Hi,
I have MAC g5 20" and its shutting down on me all the sudden. I have replaced the power supply. None of the logicboard capacitors are bloated and all indicator lights on the logicboard work 1, 2, and 3.(4 does not stay on)
What other areas should I look to solve the problem?
Thank you.

Possibly heat related?

As much as I liked the G5 series macs, the Imac G5's were always problematic when I worked at Apple. They were always coming in for issues related to them shutting down on their own, and never turning on again. Cramming that G5 cpu in such a tight space was not such a great idea.

Anyway, taking the motherboard out and giving it a good cleaning helps alot, the mixed use of copper and aluminum seems to cause alot of corrosion around the CPU, especially on the heatsink, it starts to grow green stuff after a year or so in service. Not good. I have one now I'm working on if you would like some pictures of this. The machine cuts off randomly and sometimes will not boot up at all and the light will glow bright. Other times it will boot and the start up sound is all crackly. Fun times.

Still prefer the G5's and PowerPC's in general to intel crap macs.

Core 2 Duo 1.86

Thank you so much for the detailed reply. I am new to Macs. I like it; however, getting parts is not that easy and there are the prices are so expensive.
With the Intel, at least you can buy it anywhere for a good price.
Do you have any vendor that you recommend?
Thanks again,

Well, I worked for apple so all replacements came in directly from them, or machines were sent off to various locations to have parts replaced.

As the PowerPC series of machine is no longer being manufactured, there are too few spare parts and availability drives the price.

If you are new to macs and do not own any legacy(PowerPC) software you wish to run, than purchasing an intel mac might be a good option for you. For the rest of us loyal mac users that have to deal with Steve Jobs running apple it is a big pain in the butt. The PowerPC series was far superior to anything intel has and it is a shame no true macintosh's are being made anymore, just PC clones that look better than a normal clone.

Anyway, eBay is by far the best option for old(er) parts. Tis how I keep my 9600 MachV running strong.

"Old mac milt" is a typical seller of old world and new world parts.

Core 2 Duo 1.86

Outlander..thank you for speaking truth here!
I'm so tired of trying to explain why the power pc was still (IMHO) superior..
Funnily enough..when apple made the switch..absolutely nowhere did they even imply that intel was superior, but rather that they liked Intel's 'roadmap' (read..happy shareholders for apple!)
They're definitely some of the nicest PC's out there,now, tho...
But Macs? hmmm

Intel as it stands now is better because PPC had reached the end of its road. You just have to look at the stats to notice that.

Can't wait till I get my MacBook. Intel Goodness!

I POAST THRAD!!!!!!!!111!1!1!!