Imac G4 17" Flat Panel Screen Black

L

LayDyDay

Registered
Hi there,

I've had my iMac G4 17" Cinema Display desktop for about 3.5 years. I don't use it much anymore, but do leave it on basically all the time. Today I lent it to a friend who has been having computer troubles and is thinking about buying a Mac. It was working fine when I shut it down and packet it away. However, now that it's in her apartment, it won't work at all. When you go to turn it on, it makes some noise like it's starting and the base gets warm/hums (so we know it's plugged in properly) but the light on the display doesn't flash and the screen stays black. I don't think the problem is with the backlight, because in that case the little light on the front of the computer would still come on. It's like the monitor is "unplugged" from the base somehow, but I don't know how that would be possible since they're ATTACHED. We didn't drop it while moving it or anything... Any help would be greatly appreciated.

Yours,

Ava

P.S. This computer is no longer under warrenty and I don't have Apple Care. There is an Apple Store near me though...
 
You might have to change the small Lithium battery in the body. If it looses its power, it messes up the settings which can effect the sleep modus for the screen. They last only for about 3 years anyway...
 
It's unlikely that replacing the battery will help. That will require opening the bottom case to get access to the logic board, and you MUST redo the heat sink compound to prevent overheating of the processor.
Before doing that, try something more simple - Reset your parameter RAM, by holding the Option-Apple-P-R keys during a restart. You will hear the boot chime. Continue to hold those same 4 keys until you hear the chime 2 more times, then release the keys and let the system boot normally. If you now see video, you are OK. If not, shine a bright light directly into the screen, or move the screen to change the lighting reflected on the screen. You want to look carefully to see if any video is showing on the screen. It will be quite hard to see, so look from several different angles, and change the lighting in the room. Check to see if you can see anything, no matter how dim. If anything is visible, then your backlighting has failed, and the display will need to be replaced (probably). If you see nothing on the screen, and it remains completely black, then the 'inverter board' probably has failed. Either way, take to an Apple service to get checked. They can connect to an external display to discover if the logic board video chip has failed, which will mean replacing the logic board.
As you can see, there are several possibilities, but I hope a simple PRAM reset has got you going again...
 
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