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Revamped version of the iPhone 3G with faster processing speeds. Repair of this device is similar to the 3G, and requires simple screwdrivers and prying tools. Model A1303 / 8, 16 or 32 GB capacity / black or white plastic back.

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iPhone completely dead, shows no signs of life

My friend gave me an iPhone 3GS, he said he managed to get it to boot (not sure if he actually did!) however I’ve found that when plugged in (even overnight) it’s showing no signs of life, the screen is black and there are no sounds or vibrations whatsoever.

I’ve taken the device apart and measured the battery voltage, this was 0.16v so completely dead. I though this could have been the issue so to resolve this I remove the battery and charged it up using a bench power supply, it’s now reading 3.76v. I’ve reinstalled it into the phone but still nothing. (Maybe this voltage is still too low as even with the battery installed testing the battery probe points suggests it’s not charging)

I’ve checked what I believe to be the fuse for the battery and this has continuity, and I’ve checked to see if I have 5v on the dock connector motherboard test pads which I do.

I also checked to see if the dock connector voltage was present on the battery terminals, it doesn’t seem to be, could this be because the iPhone does not detect a battery?

I have also found that even powering the iPhone with no battery (through the dock connector) using an iPad 10W charger the iPhone shows no signs of life.

I have ordered a new battery, dock connector and digitiser. The digitiser is cracked but I’ve tried the phone without it to check it isn’t shorted. What are the chances of replacing these components fixing my issue?

does the iPhone need to detect a voltage above 3.7v before it will start?

Thank you,

Oliver

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Hi all, I’ve installed my new battery but the iPhone still seems to show no signs of life. I’ve double checked the battery and dock connector fuses and the voltage on the new battery and everything seems to be ok. I have also tested the motherboard with a dock connector attached and am able to read 5V on the motherboard test pads, I’m not getting any voltage on the battery terminals though. Could this indicate a bad power management IC?

da

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The phone requires a battery to boot. 3.7V should be enough to get the phone to start but I suspect your battery has no current driving capacity, even if it shows 3.7V and an iPhone requires a lot of current.

Start by trying a new battery to see if that solves your problem before changing the port.

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Thank you for your reply! I think my replacement battery has arrived today so I’ll install it this evening and post back my results! Fingers crossed it is simply the battery...

da

I’ve installed my new battery but the iPhone still seems to show no signs of life. I’ve double checked the battery and dock connector fuses and the voltage on the new battery and everything seems to be ok. I have also tested the motherboard with a dock connector attached and am able to read 5V on the motherboard test pads, I’m not getting any voltage on the battery terminals though. Could this indicate a bad power management IC?

da

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Before ordering the battery check the phones by external source by external power supply to found that the phone dead causes have only battery or other problems is.After long time not charging and connect with circuit battery amp is in sleep stage so you can also charge by any other outer charging live master charger and check if it start to works means you save your pocket i think.

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As Minho said,you need a battery. The battery communicates with the iPhone as well. You can theoretically have it plugged in with a battery,then take out the battery,and it may stay on. But to power on,it needs the battery.

for a battery to be that low,it seems it may have gone bad. Again,for the charging voltage to be present,the battery should communicate with the phone telling it that it’s there and needs to be charged.

Also, a very low battery voltage could be a sign of a short. But with how old it is,I’d assume it’s likely the battery. Let us know if it worked out for you!

For for the future,and amp Meyer is very useful. It reads the current flowing though it to the phone,and the voltage of the charger. It’s a usb plug that plugs into the charger on one side,and you plug the lightning cable in the other. Then it will tell you if the phone is pulling .6 amps or something,or if it’s 0.

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Thank you for all of your help and support so far! I think my new battery will be arriving at some point today so I’ll install it and give it a test.

if that doesn’t help I’ve read online that the Power Management IC can sometimes go bad, is this something that can be fixed easily or does it require removing all of the EMI shields? I have a hot air soldering station but I’m guessing a microscope and a lot of care and patience would make this task considerably easier.

Thank you,

Oliver

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I have to ask/comment...

The iPhone 3GS is hardly a device worth fixing on it's own, unless there is a specific reason for you to do so. If you have never really removed/replaced a BGA IC on an iPhone logic board, this is not the time to try. You'll want to practice on dead boards that have no value before attempting this on a device you apparently want/need to repair.

da

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Oliver sarà eternamente grato.
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