MBP not charging suddenly

Question

2007 Aluminium body MBP, 2.16 GHz core duo, 2GB RAM
Suddenly out of nowhere my MBP has stopped charging.  Battery is less than a year old, Magsafe works fine on another Macbook.  All has been working fine today.  I was using my MBP on the train home, putting it to sleep a few times while I switched trains and walked home.  Then I got home, and it had shut itself down despite having battery power left.  Started it up fine.
Now I tried plug the Magsafe in to charge it and the light on the Magsafe went green for about 1 second then off.  First thought was, it's a battery problem, but it's not working even with the battery out.  Then I thought, it's a Magsafe problem, but the Magsafe works in another computer fine.  I cleaned out my Magsafe connection so it's not that.
Tried SMC reset several times.  No change.
Any ideas what it could be?  Logic board?

Answer 1

I have spent the last week or so trying to get my MBP running again, and I have succeeded, but only for the short term.
I tried replacing the battery, this didn't work at all, the MBP didn't even boot up from a new, charged battery.
A brief bit of research led me to understand it would be either the magsafe left I/O board, the power cable that connects to the logic board, or the logic board itself, and that I should investigate in that order.
So, I got a left I/O board and replaced it using this guide:  https://www.ifixit.com/Guide/MacBook+Pro+15-Inch+Core+Duo+Model+A1150+Left+I-O+B oard+Replacement/504
When I put the Magsafe in, the light came on but after about 4 seconds I heard fizzing and a burning smell and then a tiny puff of smoke.  Upon examination the replacement I/O board had blown a circuit right above the headphone jack.  I decided that this was a duff I/O board and just bad luck.  Though, in reality, I have no idea whether this was a consequence of a different or bigger issue, and no idea whether this incident led to any damage on the logic board.
I got another left I/O board and repeated the process.  This time, same thing, except that the fizzing and burning seemed to be definitely located around the logic board.  The power was not left in for very long, but my heart was sinking all the same.  I took the logic board out using this guide: https://www.ifixit.com/Guide/MacBook+Pro+15-Inch+Core+Duo+Model+A1150+Logic+Boar d+Replacement/498  and took a look at it.  I noticed that there was one spot which looked like charring but not certain.
My next step was to replace the multicoloured power/battery cable that connects the I/O and logic board.  I did this, but I don't think it made a difference as again I had some fizzing, but then it stopped, and the Magsafe stayed on, and the battery started charging.  However, I was keen to rexamine the logic board so I took it out and noticed that the charring looked worse.  I took to see how bad it was by trying to wipe it off, and as I did that one of the components with the charring just dropped off.  I don't know what the component is, so have included a picture here so that somebody might help me ID it:
http://postimg.org/image/5g3gxf3el/
I have a tiny bit of hope that because there are three of these components in a row, that if one goes down the other two might take the load... probably doesn't work like that!
Once this component came off, I cleared up the charring and put the logic board back in and connected it to the power board.  At this point I ran power through the machine to see how the logic board behaved.  No obvious burning, BUT it got very hot very quickly.  My question at this point is, did it get hot because I didn't have it plugged up to everything?  If that makes sense?
Anyway.  I put everything back in place mostly because I had reached the end of what I could do with it, I think.  I put the Magsafe in place and the machine booted up automatically.  All good.  I shut it down and let the battery charge for ten minutes.  Again, I noticed that the logic board was getting warm, even when powered down, and not just because it was charging, but not as hot as it got the first time.
With the keyboard back in place and the casing screwed back together, I can now run my MBP seemingly as normal.  I cannot tell whether it is any hotter than usual but I am running my fans at high RPM to be sure, and registering a temperature of around 50 degrees C.  I also am going to go back in and reapply some new thermal paste to the heatsinks when it arrives.
So, long story short, my MBP is running again, but with a new I/O board, new power/battery cable, and without a tiny component (to be ID'd) from the logic board and probably at a high temperature.   I have backed up and now just keeping an eye on it, waiting for an inevitable failure!
(I took my MBP and story to the genius bar this morning and as expected, the guy just informed me that my logic board sounds like it's dead or dying and I should invest in a new Mac...)
Next thing, my battery is saying Replace Soon, which I am not thrilled about given it's 14 months old.  Here's the read out.  Does this make sense?
Battery Information:
  Model Information:
  Manufacturer:    SMP
  Device name:    ASMB012
  Pack Lot Code:    0002
  PCB Lot Code:    0000
  Firmware Version:    0110
  Hardware Revision:    0500
  Cell Revision:    0200
  Charge Information:
  Charge remaining (mAh):    3952
  Fully charged:    No
  Charging:    Yes
  Full charge capacity (mAh):    3988
  Health Information:
  Cycle count:    388
  Condition:    Replace Soon
  Battery Installed:    Yes
  Amperage (mA):    358
  Voltage (mV):    12592
Thanks for any help and advice.