8203435-b

[arash]

Apple startup tone, black screen even with external monitor. where to start ?

 

[dukefawks]

Start by turning on your brain.....
History? SMC_LID? Check with flash light for image? Voltage on L8304? Those are all things that should have been done already.

 

[arash]

It`s a MacBook Air and we have no history for it.

 

[smiba]

Start by turning on your brain.....
SMC_LID? Check with flash light for image? Voltage on L8304?

So how about these? Did you check? Please post results

We can't help you if we get no information we can work with