not charging but battery is ok

Naresh, you said the battery is okay, but until you can check that it maintains a charge, I would replace that first, check your battery connector. Make sure it is in good working order. If that does not work, you could have a problem with the charging circuit. I'd start with the dock connector, then open the phone and check all the charging components. This could be caused by a failed/damaged charging coil. Check for any physical damage, or if you have the knowledge and tools, check for function. You want to start by checking 3 inductors. For that, of course, you need a multimeter, or at least an ohm meter, to check for continuity. I hate to refer to those as fuses, but they most certainly control part of the charging circuit. First one is reference designator L3, it is a FERR-120-OHM-1.5A inductor. L4, right below it , has the identical value. Next would be the charger inductor L28 2.2UH-1.8A-155MOHM. All of these are pretty much available at mouser. com or digikey.com. Check the Diode D604, located just above L28. to answer your question directly, yes you can change the IC if you have the equipment and skills to reball. Hope this helps, good luck.