The lights are on but no body is home...

Hi there,

My friend asked me to have a look at his macbook as it wasn’t booting. It a 2008 macbook but so i suggested a new one but he said if it can be fixed he’ll just not have a laptop so I’m really keen to fix it.

When plugged in the laptop charges normally (orange light then green when charged). When I turn it on the light at the front comes on and the drive spins up but nothing comes on the screen. 2 seconds later the power cuts off (I can hear the HDD drop the needle). The it’ll turn back on, (with the light and drives) but still won’t boot. There’s no chime and no beeping from the Motherboard.

I’ve tried resetting the SCM which went fine (orange to green then back to orange) but still no change. I thought it might be a dead logic board but would I even be able to reset the SCM if that was the case?

I’ve also tried:

Booting with no RAM and with different ram sticks or just one stick in either slot.

Booting with the track pad disconnected

Booting with shift down to get into safe mode

Booting with Cmd R for recovery

Booting with Cmd Opt P R to reset PRAM

Booting with no battery and draining the power totally

Booting with a second screen connected (also shined a light through the apple logo to check for a backlight issue but it’s totally blank)

All of the above did the exact same (powers on then off then back on but no screen)

I tried his HDD in my mac and it booted fine so it’s not an issue with his HDD.

I also fully dismantled the laptop and checked over the board with a magnifying glass and couldn’t see any obvious damage.

I’m pretty tech savy and think I could replace a BIOS chip or the whole logic board but don’t want to spend the money if it won’t help. I tried a lot of different google searches but couldn’t find anything similar anywhere.

Anyone ever heard of this type of fault and have an idea what it might be? Any help or pointers would be appreciated .

Thanks

Xav