Should I try to repair the charging circuit?

Hi,

I got an iPhone 4 to repair. The issue is that it does not charge any more - at least not based on the screen.

When I plug in the cable (connected to the wall socket), the screen briefly shows me (1) the icon of the 31pin plug; (2) an electric flash; and (3) the battery icon with a blinking red area at the bottom of the battery icon, indicating that the battery is empty and needs to be charged.

Oh... I almost forgot: I also see a thin blue line along the screen.

In any case, the iPhone has not been used for months, so I assume it is as good as dead. However, measuring the pins of the battery I get 3.7 V. Hm...

I replaced the older docking port, since I saw that the owner had pushed back one pin in it, which I tried to fix but finally broke.

It seems to me that something is wrong with the charging circuit, maybe relating to a electronic component or chip.

Can someone help me?

Hi Garrett,

Thanks for your suggestion. Today I installed a new battery but the problem seems to be the charging circuit.

I can at least now switch on the iPhone (:-)) and can see that the new battery is still charged (about 30%). However, when I plug in the charging cable (connected to the wall socket), I don't see the flash symbol on the battery icon on the top right, i.e. the battery is not charging.

There is one disadvantage that came with the iPhone when I first opened it: It had been corrupted, meaning some screws were missing and also the retaining bracket for the docking port cable. However, I pressed on that connection to see if the issue could be that connection. But no changes after all.

Any other ideas?