Iphone 4 replacement screen not working

[notallbad]

Replaced screen and just comes up with backlight.
Tried a different screen and put the old one back on which did work just cracked but not working now.
No display and no touch screen response.
Connects to pc via cable, detects iphone and shows the empty folder.

Vibrates or 'rings' depending on position of vibrate/sound switch when charging.
Whilst charging just vibrates or dings every 6 secs or so.

Ideas anyone please. Appreciate it!

 

[scifan57]

If your old screen worked and the new one doesn't, it's likely that the new screen is defective. If you can, take it back to wherever you bought it and ask for a refund. Was the replacement screen a genuine Apple replacement screen? Third party replacement parts are much more likely to be defective.

 

[notallbad]

Neither screen is working.

Sure no damage has been done as I am very careful.

 

[scifan57]

It's possible that you inadvertently caused some damage that's not immediately obvious. Have you checked the cables and connectors to make sure there's no damage to either? Check the motherboard to see if there's damage of any kind.

 

[notallbad]

Quite sure the cables are fine and not over tightened any screws or replaced in the wrong places.

What or where would I be looking on the motherboard for damage?

 

[scifan57]

Anywhere near where you were using your tools would be a good place to start.
If you have a repair shop nearby you could take it there and ask if they can run a diagnostic on your iPhone. It might help narrow down the cause of the problem.

 

[notallbad]

I only ever use plastic spudgers or the like so not to short anything out and careful not to lever against other components/parts etc.. which would break/snap/crack anything. Of course, I am no expert but have repaired a couple of other iphones in the past for friends/family with no issues.

Has anyone ever seen one with the same symptoms? And more to the point, have they been able to repair it?

thankyou for your advice, are they likely to charge for the diagnostic?

 

[scifan57]

Possibly. Apple doesn't but you can't take it there as you've opened the iPhone and started the repair. Your best bet is to call local repair shops and ask if they charge for a diagnostic.

 

[notallbad]

Have ordered another screen just to be absolutely sure but pretty sure its not the problem.

Odd that theres no solutions anywhere for this but lots of people reporting the same/similar problem.

 

[notallbad]

Received new lcd assembly and a locked logic board just to prove screen etc working, I know the logic board is no good for much else as its icloud locked.
Put the old logic board back in and problem persists, not powering up, itunes recognises the phone and done a restore and update and sync but still no screen etc...

 

[scifan57]

Maybe the connectors are damaged? Have you checked where the screen connects to the logic board?

 

[notallbad]

Thanks, have checked both lcd and touch connectors on logic board and look ok.

 

[notallbad]

So having convinced myself its the logic board at fault I decided to remove the soldered topshield for further inspection to reveal some water damage.
Theres a small black component with F2 printed on it that was easily removed whilst cleaning. Any ideas what it is for a suitable replacememt. It was located between 2 coils (just above the Toahiba I.C) and in the middle of the 3 larger case style caps in the middle (between the 2 large I.C's).

 

[scifan57]

So having convinced myself its the logic board at fault I decided to remove the soldered topshield for further inspection to reveal some water damage.
Theres a small black component with F2 printed on it that was easily removed whilst cleaning. Any ideas what it is for a suitable replacememt. It was located between 2 coils (just above the Toahiba I.C) and in the middle of the 3 larger case style caps in the middle (between the 2 large I.C's).

There are no replacement parts available for individual components on the logic board. You'd have to replace the entire logic board.

 

[notallbad]

Ok, this technical detail is clearly beyond the knowledgebase of this forums members so shall whip one out from another working-i.e icloud locked or non-working board and test for its characteristics.
Thanks