14 Replies Latest reply: Feb 11, 2011 3:07 AM by Amylittlehands
Amylittlehands Level 1 Level 1 (0 points)
Hi there,
I've been trying to repair my iPhone and have a feeling the battery is faulty, I was wondering if someone could supply me with the terminal readings for the battery?

what I mean by it not turning on is that you can boot it up ONLY with it plugged into the wall charger, then when I turn it on the apple logo appears as normal then after say 10-15 seconds the phone switches off, when I unplug the USB as it's showing the apple logo it switches off instantly. My dad reckons there's not enough power to go through it (he's good with technical things) therefore I think I need to replace the battery if the terminals aren't reading and I might need to change the dock connector.

My dad tested the battery and it states the right voltage amount but I think he said that one or two terminals aren't reading, could this be the problem?

- Amy

iPhone 3G, iOS 4, I've tried to do hard refresh etc ... I know it's not any of those reasons
  • Risky63 Level 1 Level 1 (20 points)

    There are 4 terminals on an iPhone battery. You should measure anywhere between 3.5 - 4.2 volts between the + and - terminals. The other 2 terminals are a temperature sense line and a data communications line - you shouldn't measure any voltage on these if the battery is behaving normally.

    It sounds like you need to restore your phone with iTunes, I hope you have a recent back up. I had the exact same problem last week and restoring it fixed the problem. If you need any help get in touch.
  • Amylittlehands Level 1 Level 1 (0 points)
    Thanks for the reply, I don't mind losing my data as I'm going to set it as a new phone anyway. The thing is that my iPhone won't connect to the computer, and I can't get it into Recovery/DFU mode. When I plug my iPhone into the wall charger and a press the power button the apple logo shows for about 5-10 seconds and turns off, even during the time the Apple logo appears and I unplug the phone from the wall it turns off instantly. If I plug it into the computer and press the power button, nothing happens. I've also tried hard refresh, everything I can possibly do.

    I forgot to mention that my dad replaced the back and front assembly but he made sure he connected it all correctly, took him ages, I think the battery or dock connector has fried in the process though.

    Do you think if I took it back to Apple (My warranty is up) and asked for a cheap refurb do you think they will?

    If not I'll have to replace the dock connector and battery.
  • deggie Level 9 Level 9 (51,185 points)
    You can do an out-of-warranty replacement but I wouldn't define it as "cheap". It is $199 in the US.
  • Amylittlehands Level 1 Level 1 (0 points)
    $199? Surely that'd a bit expensive for an iPhone 3G 8GB refurb? I'd think that'd be an iPhone 4 Refurb price?
  • deggie Level 9 Level 9 (51,185 points)
    That is an out-of-warranty service replacement price at the Apple Store and you will have to turn yours in. They don't sell (retail) refurbished iPhones at the brick and mortar Apple Store, nor any at the online store currently.

    You can currently buy an iPhone 3GS from AT&T for $49 with a new contract.
  • Risky63 Level 1 Level 1 (20 points)
    OK, with the phone off, plug the cable into the computer, then keep your finger on the home button while you plug the cable into the phone and whilst keeping the home button pressed press the power button, this should get you into restore mode and then iTunes will detect it and you can restore.

    There is nothing to fry in the dock connector and the fact that the logo comes up when you plug the cable indicates that the battery and dock connector are functional. Hope this helps.

    Let me know.
  • Amylittlehands Level 1 Level 1 (0 points)
    Thanks for the reply again, I've tried this method numerous amounts of times, even of different computers with latest iTunes, I kept my finger on the home button for a max of 3mins last time, still no luck. The fact remains that if I turn the phone on while plugged into the wall charger it shows the logo and switches off, if it's plugged into a computer it does nothing, tried DFU & recovery mode but nothing works. I'll let you know if I ever fix this issue. Cheers
  • Amylittlehands Level 1 Level 1 (0 points)
    Also I thought I should let you know why i think the battery/dock are broken. Many other people have this problem when replacing the back housing to their iPhone, my dad said the battery was a bit squishy when he took it off (Sounds silly I know). People suggested the dock connector isn't allowing enough electricity through to fully power the phone, which I think is a plausible suggestion. Also, for some reason the screw under the 'Do not remove' sticker doesn't fit properly, this is because of the new back housing (not drilled exactly the original) so I'll be getting screws from the manufacturer.

    I sure hope I can get my baby working again! Little iSable is waiting haha!

    I'll let you guys know if any changes occur!

    And thanks for the help so far
  • Risky63 Level 1 Level 1 (20 points)
    OK, now that you offer that information, I'll ask why you changed the rear housing? The housing you have got obviously isn't genuine. That screw under the "Do Not Remove" sticker actually pulls the circuit board down tight onto the -ve battery terminal and what is probably the data connection line of the battery. I still think that the docking connector is OK, unless the ribbon or socket is damaged. I would focus on getting that screw to fit properly. The battery is a Li Polymer cell, they are a bit squishy normally as long as it's not puffed up. If the fault was with the battery or connector you wouldn't get the logo up on the screen at all. Can you put the old housing back on?
  • Amylittlehands Level 1 Level 1 (0 points)
    Thanks for the reply, I had to change the back because it was cracked and split all the way through so lint was getting in my phone. I contacted the supplier for my casing and told them that the screw holes are too big and my original screws fall into the holes and are too small, I guess I'll have to buy a screw set off them, I haven't bought the dock connector yet but I bought a higher capacity battery (Had troubles with the phone losing battery too quickly, phone is quite old) but I'll have to wait a few days until new screws arrive, I'll keep you updated.

  • Risky63 Level 1 Level 1 (20 points)
    OK, so you have a non-genuine battery, that is what is causing all your problems. I mentioned the data communications line, the iPhone uses this to validate the battery before it will turn on. Put the old battery back in and restore and you will probably find that the battery life is appreciably better, or if you or your dad are suitably equiped, take the battery terminals off the old battery and fit them to the new battery, (they are on a flexible pc board), but be careful as getting it wrong can cause serious damage.
  • Amylittlehands Level 1 Level 1 (0 points)
    I haven't installed the new battery, just bought it
  • Amylittlehands Level 1 Level 1 (0 points)
    Okay so updates:

    Dad replaced battery (he confirmed it is compatible)
    Still don't have the screw for logic board yet

    Before my iPhone wouldn't turn on when plugged into PC, or when it gets unplugged from the wall charger. However today I can put it into DFU mode on my PC BUT as soon as it starts restore the phone switches off (I know this because the computer makes the sound when something is disconnected). I personally think this is still because of the missing screw which isn't giving the iPhone enough power to even restore, also my dad noticed an inductor that well off the dock connecter, my dad managed to jump wire it so that isn't a problem now I think. I'm just waiting on screws now and hopefully it'll work.
  • Amylittlehands Level 1 Level 1 (0 points)
    Still no luck, replaced battery, dad cleaned every port known in the iPhone. However the phone shows the charging red battery with a lightning bolt underneath it, however when I unplug it from a power source it switches off instantly. I've left it on to charge overnight through wall charger and no luck. I've tried everything possible such as DFU mode (When it starts to restore it makes a screeching noise, shows a white screen, then apple logo then turns off) so can't restore it. I've tried doing hard reset etc ...

    Waiting on dock connector assembly, if that fails then I'll have to sell it on eBay as faulty and save up for a new one Wish me luck.