Screen dead after possible sleep. AHT passed, outputs externally can't boot into OS

My Macbook screen is dead after leaving it turned on at 18% battery, when I came back to it, it wouldn't turn on but the battery was dead. No faults found on AHT, light sleep light comes on when I close the lid? Outputs to external monitor! I tried resetting the SMC by the standard connect to magsafe, command option shift, reseated the RAM, reset the SMC by removing the battery and holding the power for 5 seconds...
It came on briefly last night again after I'd reattached the hdd cable, but it wouldn't boot - just ran the status bar. Now I've repaired the hdd, which did find a few minor errors, but I had to do this in single user mode attached to en external screen, as booting to recovery off recovery partition or a boot disk makes the screen go blank after it passes the boot selection screen.

Please help me with any possible advice!!

Thanks in advance,

Laura

gbr80 said:

My Macbook screen is dead after leaving it turned on at 18% battery, when I came back to it, it wouldn't turn on but the battery was dead.

Click to expand...

Can you give us more info/history as to the condition of the battery?

- Has the battery been fine up to now?
- Will the battery charge?
- etc.

What ever you can tell us may help.

- Nick

The battery's been fine up to now, unfortunately I can't tell you cycle counts as I can't get into the utilities.
The AHT extended testing also showed no trouble.

It will currently charge no problem, and the charger is fine.

I've just swapped out the HDD for a different one with a working OS on it from a similar model - the screen backlight now comes on, but now with no chime...

Update: that was a one time thing - the backlight doesn't come on now with the other HDD..

Ok, so final update for now - the screen comes on fir the initial apple logo, then flicks off. With both HDD's I can then switch to a thunderbolt external display, on my spare HDD when I then remove the thunderbolt connection, the display comes back on the MacBook, but on my normal HDD, it doesn't seem to want to do that and stays black. This is really weird - could it just be the inverter? Or does it sound more like something else? I'm stumped!!

Thanks all for reading,

Laura

If you are attaching a Thunderbolt Display, exactly what model of MacBook do you have?

It's a MacBook Pro 13" Mid 2012 with 640GB HDD and 8GB RAM. I'm only attaching the thunderbolt as I can't get the screen to display each time on boot...

Thanks,

Laura