Backlight is unreliable, behaves intermittently
Hello! I have a laptop, serial F8V, that has an intermittent backlight -- sometimes it's not on when the laptop powers on, and sometimes it is. Sometimes the backlight doesn't come back when the laptop awakens from sleep. You can always generally get it back on, but it takes powering on/off, etc.
The board previously had some corrosion that was cleaned off, and previously was not powering on fully, and just showing a glowing sleep light. So that issue seems to be resolved, but now I've got this backlight problem.
The question is this: Would this problem more typically be the board itself, the topcase/keyboar
The most common problem I've had with these machines is the hard drive/ IR sleep sensor cables going bad. They create all sorts of maladies including sleep and back light issues. They will also destroy hard drives. So try replacing the cable and use a hard drive from a known good machine (any 10.7 + system works for me. If nothing else it's a cheap repair attempt and the first thing I do on these machines. (so keep extra 13" & 15" cables on hand).
Have you tried resetting PRAM ? (Booting with Cmd+option+P+R keys)
Next step you can do is trying to reset SMC. (This progress is hard to explain so I refer you to apple's website for that Resetting SMC)
Next up is finding the connectors on the logic board which lead to the backlight. If you see any corrosion/solde