Very strange SNES portable problems

Website · Post by **Life of Brian** » Tue May 27, 2008 11:07 am

I have three games which do not work on my ZN-40 SNES portable. Donkey Kong Country, Super Mario Kart, and Super Mario All-Stars. Donkey Kong turns on, but the controller does not work. Super Mario Kart turns on, controls work, but when the racing starts the screen is garbled and any time I accelerate I'm out in the grass immediately and Lakitu is putting me back on the track with his fishing pole. And for Super Mario All Stars, it turns on, screen looks fine, controls work fine, until I start up one of the games like Super Mario 3, at which point the controls do not work.

This was all very curious and I thought it might be due to a wire on the cartridge port coming loose. However, I tested all the connections and they're fine. I also tested these games on the second ZN-40 SNES portable that I've been building for someone, and I HAVE THE EXACT SAME PROBLEMS. All other games I've played on both systems work perfectly with no problems. None of these games have a Super FX chip (StarFox works just fine), and the cartridge port on both portables is connected 100%, so what could be the problem? All three games work perfectly on an unmodified SNES connected to a TV.

One thought is that it might have something to do with the controller. I have it connected directly to the SNES controller's IC as shown in this diagram by Turbo. When I was testing the new portable the controls worked for a couple of minutes, and then they became unresponsive and the system started freezing. After a little bit of investigation I discovered a tiny piece of metal connecting two pins of the controller IC. If something that small could cause the system to freeze, perhaps those games in question need some of the not-connected pins.

Edit: Wow, easy solution for such a long-winded post. I connected pins 10 and 11 and now Donkey Kong and Super Mario All-Stars works. However, I still get a garbled screen on Super Mario Kart, so it seems that must be a different problem.

Turbo Tax 1.0 · Post by **Turbo Tax 1.0** » Tue May 27, 2008 6:32 pm

weird, I have had some problems with dkc in the past let me check it out

you may want to check and see if the pin I have labeled as N/A is connected to the pin I labeled "white"

not sure what will happen but on my standard snes controller they are connected together

good luck

Website · Post by **Life of Brian** » Tue May 27, 2008 7:15 pm

I had noticed the same connections - pin 12 to pin 6. I tried connecting it, and while it did not affect anything negatively, it did not help. I've never needed it before for any other games.

The only similar game I can think of is F-Zero, which is a racing game that stretches and moves the background around to simulate 3D movement just like Mario Kart. However, it works without a problem.

I just can't seem to think of a connection that is normally found in an SNES that I haven't duplicated that would affect the game in such a way. However, the rest of all my games work on it so I guess it's not too big a loss. It makes me sad though because Mario Kart is one of my favorite games.

Thank you for the suggesting Turbo. Has anyone else had a similar problem like this, or have a suggestion?

GoldenfrankO · Post by **GoldenfrankO** » Sat May 31, 2008 10:36 am

your SMK problem might be the fact that the games dirty/broken. Test it in an original SNES and see if it does the same gargled screen.

mothatrucka · Post by **mothatrucka** » Sat May 31, 2008 10:40 am

Pretty sure someone as experienced at this as LoB would have already tried that.

See?

All three games work perfectly on an unmodified SNES connected to a TV.

Website · Post by **Life of Brian** » Sat May 31, 2008 4:33 pm

Yes, the game works just fine - it's got to be something with the portables.

bacteria · Post by **bacteria** » Sat May 31, 2008 6:23 pm

It is quite probable that a later version is not 100% identical in its workings/software to the original version of a console, which would account for the problem.

Rekarp · Post by **Rekarp** » Sat May 31, 2008 9:01 pm

I say wire a Unmodded controller to the thing and see what happens. My portable SNES had zero problems with those games. The garbled screen sounds like something is wrong with the cart slot but you checked that all ready... At a loss on the problem.

On mine I piggy backed two 4021's and used 10K resistors and had the brought high with 5 volts exactly like how the NES controllers work. Switch grounds the line.

Website · Post by **Life of Brian** » Sun Jun 01, 2008 8:29 am

Ah, but there's the mystery, bacteria - the other unmodified SNES I tested it on was a mini SNES, and it worked fine on that. I think Rekarp's idea makes the most sense - I'll try that next.

Such an odd problem. Why did it have to be for one of my favorites?

Rekarp · Post by **Rekarp** » Tue Jul 08, 2008 1:06 pm

Life of Brian wrote:Ah, but there's the mystery, bacteria - the other unmodified SNES I tested it on was a mini SNES, and it worked fine on that. I think Rekarp's idea makes the most sense - I'll try that next.

Such an odd problem. Why did it have to be for one of my favorites?

Did you ever figure this out Brian?