Why is my iPhone 4 not turning on unless it's plugged in?

Two main issues may have happened to your [URL=http://www.forevermac.com/category/apple... |iPhone]:

1) A Dead battery, which means that it simply won't even hold the date/ time. There's always a small amount of charge left in the battery that ensures it maintains the date/ time. I suspect this is fed by battery and not the actual charger- hence it won't power on properly from the mains. Replace the battery.

2) The Power Management unit is corrupted/ your OS is corrupted. Far more unlikely.

I would replace the battery to see if that fixes it.

i had this problem, I went out into town on the weekend, I ende dup quatting for a wee and it had dropped from my lap which was only 309cm off the floor.

It wouldn't turn on, yet I knew I had around 50% so I called it a night and got picked up. Thinking I was a little bit too drunk I thought id put it on charge in case it was actually dead..

It turned on once I put it on charge! I could not tell you how happy I was with it! but then I realised my phone was saying 100% then I knew there was something wrong, I took it off charge and it turned off this did my head in!

I pressed really hard on my battery so it could fit back in place and surprisingly this had worked my phone was freely working off charge! I was very happy! until today. it fell off my lap and down the side of my seat in my car, (which isn't far down) and now It wont work unless charging, iv tried pressing down on my battery and it works for about 5 minutes and then switches off again! :l APPLE NEED TO SORT THIS OUT! but yeah if anyone else having the same problem just try and put pressure on the battery and push it down as hard as you can so it fits back in place. Hope this helps:)

Alexa buy a $5 battery problem solved

By squeezing the lower left corner you are excerting pressure on the battery connector which probably has a dry joint. Take the back off and put some card over it, when you slide the back cover back on it , it will put pressure on the connector and hold the joint closed.

Steve...

I have the same problem too, but I think another factor that causes it is the memory. Mine's almost full which I think causes also the lagging that prevents the display to turn on. Try deleting some apps to free up your memory storage.

When you remove the battery, there is a good chance of breaking or cracking the six solder joints under the piece the battery plugs onto...depending if some or all get broke, you will have different power issues...be %#*@ careful when unplugging the battery!!!! Wish that was in the instruction I read..trying to put one back on now

You might also want to take a look at this before you try messing with your hardware.

https://www.payetteforward.com/why-does-...

I recently replaced the screen on my iphone 4 verizon phone, it would only turn on if charged though a wall port, kept searching for service and read 100% battery. when unplugged it would immediately turn off and could not be charged by my mac, also the screen would freeze every minute or so and automatically restart... I took the back off of the phone, took out the screw for the battery connector and pushed REALLY hard on the connector piece, like white thumbed myself and now..... Presto! service restored and it holds a charge. Thank you for this answer!

i squeezed the bottom backside of my iphone 4 the it turned on but my screen still flashes once in a while.

My daughter dropped it in the toilet, so I took it apart to let it dry out. When I put it back together, it would only work plugged in. I knew the battery was good before she dropped it, so I knew that wasn't the problem.

I tried the idea I read here about pushing on the connector, and I felt it move into place better. Problem solved. Thanks, guys!

I dropped my phone in the toilet and I'm having the exact same problem and nothing has helped. My iphone has been through a lot and survived so i didn't think this would be a problem.......... It is!!! Unfortunately my power button broke earlier this week, my home button did this before and fixed it's self so i wasn't worried. But now I'm giving up it is seriously broken.............. Anyway try holding the power button and home button at the same time this has help me with other problems before. Give that a try if nothing works it's most likely broken.

I had the same things . So now ur batt is connecting to ur anthena of network . When ur batt is broken ur anthena also broken . So this is PSU prob ( POWER SUPPLY UNITS ) now ur PSU is bend . When u charge ur phone PSU will give 1 power to turn on the phone . I dropped my phone on the floor it will die . So u need to repair ur PSU prob and also change ur batt for the good result!