Chosen Solution
my macbook air mid 2010 won’t light up the only light that goes on and off is the caps lock key. i can plug in to another screen using the dvi out port but thats it nothing on my macbook. i have tried all the resets pram safe boot etc nothing works. please help as I’m on a budget and don’t want to put it in the bin. thank you.
So just to clarify, the external display DOES work and display the proper video? If so then your GPU is likely ok. Assuming this these are the steps I would take:
Shine a light into the display while the Mac is powered on. If you can see images/video then your backlight is out. Try adjusting the display brightness using the F1 & F2 keys. If adjusting the backlight brightness has no effect then try a PRAM/NVRAM reset, holding Command+Option+P+R while powering on your Mac, releasing all of the keys after you hear it chime three times. If the issue persists then I would attempt an SMC reset, make sure your Mac is connected to it’s power adapter, hold Shift+Command+Option+Power button for about 5 seconds then release all of them together, wait a second then attempt to power on normally. If the issue still persists then you are dealing with a hardware issue. Possibilities include a blown backlight fuse, failed inverter or failed display.
If the above test did not show any video on the internal display then I would take the following steps. If adjusting the backlight brightness has no effect then try a PRAM/NVRAM reset, holding Command+Option+P+R while powering on your Mac, releasing all of the keys after you hear it chime three times. If the issue persists then I would attempt an SMC reset, make sure your Mac is connected to it’s power adapter, hold Shift+Command+Option+Power button for about 5 seconds then release all of them together, wait a second then attempt to power on normally. If there is still no video then I would check things at a hardware level. Removing the bottom case I would disconnect the battery then disconnect and reconnect the LVDS (video) connection at the logic board (Step 20). If the issue still persists then this is likely a hardware failure. Likely failed components would be the display assembly and/or logic board, although I would lean more towards the display.
Hope that helps!
You may find that if the computer does not start then the cap light may be signalling what is wrong. Sometimes on computers (Not sure about Apple) if the computer will not start the caps light sometimes flashes in a unique pattern to indicate the issue. Look to see if it flashes in any sort or pattern.
