iPhone 5C no display

[Jenzo]

Hey everyone, I have an iPhone 5C here with no display (not a backlight problem). Boardnumber is 820-3928-A.

Now I have a complete lack of experience with iPhone 5C's so I'm in need of some advice. The phone has had previous repairjobs, shields are missing etc, but nothing really damaged as far as I can tell. No longscrew damage either.

Measuring everything in diode mode I saw that PP5V7_SAGE_AVDDH is 0.002 on C52/C156.

Should I assume U4 (chestnut) is to blame? It seems to have been removed or replaced before, can't really tell if well done.

Or is there anything else specifically I should check?

Thanx in advance!

[elecsoluces]

Re: iPhone 5C no display

Hello,

Can you post schematics for this board, I have only schematics for 820-3581-A
You have a short on 5V7_SAGE_AVDDH line.
Before removing chestnut check all caps on this line (only 5 caps).
On 820-3581 boards i had several times C69 shorted.

[Jenzo]

Re: iPhone 5C no display

Hi,

I'm working off the schematics for 820-3581-A as well since I can't find the ones for this board. But as far as I can tell everything is the same.

C69 (measures fine) is directly next to C52 (where I measure 0.002), so could be.

By checking these caps you mean removing them, and measuring them?

Small sidenote, I've put it under a thermal cam while waiting and chestnut is heating up. Altho this doesn't really mean anything.

Thanx for your time so far!

[elecsoluces]

Re: iPhone 5C no display

Your thermal camera says to remove chestnut and measure in diode mode PP5V7_SAGE_AVDDH. If short is gone you have to replace chestnut

[Jenzo]

Re: iPhone 5C no display

Will remove it tomorrow and check if the short is gone. Thanx for the advice.

[Jenzo]

Re: iPhone 5C no display

With a bit of delay, removed chestnut, short was still there, took a guess by removing C52 first since it was the easiest accessible and next to the cap you mentioned that always died. Short is gone, put chestnut back, booting phone with image. Thank you for your help!