I have had the same problem but with constant jiggling and tapping the magsafe connector most of the time the charge light will eventually turn orange. I strongly suspect that many of the cases above are not so much an electrical problem as a mechanical one: the connector pins are just not making good contact with the connections. Try thoroughly cleaning both sides with rubbing alcohol and a q-tip and scraping of any buildup in the recessed socket on the mac. To me, it looks like the sockets on the mac side are looking a bit oxidized and worn, and I suspect I will eventually have to replace the connector on the mac side, as described here: [guide|38516]