Chosen Solution
I have a mid-2012 Macbook Pro (A1278). Laptop was working fine two weeks ago. I recently tried to turn it on and there is no life in it. When I connect the magsafe charger the light is very dim and flickers orange. There is also a faint repetitive click coming from the jack. I initially tried to reset the SMC and PRAM with no effect. I have tried a replacement charger and battery and magsafe jack board, also with no luck. Any suggestions would be very appreciated as I’m trying to avoid spending £250+ on a new logic board.
A dim MagSafe Adapter LED implies the charging circuit on the logic board is having problems. Did you get your system wet at some point? Something spilled into the keyboard/trackpad? Often the liquids short out the MOSFET’s or corrode things up. Did you see any damage when you took the logic board out? And lastly did you use proper ESD practices! In the winter the air gets very dry so static (Zap) can create issues like this.
