(05/12/16) Site Updates!

Read more ...

Contact Me!

Comments, Questions or Site Suggestions? Fill out your contact information and the Captcha below
How many eyes does a typical person have?

DIY: SNES Power Supply for AKAI S20


I'm assuming you found this article from my "Dope Machines You Didn't Know Existed Series" where I mentioned I had purchased a power supply for a Super Nintendo, that matched the specs of the original AKAI S20 power supply, except the polarity was reversed and the plug did not match


Well look up "Akai S20 power supply" and chances are every forum post that will show in the search results will be a cut and paste of people repeating the same thing: "The super nintendo power supply works". A couple do mention the center pin issue. But most done. And not one of them mentions that the plug is not correct either.

I really reccomend you just get the Sega Game Gear power supply, as this might be too much for some. Easy for others.

So rather then just being able to reverse the polarity, we have to ditch the old wire/plug completely. 


This article is good for any situation where you have the correct voltage, but need a new plug size.


Now where we left off in the AKAI S20 article the NOTE read as:



The Super Nintendo power supply does not actually fit. The plug is way too big. All the forum posts you read saying this, ARE NOT TRUE.


The AKAI S20 requires the following power supply: 10V DC, 800mA, Center Positive. 


The Super Nintendo power supply is 10V DC, 850mA, Center Negative (The +50mA will make NO difference)


The Super Nintendo power supply's plug end is too large to fit the jack on the AKAI S20 (This needs to be replaced completely)


The Sega Game Gear power supply is 10V DC, 800mA, Center Positive 




Things you will need:

1.) Security Bit 

2.) New screws to replace security screws (OPTIONAL)

3.) Soldering Iron

4.) Power Supply

5.) Doner Power Supply with correct plug size




Get your Super Nintendo power supply and verify that you have the correct voltage (10V DC 850mA). This is a good pratice to get into the habbit of.

snes s20

STEP 2: 

The SNES power supply uses a security bit to secure the unit closed. You will need a bit that looks like this. I wish I had a size, name or number of it to offer, but sadly I don't.


On the underside you will see the two screws here, that need to be removed:


They look like this when removed:


You just pull the two sides apart, and this is what you have inside. Be sure not to touch anything on the bottom of the green piece (PCB). You can hold the circuit board from the edges just fine. The reason I say this, the blue cylinder there, that is a capacitor. Those store energy. So if you just had your power supply plugged in to the wall, chances are, that sucker is holding a charge.

Its not a nice surprise being zapped by them. It can really hurt depending on the size. General rule of thumb. You don't want to become part of a circuit. If you touch positive and negative of anything at the same time, well, you get current traveled through you.

You can pick it up from the big silver block! This is the transformer. The thing you do NOT want to do, is do not touch the pins, on the bottom of it. If this is still holding a charge some how, it could really hurt you. But anywhere on the shell should be fine.

Make sure if your equipment was plugged in recently, read online how to discharge it safely, and other precautions to take if your unsure about this process.

But you should also not let this scare you away. The only thing that will kill you, is if it is still plugged into the wall socket.


You can grab it by the sides of the transformer there, take it out, flip it over so the under side of the circuit board is down, and wires are facing up toward you. And this is all it is.


The board here is clearly marked + and - so you will know where to attach your wires


Get your doner power supply. Now double check again that your plug is infact the correct size for a good fit. There should be no force required. Open your doner supply, in a similar fashion as to how you opened the SNES power supply.

doner pwr box

Notice on the rear label, the polarity. From what it says, the center pin is POSITIVE. You want to make a note of this so you can match them. The center pin on the SNES has to be positive. So if your doners center pin is NEGITIVE, you want that wire to go on the POSITIVE of the SNES power supplys PCB. You want to always look at the diagram there, because you cant see where the two wires connect inside the plug.

Use this to cross check your power supply to know your polarity:



Now you want to crack open your doner power supply.

If there are no screws, such as in my case, as I used an old power supply for a router. You can set the box on the floor, and with a hammer, you can give a firm smack into the side where you can see the line where the two sides are joined. You do not need to hit it hard enough to smash it open. You simply want to split it, so you can pull it apart by hand.

Keep in mind if you hit a chuck of plastic like a transformer, while it's on a hard surface, it could fly up and hit you if you hit it hard enough. Or it could go flying into something else. You are not trying to smash it open! So again, do not hit it that hard. It's not a pratice you want to get used to. Best to do everything correctly.

snes split doner

With the new power supply open, check the PCB for your + and - connections. Like how you did on the SNES power supply? The new board will be labeled too.

You are checking these because you need to know which wire going to the plug is + and which is -

On my power supply the board was labeled RTN and VO. RTN typically means return. So that was ground. I followed the RTN wire and noticed it had white writing on it. The VO wire, or positive wire, had a long white stripe. I then knew, my cord with the white stripe is my center pin.

snes doner polarity

I want my center pin to be positive on the SNES power supply. So on a peice of paper, I write down "White Stripe on Doner Cable is Center Pin" and "Wire with writing is negitive" (This is good so you don't get mixed up and just blow another fuse and have to try all over again)

So, close to the board you can either clip off the wires, or desolder them. The choice is up to you. When your done, you can toss it in the trash, or save it for later parts that might come in handy!


Now you should have your SNES power supply open, and your doner wire. You can see in the photo my wire differences, if that helps you visually understand better what I explained above

snes doner plug

Cut off the SNES power cable from the board. And set it aside for if you want it later on down the road

old snes plug

Now take your new cable, and you'll want to solder the correct wires to the + and - on the SNES power supply

snes doner plug

Solder the new cable in place, and it will look like this

snes doner wire attached

Now here is an option step when your going to put the case back on. 

The security screws. If you do not like the security screws, and would rather an easier access from any screw driver, all you need to do is find a screw with a similar size as the security screws.

Ideally your new screws will be slightly thicker, as this way they will create their own threads into the plastic pillers where the old screws were threaded.

snes screws

You just use your screw driver and slowly drive the new screws into place, and you get new threads!

snes screws case

Now back the screws out, drop your power supply internals back inside, and close it up. Then your done!

snes powersupply complete

It might not be that complicated, maybe it only seems like it, having this being written in so much detail. I write everything with the assumption the reader has no expeirence doing this sort of thing.

So it might be complicated for some. Like I said, the Sega Game Gear power supply is a much smarter idea if you can find one online or locally in your area.

Add comment

Security code