iPhone 4: wifi not working after middle frame replacement

[jacoscar]

I'm trying to repair an iphone 4 dropped from the 4th floor; it had the middle frame bent and the battery and the LCD to be replaced

I bought a new middle frame, LCD and battery and reassembled it from scratch; when I turned it on I realized that the wifi does not work; it doesn't find any network

The logic board had a couple of broken nut (the smallest one always broke when I performed an lcd replacement but has never been a problem, see the picture) so the metal plate is only kept by three screws; I also tried cleaning those screws with isopropyl alcohol with no success

What else should I check?

[DRPCs]

Be careful when reinstalling the 4.8mm screw, as that's the one that grounds your wifi. Make sure that it's screwed in tightly and straight, it's the one circled in teal coloring.

[jacoscar]

I was aware of that; I already removed and tightened the screw several times, also cleaned it with ip alcohol

I was wandering if the problem could be the middle frame itself or the battery or even one of the missing nut (and relative screw) (left orange and yellow circles in your picture)

I also have weak cellular signal


Anyway I don't understand the grounding thing; I checked the frame with a tester (ohmmeter) and found out that it's all connected together even if there are the plastic things that divide it in three portions; also the metal plate that cover the ribbon cables is electrically connected to the frame, and so is the 4.8mm screw

[iRevival]

If you are missing the small metal piece that the screw goes through then you wont have any wifi signal at all. The shield is black and where the 4.8mm screw goes there is a silver colored metal ring. Make sure that you have that on there.

[jacoscar]

If you are missing the small metal piece that the screw goes through then you wont have any wifi signal at all. The shield is black and where the 4.8mm screw goes there is a silver colored metal ring. Make sure that you have that on there.

I have the metal piece,
How con I test if that connection works?


There is a little mark on the contact point where the metal piece is supposed to sit...

[jacoscar]

Could anyone do me a favor and try to remove this screw from his iPhone 4 and see if wifi works anyway?
https://www.dropbox.com/s/e1pdw1zwrj...%2013%2014.jpg (the left orange one)

[hcgaloi]

If the iPhone can recognize WiFi standing very close to a router then most likely is a grounding issue. Hope this help...

[jacoscar]

If the iPhone can recognize WiFi standing very close to a router then most likely is a grounding issue. Hope this help...

It can't do that either, even if it's very close to the router

[DRPCs]

Could anyone do me a favor and try to remove this screw from his iPhone 4 and see if wifi works anyway?

I did two comparisons. One with the 4.8mm grounding screw, along with the one you wanted removed. WiFi signal was lost when removing the 4.8mm screw, but not the 1.6mm screw.


(sorry about the AssistiveTouch in the way, my client has a non working home button)

If you're out of options, you could try ordering a WiFi antenna maybe?

[jacoscar]

I did two comparisons. One with the 4.8mm grounding screw, along with the one you wanted removed. WiFi signal was lost when removing the 4.8mm screw, but not the 1.6mm screw.

Attachment 621589 Attachment 621590
(sorry about the AssistiveTouch in the way, my client has a non working home button)

If you're out of options, you could try ordering a WiFi antenna maybe?

Thank you very much for the test

As for replacing the wifi antenna, isn't that just a piece of metal?

I'm starting to think that my problem is something on the logic board, such as a broken or missing fuse or coil, because if it was an antenna problem I would catch a tiny little signal when close to the router

[iRevival]

That shield is the antenna. You could try replacing it to see if you regain your signal. As long as it isn't grayed out then I'd give that a shot. Wouldn't get my hopes up too high though.

[hcgaloi]

if you're heading toward trouble shooting the logic board, forum.gsmhosting.com has tons of experts whom may be able to help you. Good luck

[jacoscar]

I check out that forum but I don't have the equipment to test the logic board so I brought the phone to a repair shop in London
They weren't able to find the problem and said the ICs are fine
Now the phone is being checked at another shop; I hope they'll have more luck

[jacoscar]

The second shop told me they weren't able to repair it too; the problem is that now the wifi option is greyed out, and bt and gps don't work anymore....

Since they didn't charge me, I don't know if I should go and claim my gps and bt back...