iPhone 4 recharges if turned OFF but wont charging if ON

The 1st tragedy was my Dock Connector & Loud Speaker Buzzer were burnt bcoz of overnite charging. 1st scenario was, I slept over my iPhone on my bed. My phone slips under my body while im sleeping along the night & i guess is overheats along d nite. On the next morning i smells burnt toxic gas & i realized that my dock charger cable were merely MELTED, same goes to my Dock Connector. But thank God that my phone was 100% charged and still ON. After that I tried to recharge it again just to test it, & its NOT CHARGING & my iTunes dont detects my phone. So then, that was d last 100% battery dat i used my phone b4 my phone went DEAD.

After dat, i replaced d damaged Dock Connector & Loud Speaker Buzzer coz i assumed dat my phone was fine other than these 2 damaged parts. Since my battery was 0% & d phone was OFF, so I tried to recharge it using d newly installed parts, and IT CHARGES!

BUT! after 4-5% of charging, usually most iPhones will turn ON automatically and it STOP CHARGING! and my phone starts to GETS OVERHEAT on d motherboard side! It seems that my iPhone ONLY CHARGING IN TURNED OFF MODE! After d 4% drained completely, it will charges until 5% & stops charging again when d phone turns ON automatically!

Then i tried to replace using another battery dat have some amount of charges, my phone turns ON and functioning NORMALLY. But IT WONT RECHARGES & SYNCS when i connect with the cables & it starts getting overheats again. But it charges if it turned OFF. I assumes dat it was not either d Dock Connector nor Battery was d problem.

So I suspects dat d Motherboard was damaged bcoz d Liquid Damage Indicator on d damaged Dock indicates dat water was entered d phone, & d motherboard gets overheat while tries to recharge.

But if d motherboard was damaged, how come my phone still fuctioning normally if using a charged battery? I tried to make a Call, 3G Surfing, Play Music etc & it all works fine!

After doing some researchs, now i suspects dat d Power Management Unit IC was damaged. It iz bcoz dat it gets overheats specially on d PMU IC part.

So i sent my phone to replace d PMUIC, & i still waiting & hopes dat it is d last resort to my phone problems...