24" iMac boots to black screen help

[nREMfan]

I have a fairly old iMac - I believe it's an '08. Anyway, it's am aluminum 24" that has run like a champ for years. Last Friday, it was turned on and after the chime, the iMac does nothing and isn't responsive. Just a black screen

I've tried to zap the PRAM, check the brightness, boot from a Snow Leopard install disc ... nothing. You can turn it on/off via the switch on the back, but that's it. Attempting to zap the PRAM, or anything via the keyboard does nothing. So all we get is the chime, and then it just "stops".

Is this a dead motherboard issue? Or does anyone have any suggestions on what to try?

Thanks in advance.

 

[Dadioh]

I have a fairly old iMac - I believe it's an '08. Anyway, it's am aluminum 24" that has run like a champ for years. Last Friday, it was turned on and after the chime, the iMac does nothing and isn't responsive. Just a black screen

I've tried to zap the PRAM, check the brightness, boot from a Snow Leopard install disc ... nothing. You can turn it on/off via the switch on the back, but that's it. Attempting to zap the PRAM, or anything via the keyboard does nothing. So all we get is the chime, and then it just "stops".

Is this a dead motherboard issue? Or does anyone have any suggestions on what to try?

Thanks in advance.

Try this. Shine a flashlight on the middle of the screen and after the chime, see if you can see the faint apple logo as it boots. If you can see it then it is a problem with the backlight not working.

If you can't see a display at all then it might be the panel or the graphics card.

edit: You can rule out the graphics card if you attach a second monitor to the mini display port. If you get an image there then the graphics card is probably OK.

Good luck.