How to find model of power supply for G4 power PC?

Processors are liquid cooled on G4s check and see if there is fluid in the bottom of case . if there is go see ur Apple dealer, They replaced mine.

You need a expert. Thank you.

You could try www.applemacparts.com think they might be uk based bit you should be able to isolate what the part number is. Hope this helps.

Your machine is a "Gigabit Ethernet" model PowerMac G4.
The power supply for this model is 661-2332 or equivalent. It has a 22-pin connector.

I'm not sure exactly what you mean by "is not swich on" but I'm assuming your G4 will not turn on when you press the power button. You most likely have a bad power supply. If you want to make sure it is the power supply and are comfortable using a multimeter and following a few instructions then I've included a link below to an Apple knowledge base document explaining how to test a power supply.

How to test the power supply

WARNING: You will be working with live power. Take caution to follow the directions exactly and pay attention to where your placing your leads.

Hope this helps, don't forget to leave feedback if you found this helpful.

IT IS THE POWER SUPPLY MOST LIKLY CALL AROUND FOR A NEW ONE OR HAVE IT FIXED IS ALL YOU CAN DO MANY PLACES DO POWER SUPPLYS

Hi,
Get in touch with the Apple support team in case your machine is under the warranty time period as they would offer service free of cost:
http://www.apple.com/support/contact/

mite be if cd is duplicate it wont work and make sure ur lens is proper

The most common problem with imac G4/800's are failing logic-boards. This will cause the mac to not power up at all giving the impression that the PSU is broken. 
If however, you are indeed certain that the fault is with the power supply, they are available from many stores online
Power Supply for iMac G4 15" LCD (700 & 800 Mhz) 661-3184 614-0147

Is this a tower or Imac?
Is there a reason other then curiosity you need to know?

All power supplies have it labeled on them what they are if you need it.