atari 2600

Hiya, I am looking at picking up a power supply for my dads old Atari 2600 so we can get it up and working. I have found out that i need a 100V - 240V ~ 50Hz 9W input and a DC 9V 500mA output. I have found similar plugs with the correct input but the output is rated for 1A not 500mA (0.5A)...