Hello.
I bought a used NES long time ago. But the seller screwed me up somewhat since she didnt include the PSU (and I didnt even look in the bag she gave me, though I got Bubble Bobble and Mario 3).
I have a 9v powersupply I loaned from my Super Magicom backup unit and it works well with the NES but I want to buy a new PSU for the NES. I dont know the polarity of the PSU since it has no markings so what polarity should the new PSU have?
I havent got a voltage checker so I cant check polarity myself.
I have found out that a 9v 300ma center polarity works on the NES. Its a bit weird that this information isnt easy to find. When I got my NES without PSU I searched for it on google and finally asked people around on IRC and forums, no-one had ha clue!
Anyway, gotta buy a cheap psu and sell the console!
Why sell it? You'll get hardly anything for it.
The PAL NES (and SNES) runs on a 9V AC power supply - it'll have a rectifier somewhere internally to turn that into DC, so it shouldn't matter what polarity you use for the main input.
Or you could get a exact replacement.
It's 9V around 800ma AC, go to Maplins (www.maplin.co.uk) and buy N58AT at �9.99 as a replacement.
Using a DC PSU sticks current through 2 diodes internally for too long and 300ma is far too low a current anyway, you'll end up frying the PSU...
Failing that you could remove the diodes and cap and fit some wires so it becomes a DC machine and can use a standard 9V 1Amp Negative polarity PSU (used on nearly everything... Megadrive, PC Engine, Neo Geo, Super Famicom, Famicom...)