iPhone 7 searching for network after audio ic replacement, need advice - GSM-Forum

sn4k3PT · 07-10-2018, 21:17

Hello,

iPhone 7 had the problem with audio ic which i fix with the jumper, phone worked before it just don't get any audio. I replace chip and now audio works again.
Problem is it keep searching for the network. Before people say, i know i may have reflowed the BB CPU, i didn't use a preheater, and i read all that info just now.
The thing is i have IMEI, then i tried to restore to check the error, it stops at 80% when sending the BB at 3utools, error -1.

Hotair temp: 365ºc, 70 airflow, quick 861dw
Chip removal was fast since i used 70 airflow, but then to solder chip back i used 40 airflow which take some time, that may had reflow the BB
I used a board holder that fit all MB body into a socket, hotair was blasted from bottom to top of the chip or the direction was toward board end to not cath any other chip on the sides

My question is: It is the BB CPU or can be BB PMU, or even other thing?
Phone worked fine before restore, no bootloop, only no sim network (keep searching)

Regards

boodala · 07-10-2018, 21:34

i thing problem vas in RF ic not BB cpu,its closest to audio module...

sn4k3PT · 07-10-2018, 21:48

Quote:

Originally Posted by boodala

i thing problem vas in RF ic not BB cpu,its closest to audio module...

Which one is that IC? IC Number?

I also used Kypton tape like this:

If is the BB CPU aka BB_RF the same chip must be used or i can buy one replacement and install it on place?

sn4k3PT · 08-04-2018, 02:17

Update:

Intel Model

Background:

1) Audio memo grey, no phone audio

2) Audio IC trace repair and reball

3) Audio works again but no cell signal

4) Try restore and fail at sending BB 80% (3utools)

5) Buy a preheater PPD120e

6) Remove that baseband cpu and reball

7) Phone show logo and go recovery, when restore error 4013 is shown.

8) It fail after phone reboot and the loading bar show, after a sec phone reboot to recovery again, but before that a horizontal line is show on lcd for a short period of time on top or bottom.

9) Tried reball that baseband 5 more times, same happens in all tries. I even use a thin tool to check weld position of BB_RF and on next try i position BB perfectly to not move when reflowing!

I have clean all underfill, have a lot of NC pads and only 3 connected pads rip off, lucky they are shared with other pads which are OK and also shared inside the BB_RF chip (I tested for continuity)

I tried restore without baseband chip in, same error happens. I start to suspect that i have other problem… The BB_RF reball comes out good as i use 3d stencils.

Block Image
From what i can see from the board side of the board, the first row of balls from Audio IC and BB_PMU look ok, but not sure where i can’t see.

PS: I used a heatshink on CPU everytime i apply heat to BB.

Any thoughts on that?

johnbaker26 · 08-06-2018, 18:58

Will it take iOS 12 beta 1? If not this rules out a baseband error (4013 can be a lot of stuff)

sn4k3PT · 08-06-2018, 19:16

Quote:

Originally Posted by johnbaker26

Will it take iOS 12 beta 1? If not this rules out a baseband error (4013 can be a lot of stuff)

Oh man, i follow your advice and used 12 beta 5, and for my suprise it pass the part where it fail with current stable firwamre! Goes up 80% and got error on baseband:

ninos22 · 08-06-2018, 19:32

Quote:

Originally Posted by sn4k3PT

Hello,

My question is: It is the BB CPU or can be BB PMU, or even other thing?

Regards

Before you decide to remove and reballing BB CPU do you confirm that was the BB CPU fault or BB PMU, or you just decide remove without confirm?

1st step before remove BB CPU is to check and confirm that BB PMU supplies proper voltage to the BB CPU.

sn4k3PT · 08-06-2018, 20:51

Quote:

Originally Posted by ninos22

Before you decide to remove and reballing BB CPU do you confirm that was the BB CPU fault or BB PMU, or you just decide remove without confirm?

1st step before remove BB CPU is to check and confirm that BB PMU supplies proper voltage to the BB CPU.

Before Audio IC iphone got network signal.
After audio IC rework audio was repaired but no more network signal.
If i restore i got error at 80% sending BB so i guess that was BB due audio ic rework. thats why i decided to reball BB.

The bad thing is ZWX don't have datasheet for intel version with the rails, the intel version is very incomplete

07-10-2018, 21:17	#1 (permalink)
sn4k3PT Junior Member Join Date: Feb 2015 Posts: 18 Member: 2353119 Status: Offline Thanks Meter: 1	iPhone 7 searching for network after audio ic replacement, need advice Hello, iPhone 7 had the problem with audio ic which i fix with the jumper, phone worked before it just don't get any audio. I replace chip and now audio works again. Problem is it keep searching for the network. Before people say, i know i may have reflowed the BB CPU, i didn't use a preheater, and i read all that info just now. The thing is i have IMEI, then i tried to restore to check the error, it stops at 80% when sending the BB at 3utools, error -1. Hotair temp: 365ºc, 70 airflow, quick 861dw Chip removal was fast since i used 70 airflow, but then to solder chip back i used 40 airflow which take some time, that may had reflow the BB I used a board holder that fit all MB body into a socket, hotair was blasted from bottom to top of the chip or the direction was toward board end to not cath any other chip on the sides My question is: It is the BB CPU or can be BB PMU, or even other thing? Phone worked fine before restore, no bootloop, only no sim network (keep searching) Regards Last edited by sn4k3PT; 07-10-2018 at 21:24.

07-10-2018, 21:34	#2 (permalink)
boodala Major Poster Join Date: Dec 2010 Posts: 40 Member: 1470195 Status: Offline Thanks Meter: 4	i thing problem vas in RF ic not BB cpu,its closest to audio module...

08-04-2018, 02:17	#4 (permalink)
sn4k3PT Junior Member Join Date: Feb 2015 Posts: 18 Member: 2353119 Status: Offline Thanks Meter: 1	Update: Intel Model Background: 1) Audio memo grey, no phone audio 2) Audio IC trace repair and reball 3) Audio works again but no cell signal 4) Try restore and fail at sending BB 80% (3utools) 5) Buy a preheater PPD120e 6) Remove that baseband cpu and reball 7) Phone show logo and go recovery, when restore error 4013 is shown. 8) It fail after phone reboot and the loading bar show, after a sec phone reboot to recovery again, but before that a horizontal line is show on lcd for a short period of time on top or bottom. 9) Tried reball that baseband 5 more times, same happens in all tries. I even use a thin tool to check weld position of BB_RF and on next try i position BB perfectly to not move when reflowing! I have clean all underfill, have a lot of NC pads and only 3 connected pads rip off, lucky they are shared with other pads which are OK and also shared inside the BB_RF chip (I tested for continuity) I tried restore without baseband chip in, same error happens. I start to suspect that i have other problem… The BB_RF reball comes out good as i use 3d stencils. Block Image From what i can see from the board side of the board, the first row of balls from Audio IC and BB_PMU look ok, but not sure where i can’t see. PS: I used a heatshink on CPU everytime i apply heat to BB. Any thoughts on that?

08-06-2018, 18:58	#5 (permalink)
johnbaker26 Junior Member Join Date: Jun 2017 Posts: 22 Member: 2729413 Status: Offline Thanks Meter: 15	Will it take iOS 12 beta 1? If not this rules out a baseband error (4013 can be a lot of stuff)