A1278 MacBook Pro - Shuts off when unplugged, or have to hold down power button ..

This isn't the typical issue of the battery being dead.

Situations:

Power Plugged In PRE bootup:

MacBook turns on as you would expect it. The moment you pull the plug, it shuts off. Sleep mode works fine.

Not Plugged In PRE bootup:

When the power is unplugged, I need to hold the power button down for about 5 or 6 seconds, if I release it, it completely shuts off. If I hold it until the grey screen, it runs as normal. If I plug it in at this point, it works fine and I can plug / unplug it and it wont shut off. If the Mac then goes into "Sleep Mode" - it complete shuts off.

If I press the power button, I get the reset/sleep/shutdown message - if I select sleep, the Mac looks to go into sleep mode, but then it seems as though it completely shuts down as I need to restart it from scratch.



I've tried the SMC a PRAM reset without change.

I called a local Mac repair shop, and he said he knows exactly what the issue is, and would be around $250 to fix it. Obviously he wouldn't tell me, thats his business.

Any help would be greatly appreciated!

Thanks!

Any thoughts would be appreciated!