Is my motherboard fried? Or just the battery?

Factual Questions
1

It’s a 3-4 year old Powerbook G4 laptop that has been prone to some heat issues, so I wouldn’t be too surprised if the motherboard went out.

I’m not getting anything on my display. No LED light, no anything. Just a black screen. One time, when I booted up, I got the screen to come on, but it was a scrambled mix of black and white dots, almost like you get on unused analog TV stations. I also don’t get any signal when I connect an external display.

The system seems to be booting up just fine. I get the boot-up chime, and I can hit the “speaker louder” button and get audio feedback that the command went through, something that only happens when the OS has loaded.

I’m thinking my problem may be the motherboard battery. I really hope it is. The reason I think this is that I can connect my iPod to synchronize, but the time is always completely off. This tells me that the computer time is not keeping consistent time, one symptom of a dead motherboard battery.

So, which is it? Motherboard, or the battery?

2

It sounds like your OS is loading just fine. Perhaps your video card connector or a memory chip has worked loose.

A quick search on “Powerbook G4” no video turns up this:
Powerbook G4 has no video but beeps

3

Probably a bad cable, or cracked solder joints on the graphics chip.
Neither is a DIY repair, and probably not worth fixing - you can part the machine out on ebay for $200 and buy a MacBook that a zillion times faster.