Iphone 6 No Display

[eDigitCom]

History

• No display
• No water damage No sign of physical damage

Fault Finding

• It Connects to iTunes
• Ammeter read 4.96V 0.39A
• ITunes looking for To get Trust to connect to iPhone
• Change screen with a know good screen- not solve

• All connectors look good

Question

Does this looks like back-light problem??

Where do I start to fault find with this type of fault??


Thanks

[Jessa_the_Professa]

The signature failures are either backlight anode line short or partial short or left bottom lcd screw bracket long screw damage.

[eDigitCom]

Thanks Jessa

Cannot see any lsd (Screws look very good) will upload small video shortly to show screws


I check the Diode reading on pin 2 of J2109 and read 0.564 Attached images

Checked diode reading at the bl filter and OK here also

Both not have a path to ground in Resistance mode

Does not have a partial short with a diode reading of 0.564

I did not take off the CPU shield to get at the rest of the circuit


Have to leave it for now -- 2;30am ??

[Jessa_the_Professa]

If it is not backlight anode line short, and you’re sure it is recognized in normal mode by iTunes and also not a parts problem then 8 times out of 10 an iPhone 6 with no image will be long screw damage. If you’re not sure about LSD then desolder the screw bracket to really see the bottom of the screw hole

[crea2k]

Id diode mode the lcd connector, this will give you an idea on what line you have a problem, otherwise you will just end up checking all of the usual suspects first and running round in circles.

[eDigitCom]

Jessa I made a small video

Could you look at it and in your view do you think it is screw damage At some stages in the video is not great has I am zooming in and out

The screw I think you speak off looks definitely different then the others

To me there is signs of metal at the end of the screw connector

Also you will see me using a tweezers pointing to some dirt on the connector

I find it difficult to remove this type of dirt. I be thinking they may act as an insulator to prevent proper connection with the flex cable. I use ISOPROPANOL 99.9% with a bud to clean

https://www.youtube.com/watch?v=U1csbAY6YDA&feature=youtu.be

Thank you

[crea2k]

What's going on with the digitiser connector ?, half of it's missing

[eDigitCom]

That is dirt There is one pin that is not the best

[eDigitCom]

I find it very difficult to remove this type of dirt ;(

See my comment about it above

See an image of the connector from another angle

[eDigitCom]

The MESON_TO_TOUCH_GUARD_CONN connector is missing and the TOUCH_TO_SAGE_SENSE_IN0 is not good And the earth connect missing also

So I agree half missing??


Would they stop the display from coming UP ??


I be thinking they would be a touch issue

[Jessa_the_Professa]

So the history is NOT “no sign of physical damage” you have a clearly damaged digitizer connector with flux in it. How did it become like this? History and visual exam are our most important tools. The history of damaged connector with flux changes the probability of faults dramatically.

how did it become like this? What is the real history? You’re right that a missing pin on the digitizer connector may not be related to image, but the story of how it became missing may be. Does this board have a replacement meson chip?

who uncovered the 1v8 components near lcd connector? You or someone else? What is up with the missing pin—is there corrosion at its pad from water damage or was it simply ripped off? All of these are important pieces of your repair picture.

[eDigitCom]

Yes I can see this now Not the best I agree to have missed.

The only think to say about this is I am very new to the inspection of mobile phone logic boards and I believe the more experience you have then the better you are going to get at it

To learn by your mistakes is very important


When I received the phone I was told by the customer that it had no display. I have now contacted the customer and I have informed her what has been found by the inspection of the board.

She told me she received it second hand and this is the first time it has been in for repair since she got it and it did not get knock or fall while she at it.

I not think the phone had its meson chip replaced I have included some close up images of it


The only component I uncovered was FL2024 to check the black circuity Jessa


Has I not touch the phone with any soldering then there had to be someone there before me



The pad is fine I show this in a close up image

Found no corrosion but I think maybe the phone was water damage. However the sticker was white and had not turned to red


I show two photos attached which I suspect that may have got water damaged


I also made another video with audio this time.. My first Anythink I say it in that may not be correct I would appreciate if you tell me

https://www.youtube.com/watch?v=yWctbfd_EHM

[crea2k]

Did it work after meson was replaced ?, of not you could well have bridged balls under the ic, or under ones next to it. Flip the board on it's side and bring your microscope to the edge of the desk, you should be able to look at some of the balls on the edge of the ic, which will give you a rough idea if they did a decent job or not. If it didn't work after meson was replaced that is a big clue.

[Sly]

Hey!
Did the customer ever used the phone? how could she have been using that phone with a messed up touch fpc like that.

Before investing real time on this, you already know you need to change the touch fpc, AND find why there is no image and repair that as well.

Just before going too far ahead, are you conformable replace that fpc connector, and is the customer willing to pay for a fpc replacement + what ever reason the phone has no image?

It is not my place to tell you how to pick your jobs. But from one repair shop to an other, when I look at that, I see a reasonably expensive, potentially time consuming, and complicated board repair with a large number of variables.

Just make sure this repair is feasible for both you and your client. Not all repairs are.

[Sly]

Hey Edigi,

I've just finished watching your video. You could check the anode lines for the backlight as well.

Also, a quick tip, when this first came in and you've seen itune detects it. An easy way to know if your dealing with no backlight would of been to reboot the phone while having a strong light flashing on the screen. If you can just barley see the apple logo you know right away that your dealing with no backlight.

If you're dealing with a no image situation, what are important rails that you could check in diode mode?

I would start by checking all the power rails for the lcd. I just finished repairing an iPhone 6s with prior screen replacement attempt. It had no image. The last guy must of have installed the screen while the battery was connected. There was a filter that was blown on a 1v8_lcm line, and no short to ground. I was able to find it quickly since the diode mode measurement for the line was open and should of been around 0.265V or something like that.