What fuse does a apple power pc G4 power supply take?

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 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.

The power supply model number should be on a sticker on top of the supply when you remove it.

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

Hello, The power supply is part of the motherboard in the iMac G4, so it's hard to change it. The repair would certainly cost more than the price of your iMac. You can try to take off the small battery, and reboot it to see if it changes. To open the mac lay it down, screen on the table (on a t-shirt). Unscrew the four screws (they wont come out, so just unscrew them. Pull the screws and take off the silver plate. Then you'll have access to the inside. Good luck

Sorry man, I went through this with my Dual 2GHz G5...your logic board is dead, computer wont work till you replace it, and even that is no garantee your RAM/CPU's are in working condition, logic board failure tends to eat components like that.

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.