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MacTechTrainer, Sr. Mac Support Specialist
Category: Mac
Satisfied Customers: 1700
Experience:  Apple Certified Desktop & Portables Technician, A+, Cross-Platform (Mac/PC) Tech - for over 14 Years
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i cant get my mac g4 tower to stay on it turns on and the apple

Customer Question

i cant get my mac g4 tower to stay on it turns on and the apple comes up on the screen but no spinning circle under it. then it just shuts off. any ideas?
Submitted: 7 years ago.
Category: Mac
Expert:  MacTechTrainer replied 7 years ago.
Hello, and thank you for asking your question, with
I am Sr. Mac Tech Support Specialist, Terry, glad to assist you.


Here are some steps you can try to resolve the issue:
• First, hold in your power button for approximately 10 seconds to do a hard shutdown.

• Once your Mac is shutdown, you will need to perform what is called a PRAM reset (Parameter RAM)

• Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously .

• Turn on the computer.
• Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.

• Now, hold the keys down until the computer restarts and you hear the startup sound for the third time.

• Release the keys and allow the Mac G4 to start up.

• Please update me to let me know if this works.

If you have any more questions, regarding your technical issue, please feel free to reply to this post as I am always ready to assist. Thank you!


Customer: replied 7 years ago.
so now the computer stays on long enough for the spinning circle to come up under the apple but then the apple cinema display goes black. but the tower does stay on.
Expert:  MacTechTrainer replied 7 years ago.
That is a bit strange. But I will keep trying some options for you.

Here is a procedure I would like you to try:


The Power Manager is an integrated circuit (computer chip) that is usually on the logic board of your Mac computer.

It is responsible for power management of the computer. It controls back lighting, hard disk spin down, sleep and wake, some charging aspects,, and some input/output as it relates to the computer sleeping.

• If the computer is on, turn it off.
• Disconnect all the connections going into the Mac except for the Power cord.
• Once all connections have been disconnected, remove the power cord from the Mac.

• Wait 2 minutes.
• Reconnect the keyboard, mouse and power cord back into the computer.
• Press the Power button to restart the Mac computer.

I will be watching for your update.


Customer: replied 7 years ago.
nope still not better. now the computer isnt even staying on anymore
Expert:  MacTechTrainer replied 7 years ago.
That is an indication of the Power Supply possibly failing.

I knew if you were to have an unsuccessful PMU reset, this is not only a power issue, this appears to be more of an issue with the Power supply in your Power Mac G4 tower failing.

My recommendation, is that you consider taking your G4 tower in to your local Apple retail store or Apple service center, for a diagnostics at least. The main concern I have which is prompting me to make this recommendation, is due to diminishing functionality of the power of the G4, not to mention the Power Management Unit (PMU) is not making any difference in the performance operation of your Power Mac G4.

Just for your reference, I have taken the liberty to provide the store locater links to your local Apple Retail store as well as a general store locater for locating any local Apple Authorized Service center in your area.

Apple Retail Store (Genius bar)

Apple Authorized Service Provider

If you have any more questions, regarding your technical issue or what I have provided, please feel free to reply to this post as I am always ready to assist.

Thank you.

Sincerest Regards,

Customer: replied 7 years ago.
Ok so I got it to come on and stay on and it says " Falt catch!, code = 300 at ssro: 05610664 srr1: 00003030

then has all the mac info and then says welcome to open firmware, the system date is:

what should I do from here?