iphone 4 speaker works only when cable's in..

[strings8]

Hello... Just bought Iphone 4 g from a friend's colleague two days ago, so at first when i connected iphone to pc, it would give an occasional, "iphone charging is not supported with this accessory" message but i unplugged cable and connect it again and it would start charging... so i took out the cable after downloading some stuff into iphone from pc and this time sound from the speaker is stopping again and again... it works for for few seconds and then stops and so on...
strange thing is that sounds from speaker works absolutely fine when data cable is connected to iphone so does it mean i have destroyed my dock connecter?? will it be changed?? seller of iphone has been using it for quite some time but he insists he never had this problem... what did i do in just two days to spoil it?? pardon me for writing so many words.. but m frustrated.. Thanks a lot for your help...

 

[jollyreaper]

Bad charger port on the bottom. What's happening is the thing thinks the phone is plugged into a player and is playing sound through the connection. Doesn't matter that never in my life do I use that feature, my phone does it to me, too. Intermittent problem. There's a rubbing alcohol and credit card trick to try to clean it out. I've had limited luck.

Plug in and remove headphones, reset handheld. Those steps can sometimes fix it. But it's ultimately a bad connector and will continue to get worse.

My phone has a bum charger port and the volume up button has died. Have to go into a music app to bump up my call volume.