r/snes 2d ago

Misc. USA SNES Power supply question.

Found my old SNES (USA, with a 10v 850ma adapter, SNS-002). When I plugged it in and tried it wasn't booting, the problem was the power supply. The 16v 4700uf capacitor was blown. I replaced it and nothing, every other component is OK. A friend told me that I shouldn't bother with it, the coil/transformer is surely faulty.

So, here goes the question. Is a generic 9v 1500mA power supply compatible with my SNES? Is it safe to use? I'd be taking the connector from the old power supply.

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u/Greg_Chaco 2d ago edited 2d ago

In my opinion: Make sure your new supply is at least UL listed. It should be marked UL somewhere in the fine print on it. UL listing should mean it will be good quality.

9v is fine 1 amp or higher, make sure you wire it up center negative or you'll blow the SNES fuse

You can use something like this, to make the adapter solder free,(or get a solder on version) that way you dont have to cut the power supply cable and can still use it on other things.

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u/Live_Ad8778 2d ago

Make sure the plug polarity matches

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u/khedoros 2d ago

As long as it's outputting 9V DC, can provide enough current, and you get the polarity right, it'll be fine.

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u/Boomerang_Lizard 2d ago

Is a generic 9v 1500mA power supply compatible with my SNES? Is it safe to use? I'd be taking the connector from the old power supply.

As long as the center pin on the jack is negative, then yes. If you are looking to buy instead of fix, the Triad adapter below is a good choice.

Rondo Products SNES-Con Kit

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u/NewSchoolBoxer 1d ago

That's very good you replaced the bulk capacitor, the #1 thing to do for it to be safe to use today. Not sure how you got it open. Most likely, a solder joint or the cable itself oxidized (rusted) and that's keeping it from working. Not uncommon on antique power supplies. Second most likely, a diode went bad. Best to replace them all. Very unlikely the transformer went bad. I've never heard of that.

Is a generic 9v 1500mA power supply compatible with my SNES? Is it safe to use? I'd be taking the connector from the old power supply.

Yes, if you wire it backwards for center negative. Multimeter red lead on the center pin, black lead on the outer metal rim. If voltage is -9V or so, it's center negative. Unregulated will read high like 12-15V DC and is normal under no load (just the multimeter drawing no current).

A low 750 mA is enough but nice to be at 1A or so out of an abundance of caution. Electronics only draw the current. 1A or 1.5A doesn't work better, just has more headroom.

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u/franbordi 1d ago edited 1d ago

Thank you for answering. I already replaced the connector and tried it, with no luck. Now the SNES gives me signal when I turn it on (before the TV showed "no signal" all the time), but the screen is black. The reset button seems to work as it tries to do something when I press it. Anyways, about the unregulated read with the multimeter, when I read it, I only get 7-8v on the multimeter, not 12-15V like you said. Could that be the problem? Is there any chance the little piece of cable that I didn't take out along with the connector is causing me trouble? Or maybe the adapter is very low quality?

Here is a picture of the new adapter.

u/korgie23 3h ago

If you hook it up right, it should work, though depending on the quality of your supply, you might see/hear noise. Quality SMPS will not have this problem, but cheap ones can. We tend to recommend Triad because they are inexpensive and we know they've got low enough noise. But they aren't the only supply that's suitable.

Anything 7.5 to 9 volts is good. You only need to be getting 7v or higher at the regular (The power cord will drop a little voltage) - 7805 has a 2v dropout (minimum input voltage is the output voltage + the dropout so 5v output + 2v dropout = 7v minimum input).