I skimmed through the thread hoping for some links to documentation, thanks for the schematic, should help me mod my macbook, here are my quick comments:
I noticed a few suggestions for an 'Electrical Engineering' degree. Although probably many EE's possess the expertise necessary for circuit level debugging/repair this is not the purpose of the degree, hence not what the courses are focusing on. If you want to take the school route maybe something like 'Electronics Technician' at a local college?
That being said... one of the best ways to learn how to debug hardware is to learn how to design it, haha!
Just playing around with electronics and becoming familiar with the basic lab tools will jump start you in the right direction. You can make a cheap lab power supply out of an old PC power supply, and rig up an oscilloscope with some voltage dividers and an old soundcard or other scrapped data acquisition card, or maybe even arduino?. There are also some 'decent' usb scopes but be carefull there's lots of junk. You will be operating in a limited frequency range but should get you going.
Hands on, tinker, tinker and things will start making sense. There are tons of 'kits' and instructions online, get building! You will realize that none of your creations work on the first try, and THIS is where you learn how to debug! There are so many resources online, this is a great time to get into electronics!
Cheers and good luck!
Kuba
P.S. Check the EEvblog: http://www.eevblog.com/