How do I test my LED Driver Board(s)?

Hello everyone, my A1226 MacBook Pro is having a problem with the backlight not working. Otherwise everything seems to be functioning normally.

So far I've replaced the LCD screen, the display data cable, the LED Driver Board and the iSight cable (know this last one is most likely unrelated).

After replacing all of these things, the problem still remains.

I know that this points to the logic board being faulty as the most likely culprit.

Before I blame the Logic Board, I was wondering if anyone might be able to tell me how I can test my two LED Driver Boards to see if they are faulty.

I only ask this because I purchased my replacement LED Driver Board from ebay at a ridiculously cheap price - they said it was working properly, but I bought it for just $9 (sells on ifixit for $60). Hence my suspicion that my original LED Driver Board failed, and that the cheap replacement I bought might also be faulty.

Do any of you know a way that I can test my LED Driver Boards, armed with my multimeter and various other household items?

Otherwise, if you know of a way that I can test my logic board to be sure that it is causing the problem, I'd be very happy to hear it as well!

Bottom line, I'd like to know which component is causing the problem, and would like to figure this out using another method than trial and error.

Thanks!