Screen not working on macbook, help please!

I've got a late 2006 macbook and the screen stopped working and i'm looking for some help.

Symptoms - screen works intermittently, it stopped working for a couple of months (I had it running through an external monitor) then randomly started working again. It ran fine for about a month then stopped again. When the mac is switched on it goes grey as it normally does around the time of the startup sound then goes black again after a few seconds. It always runs fine with external monitor. The screen is completely black - nothing there if you shine a torch on it.

I took it to apple when it first stopped working and they said it was the inverter - so they changed this then called to say they changed the inverter but it still didn't work so it was the display that was faulty and needed changing. They wanted a lot to change the screen so i didn't get them to do it. I just bought a new screen (genuine one) and fitted it today. When first switched on, the screen was on at startup for a bit longer than normal but then black again. When plugging the external monitor in the screen worked again briefly but then went off again.

I really am stuck as to what this could be. I have reset PRAM, tried battery out and holding down power etc. Just in case this could possibly have any bearing on it, my battery is broken so just runs on power supply all the time.

Any suggestions of what it could be/what to try would be great.

It sounds like a loose or possibly a bad video cable from the logic board to the display. Since the inverter was swapped out and the display (which incorporates the backlight) the only thing left that makes sense is the video cable. Go to iFixit: The free repair manual and take a look at the repair procedure. You may also be able to buy the cable from them.

Thanks for that, i'll give it a go and let you know how i get on.

Hi chscag, was just wondering, why would the screen come on grey (working fine for a few seconds) everytime you switch on if it was a faulty cable/connection? I'm just trying my best not to have to take the machine apart again if there is any way of avoiding it! That ifixit guide is really good, i changed the screen with a youtube video and wish i'd seen those guides before! Might not have had three screws left over once i'd put it back together!

Just on ifixit i noticed something about PRAM battery causing loss of video when they go dead, could this be anything to do with it?

Yes, that's a possibility and actually easier to swap out the PRAM battery before proceeding with changing the cable. Your question about the screen coming on grey and then going off can be caused by a bad cable. But change the PRAM battery first.