PowerMac G5 Wont Power On No Lights

Is it a 2.5 or 2.7 Ghz PowerMac G5? Sadly those machines were based on liquid cooling, and if that goes, they go unless you repair the unit that cools it. Another thing to consider, is replacing the PRAM battery. Typically no more than about $10-$15 at Radio Shack.

I am having the same problem with my G5 June 2004. Have you found a solution yet?

Also, I have tried to boot from 10.4,10.5,the apple ASD 2.5.8 dvd. Just the black screen, fans run and rev up then back to normal rev. The only way I can power down is to unplug it from the wall, power button wont do it, the led light goes on when I press it. Any insight would be appreciated. Thank you.

Did you follow the PMU (Power Management Unit) reset procedure exactly as specified by Apple?

http://support.apple.com/kb/HT1939

Another thing to try is some software diagnostics. If you have the original system disk, you can run the Apple Hardware Test from that. Of course there are commercial tools (like TechTool Pro), but if you don't want to spend money, you're stuck with whatever you can find on the web.

In any case, your software diagnostics should tell you whether you have a bad CPU. If that's the case, and your eBay seller won't make good on it, I'm sorry to say that your options are limited. If you have the tech skills to replace the CPU assembly, that's one option, but that might well exceed the cost of just buying another used machine...this time from a vendor who'll stand behind what he sells.

Some eBay vendors offer a third-party warranty on what they sell, the price of which varies depending on the selling price of the item. You usually have 30 days from the time of sale to buy the warranty. When buying a machine on eBay, I would only buy from a seller who offers that feature. In that way, if the machine is dead on arrival, you still have time to buy the warranty, and it will cover the purchase. The warranty covers the cost of shipping the machine to the repair center, and return shipping of the repaired machine. If they can't fix it, they refund your purchase price.

Also, eBay Buyer Protection should cover your purchase, without any extra fee. If the seller won't make good, you have to contact eBay to help resolve the issue. See eBay Buyer Protection for details.

Did you follow the PMU (Power Management Unit) reset procedure exactly as specified by Apple?

http://support.apple.com/kb/HT1939

Yes I did, I reset both 2.0 cpu's and the video card, all the ram, then took the ram out and tried it two at a time.

I also checked the trickle voltage and got 5 volts, it was not under load, I am not sure how to check it that way.

I have not noticed a led light on the logic board. I read somewhere there should be a yellow led light on for the 5 v

trickle, I don't know if it should be on or off if it is good. There is a red led that goes on when I remove the plastic door, and then off when I put it back on.

Thank you freevito for your time!