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 / 16 or 32 GB capacity / black or white plastic back.

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3GS won't power on after reassembly

Hi there,

I recently acquired a hand-me-down 3GS, which was in pretty bad shape physically and electronically. When I first got it, the phone had an issue where the audio would garble up at random times after a hard reset, usually after an app or call comes in and when audio kicks in. This is not limited to using the speaker/earpiece/headphones only, but any audio signal that is being played. Once this 'garbling noise' starts, it will eventually cut off and all audio is disabled from that point onwards until a hard reset is performed.

Obviously, this was quite annoying as I had to complete my phone conversations by SMS after being cut off, and my phone would not ring upon any incoming events. All other functions of the phone work as they should, and all buttons are working fine.

I did some Googling, and found almost nothing related to this problem (mostly related to bad headphone jacks, etc.). However, I did manage to stumble across a forum describing this issue as being caused by a bad audio chip on the phone's motherboard. Someone was able to address this issue by doing a heat reflux but this was not documented well enough for others to replicate.

Deciding that the phone was worthless in terms of functionality, I cracked open the phone, had a look inside and took off the RF shields covering the ICs to look for this audio chip and found it to be fine with no visible hints of anything heating up or burning. I gave everything a blow with a blower, cleaned up some gunk and closed everything back as it was. Phone booted up and audio issue was gone, for a few days. Beyond which I had to literally drop the phone on a hard surface to get the audio running again.

Once again, I opened the case, cleaned up what I could on all contacts and closed everything up and all was good to go for quite a while. This was when I thought I had fixed the issue and wanted to refurbish the phone as new after getting familiar with the phone's innards over the weeks. Took it apart again to have a final look but upon reassembly I noticed that the LCD ribbon had been damaged due to the stress I may have accidentally placed when reassembling the phone multiple times. This caused the LCD to only display when I put pressure on the ribbon, although backlight is functioning at all times thus showing a totally white screen when the phone is on. Digitizer is registering my unlock swipes as well as I can hear the phone play the unlock sound when it does.

Finally, down to my issue: after pressing on the LCD ribbon to get it to display a few times, the ribbon gave up and all I got was a white screen. I remember that the battery was very low, so a few moments later I could only get to the red battery screen where the phone would not power on and indicate that a charge is necessary to proceed. Was frustrated as $%@% then and left it for a few days.

I ordered a new front assembly (LCD, digitizer, earpiece, proximity sensors, menu button, etc.), a new chrome bezel, new sleep, volume and silent switch hardware and also a new rear case and now am ready to proceed with getting the phone up and running. Tried turning the phone on since I last left it and only the backlight came on for a few secs, and went off again (battery low, must charge to turn on).

I plugged it into a few different chargers, even my computer for hours each time and although the back gets very slightly warmer (indicating that it is indeed charging), I cannot power the phone on (LCD backlight doesn't come on anymore). Suspected the LCD was dead so put in my new front assembly and still no luck. Tried holding down power and menu buttons (hard reset, have gotten very good at that and can do it with one hand now), plugging to iTunes, changing cables, but still no luck. Phone does not power on and iTunes does not detect.

I understand if this question is probably one of the longest you've read through and I truly am grateful if you've made it this far. I hope someone would be able to at least share their similar experiences so we can discuss our options together, or if someone has already solved an issue like this before and can shed some light, those would be greatly appreciated.

Many thanks in advance!

Answered! View the answer I have this problem too

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in your long list you don't mention a new battery, or have I missed that? Great question though! +for the excellent detail.

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NO.1 thing to try here is a new battery. Once they get too low you can't charge them and they are no longer any good to you.(they'll take longer to charge, won't hold charge etc) Once you have a new battery then you know that one thing is certain..you have power. Your computer will not recognise an iphone with no power, (bit like a handshake..you need 2 hands, or in this case 2 powered items) Get the battery and then you can re re re assemble the phone and we can troubleshoot from there.

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Hi I would recommend a DFU restore if you have not already tried.

Be aware this will delete all data.

To perform a DFU restore

1. plug phone into iTunes

2. Whilst phone is off hold down power and home button for 10 seconds

3. let go of power button but keep home button held down

4. Do not let go until iTunes notifies that the phone is in recovery

5. Follow the steps and it should restore the phone and resolve the issue

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Hi Paul,

Thanks for your help, but I've tried that a few times and have just done it again with no luck. iTunes is open, and not detecting the 3GS at any stage. Verified everything else to work by plugging in my iPhone 4 after that with instant recognition in iTunes.

It seems like my issue is related to hardware. Upon further reading I am now contemplating replacing the battery and headphone jack/buttons ribbon cable assembly. However, if it still does not work I will essentially have a whole new 3GS minus the logic board.

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ctrlaltdel86 will be eternally grateful.
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