iphone 6+ dead, suspect on vdd_cpu

[disorder4]

hello,
i need some help i have to repair a i6+.
first it have water damaged. the phone worked ok after drying
some month later it showed display driver failure


so a first repair atempt was done by a technician (i don't know him):
replace driver : the same
and he said the owners "your iphone is unrepaparable"



then the owners sell me the phone to try


first i noticed some weird things :
-cumulus removed
-one filter on mesa line removed
-many many dry flux (like rosin) under cpu shield and around touch ics


first i resolve the problem with display, it was a cap short to ground near screen connectors on PP5V7_LCM_AVDDH_CONN (c2094)


the phone start , and show home screen. but home button don't work caused the filter; and touchscreen not work caused by absence of cumulus


the day after : phone dead again :


show 0.50amp on power supply after start button pushed
reflow display driver


now the launch sequence seems ok at the beginning : 0.14-0.30-0.90 but after this it dropped to 0.15 and do cycles between 0.15 and 0.65


the cpu is really hot when it is 0.90 and when the power supply rise to 0.65


no short find anywhere


but i found that the coil L1209 on vdd_cpu is colored black on the half near cpu
in diode mode i have 184



when i put my power supply on vdd_cpu , anywhere on the line, the power line drain 2Amps



can it be a short to ground by a faulty caps but without 0 on diode meter ?


or can it be a short caused by the coil ? but the coil is not connecter to ground.


if someone can help, thank you.

[DeeCoy]

It could as well be to much resistance on some line and thats why it's drawing so much. Well, if you see 100% broken cap, remove it.. You know what Jessa says right? Remove the ugliest guy 1st.

[ninos22]

Originally Posted by disorder4

when i put my power supply on vdd_cpu , anywhere on the line, the power line drain 2Amps



can it be a short to ground by a faulty caps but without 0 on diode meter ?


or can it be a short caused by the coil ? but the coil is not connecter to ground.


if someone can help, thank you.

VDD_CPU on iPhone 6 Plus? hmm

[7Axis]

Do you mean PP_CPU?

Be concerned about the flux around the CPU, if I remember correctly PP_CPU traces under the CPU are very close to the top edge(near LCD display power IC&display controller IC)

If you meant to say PP_CPU, it's likely the previous technician, or yourself, applied too much heat around CPU working on these display ICs and shorted PP_CPU..

Also never try and inject current inside a short, unless it's VCC_MAIN... CPU rails are extremely sensitive, I'd never try to inject 2Amps even if it's rated for more, You could have easily fried the CPU beyond repairable right there..

Anyhow you can still check resistance to ground, see if PP_CPU still provides a steady voltage.

[ninos22]

Wow I didn’t notice, you drop 2A in PP_CPU? bb cpu xD