Super Nintendo (SNES) power supply repair


In this post I will show how to repair the Super Nintendo (SNES) power supply. I am working with a psu for a PAL SNES unit. This psu also fits the PAL Nintendo Entertainment System (NES). If your SNES is not powering on properly, you will want to check if your psu is functional. To do so, use a multimeter set to measure “AC”, and use it on the power plug of the psu, as shown below. As seen, my psu gave 2.24 voltage, where it should have shown at least 9v.

You need this 8 mm spanner bit to disassembly the PSU:

SNES psu low voltage

To disassembly the SNES power supply, you need a 8 mm spanner bit, as shown below.

SNES psu spanner bit
SNES psu disassembly
Note the 8 mm spanner bit to the right in the image.

Now, use the multimeter again: this time, measure between the two points where the power cable is attached to the transformer unit. If you get a reading of around 9V or above here, the problem is the cable, or the power plug. This is a good thing, since these parts are replaceable. I got a reading of above 9V, and could proceed to replace the cable and plug. To do so, I used the following material:

  • A new power cord with two cables.
  • A new power plug (2.1 x 5.5 mm).
  • A strain relief for the cable.
  • Some shrink tubes (not necessary if you use a thinner cable than I did).

Cut the cord next to the transformer, attach the strain relief, add shrink tubes and solder on the new cord. Solder the new cord to the two points as shown below. Since it is an AC power supply, the polarity does not matter. Measure the AC voltage at the opposite end of the cable and make sure you get a good reading (9V+). Proceed with soldering on the new power plug to the cable, and you are done! I had to use some shrink tubes to cover the cord in this example, which is not optimal, but it works. If you use a thinner cord than I did, it will look more aesthetically pleasing.

SNES psu repair
Don’t forget to add shrink tubes to the cables.

Anyway, that is it! Have fun with your repaired PSU. This model also fits the PAL NES.

An easier way is to use a pre-made cable (5.5mm / 2.1mm) as shown in the image below. Then you don’t have to mess around with soldering the plug to the cable.

I recently bought 2x broken NES PSU:s and 2x broken SNES PSU:s. Then, four of the above cables came in handy when I did the cable replacement, as shown in the image below (A NES Power supply).

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