How do I replace usb charging port(which is attached on speaker)?

crazy_anupam7, If port is found to be bad/loose/damaged , this is really not a repair for the inexperienced because the charge port for your device is soldered to a board and the heat generated could cause further damage if not very careful. I will post a link to a disassembly video to get you inside the speaker to check the charge port and will also post a link showing what is involved in repairing/micro soldering a mini USB attached to the board(not your speaker, just an example of what may be required) as your USB port does not even sit in the same position. 3rd link is Logitech support to see if part is available as a whole assy. perhaps. The last link is to a site that offers the service to repair, which you could also try a few good local cell/computer repair shops have them take a look and estimate repair. Good luck. I hope this helped you out, if so let me know by pressing the helpful button.

https://www.youtube.com/watch?v=HsG1vvy5...

https://www.youtube.com/watch?v=vovPQFEb...

http://www.ultimateears.com/en-us/uemega...

http://www.ebay.com/itm/LOGITECH-UE-BOOM...