The DC power connection (plug) is a proprietry connector, that has lugs that prevent under powered power supplies being used with an incorrect XBox 360:
- A 203W power brick will work on all XBox 360 variants;
- A 175W power brick will only work with a 175W or 150W XBox 360;
- A 150W power brick will only connect to, and work with, a 150W XBox 360
DC power cables
- The DC power cable is permanently attached to the PSU and connects to the Xbox 360 console. The DC power cable may have two grey buttons that must be pressed to release the plug from the Xbox 360 console housing.
- The DC power cable is 1.1 metres (approximately 3 feet, 6 inches) long.
- A proprietary power connector is permanently attached to the end of the DC power cable. This proprietary power connector is designed specifically for the Xbox 360 console power socket.
Power connectors for the original Xbox 360 console:
1 – 203-watt connector
2- 175-watt connector
3 – 150-watt connector
The connector on the end of your PSU is keyed to fit into the Xbox 360 console with which the PSU is compatible. If the power cable will not plug into your Xbox 360 console, make sure that the PSU is the correct kind for your console.
See also Xbox 360 Power Supply Hack
Header image courtesy of Quick Power Question
As an aside, most, if not all, of the information in this thread, Xbox 360 Elite Power Supply Question, is incorrect. You can use a higher rated PSU – just because it can supply a higher number of Watts, it doesn’t mean that the device will sink those Watts. The PSU does not pump in a higher voltage, or current. Utterly ridiculous advice is given in that thread.