Strange charging issue

I've been having trouble with my macbook not charging. I sent it to the shop I bought it from to have it worked on and he called me back in 30 minutes to tell me it was fixed. He sent me pictures of the orange light and lightning bolt symbol to prove it. He sent it back to me Fedex and, at first, it didn't work...then the light turned orange and it began charging. The light soon dimmed but still charged. A few hours later it wouldn't charge again, (dim light and 'not charging' next to battery icon). So it went from working, to working most of the time, to not working at all again in the course of a day. As far as I know, the tech reset the SMC (which I have done) and replaced the DC in board. Does this sound like the logic board? This is really frustrating, and from what I've seen on these forums, not uncommon. On the positive side, the computer still works, but it completely defeats the purpose of having a portable. My battery is good, so is the magsafe. I've also tried all of the battery updates from the Apple website. This computer is not under warranty and not eligible for Applecare. There are plenty of threads about macbooks not charging but I haven't come across one which started working again for a brief time.

Thanks (sorry for the long post)