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苹果 iPhone 5s 于2013年9月10日公布。该设备的维修与以前的型号相似,需要螺丝刀和撬棒。可使用GSM或CDMA / 16、32或64 GB。颜色有银色、金色和太空灰。

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Crisis after U2 IC replacement

Hello...

I was experiencing problems with battery drain and overheating on a 5s, I was informed the U2 IC was in need of replacement so I thought I would have a go at changing it

I replaced the U2 but in doing so I knocked a couple of the nearby caps off (C500, C39), I have managed to replace the C500 but I am now in a bit of a pickle as the right hand side solder pad for the C39 has come off (this was my 1st attempt at IC replacement and I got a bit excited)

I am now totally lost as to where to go from here, the phone isn't booting and is stuck at the Apple logo with bright white screen, I'm unsure as to whether the problem lies with this missing cap or if I have maybe damaged something elsewhere in the process

Is there an easy answer here ?.. I'm a little out of my depth right now *hangs head in shame*

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Itchy, looks like C39 is used as line filtering since it is in the 1.8V SDRAM circuitry. Due to this, it could be preventing your phone from booting

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Thanks for the reply, I've had a serious look round the board Turkey and there's far more going on than just missing C39 ,.. I've no idea how this phone was even switching on before, no wonder it was cooking, there's multiple components missing.. filters, caps, resistors ..... I think it's probably best to give up on this board.... It was my 1st attempt at IC replacement, as the USB is now working (loading up Apple sign when I plug the cable in) , I might consider the "repair" a success.....lol.. minus the missing C39 (and pad).. replacing that cap wasn't really an issue until the pad came off...

If I was silly enough to continue on with this board, replacing the dozen or so missing components, I would still be in a pickle with the C39, I read peoples comments in many forums about jumpers, how do you determine where and when you can make jumpers ? and if a component is critical for phone operation and it can't be missed out, how do you go about fixing the issue ?

Do you just solder 1 side of the cap/filter etc to the remaining pad and then solder wire to the other end to connect to the next component in line ? .. sorry for all the questions but I'm eager to learn (like yesterday)

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You may not have gotten it to work, but I do agree with a success. I would consider it a great learning experience and you at least know when to call it quits. You may never use a jumper for a cap since it most often goes from line to ground (like the C39) that would shorten out the board. so each situation will require you to take a good look at the schematic

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I'm not sure if it's quits time yet, the phone was working before I replaced the U2, it was super hot and rinsing batteries super fast but it was working, which I find extremely strange looking at all the missing components and they are all over the place, from top to bottom, left to right... so I'm thinking perhaps it could run again if I can sort the C39 out (and I should able to replace a fair few of the other missing bits from a scrap board), .. also good practice for me...

With regards to theory, is there anywhere online you can recommend for me to gather some knowledge ? specific to schematics and understanding how to read a board.. and where I can find out what line to ground means ....lol

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email me and let me hear what you have thus far. My address is in my user profile. Just click on my Avatar

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