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Shane Meendering
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Why doesn't my iPhone 3GS recognize SIM cards?

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I received an iPhone 3Gs locked. I unlocked it to find it doesn't recognize any SIM cards, so I am unable to get cellular service from any provider in my area. I've got three options in my area. LongLines Wireless, iWireless, and the dreaded AT&T. I have SIM cards from LongLines and iWireless. Here's the kicker. I also have an original iPhone that I'm currently using. Both SIM cards work in the original iPhone. I've done the standard restart/hard reset/reset network settings/restore/ect. This leads me to believe it is a hardware issue with the phone. It's worth mentioning I received this device from a source in South Korea. I reside in the US. This indicates the baseband could be different than others. The iPhone could be setup to broadcast at a frequency different than the standard frequency range used in the US. The only blaring hole in this theory is that the phone came with an AT&T SIM card that was presumably the correct one for the baseband. This one works with the original iPhone as well. This leads me to believe the issue could be with how my iPhone 3Gs reads the SIM cards. My question then becomes "Is the SIM read by the logic board, or is there a separate component that performs this task and passes it on to the logic board?" I really just need to know which component I need to buy to get it to work with cellular networks again. It's my understanding it did work at one time. Any help you could give me would be greatly appreciated.

Edited by: Shane Meendering ( ) , bushing ( )

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bushing
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This has to be a problem with the SIM card slot, which is soldered down to the logic board. It's possible that it's a mechanical problem -- you might be able to open it up and discover that the card-detect switch is failing to detect SIM card insertion. Otherwise, you're going to have to replace the logic board.

Thanks so much. That's what I was looking for.

Shane Meendering,

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the problem can be in the golden notch that makes the phone detect the sim when it is properly pressed by the sim card make sure it isnt defected or broken you can make it press that notch by soldering plastic on the sim tray to give an extra push to the gold notch

Hi, I have iPhone 4, after water damage. I cleaned all the parts I could, left the logic board in special Alcohol for some hours.. but have no signal appears in the phone. sometimes I have signal for a while, then it turns back to no signal. Is there any option to open the slot so I can take a look and maybe clean it a bit? Plus - What could be the problem? thanks

Shai,

there are several posts on here about the antenna and finger grease.. make sure that is clean. if it was a sim problem surely it would say no sim on the display..

pollytintop,

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Hello shai I dont exactly know the technical reason of why your iphone doesn't show signals after being water damaged.the good thing is that the phone shows signals some times now there might be some problem with the sim tray slot if you check the sim slot internals there is a gold pin at the end of the slot which is pressed by the sim tray and to force the hardware to start searching for a sim card try pressing gently on the head of the sim tray and keep pressing until the phone shows signs of signal since the sim tray is small take a small rubberized pin and force the sim tray at the middle ( all the force is for the golden pin push ) if that doesn't work then try sending it to a repair shop. Since the phone is water damaged

This is merely a theoratical suggestion if it works thumbs up for you I don't take any responsibility of the damaged caused to your phone by following this suggestion

Good luck :)

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See step 15 of the iphone 4 Teardown to understand the Golden pin iPhone 4 Teardown

its for the sim not detected problem i don't get what you mean

guru,

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dillysano
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you need tyo restore your phone to factory settings reinstall apple iTunes on a new sim with tmoile or usa at&t sim then after you've synced the iphone with the computer and iTunes replace your old sim and it will work fine heres the method step by step - happens a lot with jailbroke phones

http://dillysano-mymakemoneydiary.blogsp...

Update

The reason this happens is just so you know , the os system has been updated and your jaikbroke phone isn't being regognized with the right settings , this happened after a apple update a year or two ago . The actual logic behind the solution is simple . You must find a sim that preferably is a contract which will have data plan options you don't need to buy the data plan of them your just borrowing it so it can regognize your old sim that suddenly stopped working . use a friends sim aslong as its contract remember it has to e the same network the phone was originally on which I find mostly is t mobile in uk or at&t in the us .

Factory reset your iphone then with old sim not regonized it should say activate or a message along those lines . insert the borrowed contract sim and your usb to your iphone and laptop making sure you have a up to date iTunes installation on your laptop it will start the process on its own once plugged in just wait a good while may need to replace wire a few times but it will start to sync with the borrowed sim .

After synced and all finished your phone will be working again with the borrowed sim now add your old sim it can now recognize the operating system and network provided settings allowing your old sim to work again resync through usb and then give back the borrowed sim it will be fine now.

Full method in detail

Edited by: dillysano ( )

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