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Rob, Mac Genius
Category: Mac
Satisfied Customers: 409
Experience:  14 years Mac experience, 10 years Mac Consulting, ran a printshop for 23 years.
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My PowerMac G4 will not complete boot process. I get gray screen

Customer Question

My PowerMac G4 will not complete boot process. I get gray screen with APPLE then blue screen with spinning clock that never stops.
Submitted: 7 years ago.
Category: Mac
Expert:  Rob replied 7 years ago.

Disconnect any items like printers, external hard drives, etc. from the computer. Try to start up now.

If that doesn't work, disconnect the power cord and try to reset the PMU on the LogicBoard by pressing the PMU reset switch (S1) once (and only once) then replace the cover and wait ten to fifteen seconds before connecting the power cord and trying to power the machine on.

If that doesn't work. Press the power button for 5+ seconds to power it down. If you have more than one stick of RAM, leave the computer power plug in, touch a metal part inside the case to discharge any static on you. Open the case of the computer and remove all but one stick of RAM. Here is a site that gives detailed instructions on installing RAM if you'd like that:

If it still won't power up, it may be the PRAM battery on the logic board. You will have to remove it, buy one at a Radio Shack or somewhere on the internet like Other World Computing. Here's OWC's website's PRAM battery page:
Rob and other Mac Specialists are ready to help you
Customer: replied 7 years ago.
Looks like I may have to replace the battery. Everything else fails to work. I wanted to add that this all started after I did, or attempted to do a Apple software update. I restarted after the attempt to do an update failed with the plan of trying the update again. I've never been able to get he computer to finsih booting since.
Expert:  Rob replied 7 years ago.
Most likely that is a coincidence. Even if something went wrong with the update, trying to start up with the System CD should start up. Hopefully the battery brings it back to life! Thanks for the accept.
Customer: replied 7 years ago.
After spending $13 to get a new battery the Mac will still not complete it's boot sequence. The Boot DVD just keeps being ejected. and no other boot modifier sequence works other than the Open Firmware. Any other ideas short of filling the case with cement and turning it in to a boat anchor?
Expert:  Rob replied 7 years ago.
I'm sure you feel like doing that. It's a pain when something won't work.

Since you installed the battery, try resetting the PRAM by starting up and as soon as you hear the startup chime hold these keys until you hear 3 chimes:

Option Command P R

After that, if you don't mind spending more money on reviving it, take it to an authorized Apple Reseller like an Apple Store.
Customer: replied 7 years ago.
Thanks anyway. Zapping the PRAM did nothing to remedy the situation. Boat anchor time.
Expert:  Rob replied 7 years ago.
Did you ever try starting up from the system restore CD? If you can do that, you could try reinstalling the operating system. If you are running a version of Mac OS 10 you could do a archive and install and not lose all of your information. Here's Apple's website on doing that: