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04-14-2015, 17:35 | #1 (permalink) |
Junior Member Join Date: Oct 2011
Posts: 39
Member: 1676326 Status: Offline Thanks Meter: 1 | Iphone 4, logo 1 sec then off I was testing a new screen for my iPhone 4, and after reinserting the battery the screen flashed with Apple logo for 1 sec and then the phone turned off. It is dead untill I remove battery and then it does the same. Without battery and into the computer port, the screen does the same. I put the motherboard into another iPhone, but the problem is the same, so I guess the problem is with the board/software. I can put the phone into DFU mode and iTunes finds it but without serial and screen only show a logo shortly and then turns off. When trying to restore I get an error 21. Please help. |
04-15-2015, 16:00 | #4 (permalink) |
No Life Poster Join Date: Jan 2013 Location: lebanon
Posts: 601
Member: 1869842 Status: Offline Sonork: 100.1625473 Thanks Meter: 186 | I was searching to help you solve your problem is that error21 is a hardware problem due for a non well fixing connectores or a dust that need to be cleaned and from a bad assembly I think you need to dissamble your phone again and try to assembled correctly that what's appeared with me by searching to solve your problem Please try and post result |
04-16-2015, 04:44 | #6 (permalink) |
No Life Poster Join Date: Jan 2013 Location: lebanon
Posts: 601
Member: 1869842 Status: Offline Sonork: 100.1625473 Thanks Meter: 186 | Many problems caused for error 21 please read from this linkhttps://www.ifixit.com/Answers/View/...tting+Error+21 |
04-19-2015, 09:35 | #8 (permalink) | |
Junior Member Join Date: Oct 2011
Posts: 39
Member: 1676326 Status: Offline Thanks Meter: 1 | Quote:
http://gsmresolutionworld.********.d...s-problem.html All has perfectly fine connections and no shorts. | |
04-28-2015, 18:44 | #11 (permalink) |
Freak Poster Join Date: Apr 2015 Location: Jerusalem, Palestine
Posts: 209
Member: 2386012 Status: Offline Thanks Meter: 94 | When an iPhone turns on for a second and turns back off, it means it's not detecting the battery. Try to replace your battery. It can be from a damaged battery cable. If that doesn't work, then battery connector needs to be replaced and soldered. Last and least common, IC needs replacement.. Hope i helped. |
04-28-2015, 18:53 | #12 (permalink) |
Junior Member Join Date: Oct 2011
Posts: 39
Member: 1676326 Status: Offline Thanks Meter: 1 | Thanks for the suggestion, I have tried with two different batteries. No go. Wouldn't the phone turn on when no battery is inserted but connected to power? When measuring on the red points what should my multimeter be set to measure? Resistance? What is buzzer mode on the drawing? |
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