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Go Back   GSM-Forum > GSM & CDMA Phones / Tablets Software & Hardware Area > iPhone ,iPod & iPad (Apple Inc. Products) > iPhone, iPad, iPod Hardware Repair

iPhone, iPad, iPod Hardware Repair Hardware Repair discussions for iPhone, iPod , iPad & Apple Products, help, guides.

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Old 03-08-2013, 22:11   #1 (permalink)
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iPhone 4S no WiFi - short finding

Hi !

I got a damaged iphone 4S , the cause was a lightning.
First, i have found that L12_RF was burned, i have removed it and tried to make a jump to see if i get at least a minimal signal, but no signal at all. Even if i put the phone over my WiFi Access Point.

Then, i have continued to find the problem, until i found that the 2 terminals of the antenna jack , J6_RF , are shorted!
It looks that the whole FL4_RF is shorted, every pin is shorted with every other.

I should now desolder FL4 to see if the short disappear or not, but.. if it is FL4 the problem, i don't know if it's enough to jumper it.

Anyone has an idea of what is used for ?

Iphone 4S_cropped.jpg
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Old 03-08-2013, 22:38   #2 (permalink)
HUM
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after removing fl4 still all pins short or not?
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Old 03-08-2013, 22:48   #3 (permalink)
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Removed FL4 just yet, no more short on J6_RF !

But.. still no wifi signal :-(

I check again the way J2_RF > FL10 > L1 > R49 , maybe there is a problem here...
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Old 03-09-2013, 20:36   #4 (permalink)
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This board is more damaged than what i tought.

FL10_RF was open, so i bypassed with a wire, now the antenna signal goes all the way to the U1_RF chip. But still.. no signal.

WiFi is not greyed, iphone show the imei, the wifi mac adress, the modem version, but i can't connect to wifi (don't see any AP available) and bluetooth to other devices.

Before unsoldering the U1_RF that it is a pain, what i can also check ?
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Old 03-11-2013, 21:39   #5 (permalink)
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Quote:
Originally Posted by laptopmd View Post
Hi !
Then, i have continued to find the problem, until i found that the 2 terminals of the antenna jack , J6_RF , are shorted!
It looks that the whole FL4_RF is shorted, every pin is shorted with every other.
it is normal. J6_RF is shorted for DC through FL4_RF and L14_RF. For radio signal there will be no shortage. And that is why all pins of FL4_RF are "shorted" (for DC ).
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The Following User Says Thank You to qwerty97 For This Useful Post:
Old 03-12-2013, 13:40   #6 (permalink)
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Quote:
Originally Posted by laptopmd View Post
Hi !

I got a damaged iphone 4S , the cause was a lightning.
First, i have found that L12_RF was burned, i have removed it and tried to make a jump to see if i get at least a minimal signal, but no signal at all. Even if i put the phone over my WiFi Access Point.

Then, i have continued to find the problem, until i found that the 2 terminals of the antenna jack , J6_RF , are shorted!
It looks that the whole FL4_RF is shorted, every pin is shorted with every other.

I should now desolder FL4 to see if the short disappear or not, but.. if it is FL4 the problem, i don't know if it's enough to jumper it.

Anyone has an idea of what is used for ?

Attachment 301938
This filter you show is for GPS not wifi/bluetooth and it is normal that it short.
Here try this if not fix try other antenna if same reball replace wifi module.
Before Open a Thread Search Here Hardware Solutions!
This is wifi antenna way and there is nothing else.
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Old 03-13-2013, 00:18   #7 (permalink)
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Thank you for your valuable help Wites ! Checked the way on your link, i have the signal from the connector to the wifi module. I had to bridge the white filter that was "open".

Ok, now i will check again all the voltages around the wifi module to be sure.. then i try to reflow...or change this module
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