I've got a TiBook (DVI) 867Mhz.

I also has freezing issues, ressetting the PMU sometimes helps, sometimes it doesn't. I never had any issues with it and i guess its a motherboard failure. Replacing the motherboard seems pretty easy, I have opened it several times and the machine is pretty open for changes. However, those motherboards seem rare and expensive to find.

I'd love to get mine running again, i love the feel of that titanium

Did you find any solutions yet?