CDMA version of the fourth generation iPhone. Repair is straightforward, but the front glass and LCD must be replaced as a unit. 16 or 32 GB / Model A1349 / CDMA compatibility.

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iPhone 4 CDMA not turning on without being plugged into charger.

I have an iPhone 4 CDMA Verizon that had a a broken digitizer but LCD was working. I purchased a replacement digitizer and LCD and replaced the screen with no issues. BTW, I have replaced 20+ iPhone 4 and 4S screens with no issues.

When I went to turn on the phone it wouldn't turn on. I double checked the battery connector and everything was correct. I then plugged in the phone to a wall charger and the phone booted up. I unplugged the charger and the phone turned off.

I suspected the battery could have been bad but the phone wasn't experiencing these issues before screen replacement. I swapped another known good battery in and the phone is experiencing the same issues.

I have disassembled the phone and double checked everything and still have the same issue. I read that it could have been a battery pad port that was damaged but I was unable to see any damage.

Anyone have any tips or suggestions?

Thanks

Answered! View the answer I have this problem too

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those battery contacts are pretty easy to loosen when you lift the battery out..I'd take a good look at them where they connect onto the board. I've had one or 2 cause a problem like this.

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Battery issue usually consist of the phone dying quickly, and charging would either be faster than usual or weird in a sense you have not noticed before or you charge it for 2 hours or so and it dies in an hour.... but unless the phone is water damaged then the iphone does not come on if there is no battery honestly speaking so that rules out battery...

now when you said you plugged it in and it booted then plugged it out and it shut off... do you have another iphone? perhaps you can charge the battery in that iphone and see what happens...

i think its possible that the port is bad because if you get the same response from a good battery something is wrong at the connection because it turns off immediately after you take out the ac power that means the other power source is not supplying the phone AT ALL and it was strictly depending on the ac power... if you have an analog or digital multimeter you can test the connector to see how much voltage is coming out at the pins... this way you can know for sure...

this may just be an idea and last resort but the promixity sensor could be an issue too... if you are pressing the power on button and the iphone does not come on yet it turns on when plugged in, the power button could be defective and the whole proximity sensor has to be replaced... try getting it on when you can and see if you can get it to sleep/ wake...

i hope this helps... just my suggestions

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Thanks for the response. The phone has no water damage at all. All sensors are white.

Regarding the power button, it does work because it will sleep and wake when powered from AC power.

To check the voltages, can you tell me what pins I would need to test and what voltages I should expect to see.

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the outer pins are ground and voltage with the bottom being voltage output and the one on the top being ground... iphone 4's charge at approx 2.8v so anything lower than that and you have problems...

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gtcoodyscoops, check on your values. Not sure where you get the 2.8V for charging from....

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I think she's referring to the battery itself..it won't charge if it has less than 2.8mav charge left?? not that the input has to be 2.8v?

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Ive seen this problem in two different scenarios on a regular basis.

The first being a phone that has had moisture damage in some way. You say that the phone does not appear water damaged so I can rule that one out.

The second situation would be that the battery socket on the motherboard is damaged. Ive seen many a connector have one or two of their pins come loose from the pads on the board. This makes it very hard to diagnose because it will appear as if the connector is still attached when one or two of the legs have broken free. To rule this problem out grab a magnifying device of some sort and tweezers. Use the tweezers to gently poke and prod the connector as you look for signs of movement from the pins coming out the back. If even one of them moves slightly you may have a issue. If that is the case getting the pins reconnected properly will involve soldering them back to their pad.

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