It would be safer and to purchase a new power supply,a repaired power supply might pose a fire hazzard.
AT Power Supply - still in use in older PCs.ATX Power Supply - commonly in use today.ATX-2 Power Supply - recently new standard.
Electricity hurts
No attempt should be made to repair the power supply. The power supply should be replaced with a power supply of equal or greater wattage.
No, but they are usually not worth the trouble.
It sounds like you have a power supply problem. The capacitors on the switched mode power supply have changed value or failed completely. Replace or repair the power supply section.
A computer's (PC's) power supply is a sealed unit and should be replaced as a whole - It is dangerous to try and repair the inside of that sealed unit (that is why it is sealed).
The older models of the Xbox 360 have a different power supply to the Xbox 360 S. You cannot get a power supply which will work on both consoles, therefore you will need to buy whatever power supply your console needs.
If you are supplying power in vehicle or base station (using a AM-7239/VAA) it is suggested that 24Volts & 5Amps. The same type of power supply could be used in a repair shop.
There is no such thing as PCI power supply. Case power supply can supply power to your PCI-E ports by means of 4, 6 and 8 pin connectors. It's especially true for new cards where PCI-E power is required to operate. Anyway, there are couple ways to test pins. One of them is to buy computer power supply tester. Second is cheaper is you have multimeter... You can test each pair of pins, required voltage is standardized and can be found in internet.
It would be possible if you have the proper testing equipment and electrical tools to do the job.
If they have both failed at the same time it sounds like a power supply problem. Check fuses
The only fuse located in a computer is the one in the power supply. It can be very dangerous to open a power supply without proper training. If you do not have the requisite training to repair a power supply, please do not attempt to open it. Your life isn't worth losing over a $50 hunk of metal and wires.