The ill-fated Atari 5200 doesn’t use the same power supply as the more popular Atari 2600. If you need a replacement power supply, here are Atari 5200 power supply specs that will work.
There are any number of common power supplies from other consoles that will fit, but most of them will damage the console, so you have to be careful.
Atari shipped two different power supplies with the 5200, but either will work with either model. The Atari 5200 has some tolerance. An Atari 5200 power supply isn’t generally something you can expect to buy at just any game shop, but you can find what you need on Ebay.
A suitable replacement Atari 5200 power supply
You want a 9v DC, center positive, 2A AC adapter with a 2.1mm x 5.5mm plug. Be sure to read the description of whatever you buy or zoom in on the photo to ensure it’s center positive. Refer to the image on the left for the symbol to look for. Center negative will damage your console.
If you buy the wrong thing, you can use it with a Jaguar or Genesis. But I’d rather you buy the right thing the first time. It should cost around $10, sometimes less.
Scrounging an Atari 5200 power supply
Check your junk box, or the box of AC adapters at a local thrift store. If you find a power supply that’s 9 or 10 volts DC, positive polarity (also known as center positive), and at least 2 amps, you’re good. Trace a Nintendo NES or Sega Genesis plug onto a piece of paper to use to compare. The Atari 5200 uses the same size plug, just a different polarity.
Alternative use for an Atari 5200 power supply
The nice thing about this AC adapter is it can double as a Nintendo NES power supply. Just don’t do the reverse. An original Nintendo NES power supply will damage an Atari 5200.
I recommend writing the name of compatible consoles on your AC adapter so you don’t accidentally plug a 5200 supply into a Genesis or, worse yet, a Jaguar, and damage it.