
orx No Life Poster Join Date: Oct 2012 Location: Republic of Serenissima Posts: 1,516 Member: 1825965 Status: Offline Thanks Meter: 874	removing U4020 short is still present so i 'll try put out q2300and drop 5v. thanks i will let you know.

10-29-2018, 14:34	#6 (permalink)
7Axis Freak Poster Join Date: Nov 2017 Location: Canada Posts: 131 Member: 2777379 Status: Offline Thanks Meter: 34	ninos22 is correct, you won't find the real short until you remove Q2300... How much amps/mAmps is your phone drawing to power supply when not powered? It'll tell you VCC_MAIN short size, the lower the amp the harder it is to find.