https://www.ifixit.com/Guide/iPhone+3G+Headphone+Jack+Replacement/580
iPhone 3G Headphone Jack Replacement - iFixit Repair Guide
No audio? Replace the headphone jack!
headphone jack replacementiphone 3gifixit repairguide
https://www.ifixit.com/Guide/iPad+3+Wi-Fi+Headphone+Jack+Board+Replacement/11608
iPad 3 Wi-Fi Headphone Jack Board Replacement - iFixit Repair Guide
Use this guide to replace the Headphone Jack Board.
ipad 3wi fiheadphone jackifixit repair