Flickery Screen US SNES Mario World...?

[egparadigm]

Hello!

I've just whipped out my modified US SNES (50/60 and region switches) and on Mario World the screen flickers on certain levels. It seems to happen most often on a level with lots of verticality. The screen jumps about and adds and subtracts black lines to the top of the screen, so you lose the bottom off the edge.

Can anyone diagnose this? I am wondering if it might be insufficient ampage on the power supply. My adapter cable has broken, so I'm using a switchable Maplins power supply. You only seem able to select the voltage, which I have set to 9v:



SNES says it needs 10v 850mA

Could this be the reason and anyone know if I can adjust the mA on this?

I don't have the instructions and it's been a while, so bit nervous of fiddling about ? was surprised when I managed to get the SNES to even switch on the other day!

Thanks all...

[speedlolita]

That supplies 3.1A at 9V - which is more than sufficient. It will only draw what it needs.

You could try moving the notch a little so its at 10v, or it might simply be that the SNES is sensitive to the power supply. I can't imagine it is of the highest quality after all, being a Maplin product.

[egparadigm]

What happens if you supply too much voltage? I.e. Accidentally 12.

[speedlolita]

Worst that could happen is the fuse blowing I think, but 12V is within what the machine can accept.

[smouty]

Have you tried another cart?
SMW does not like region switching.

[briareos_kerensky]

Does your power supply deliver AC or DC? IIRC the US SNES require a DC power supply, not AC like European SNES.

[egparadigm]

Other carts are OK, but like with Mario World, it could be buried in specific levels. Might do more testing.

I do have the region lock set on, and also tested the refresh rate switch.

Yes, the power supply is DC as per. I normally use an adapter for a UK mega drive power supply, but my shoddy soldering came apart.

[egparadigm]

Tried 12v and initially it seemed like it had solved problem, but after extensive testing it's still happening. What's odd is sometimes when I play it is worse that others – or it could be related to jumping about in the right part of the level. The beginning of the Cheese Bridge level is a good testing ground.

Here are some example pictures:

Bad:



Normal:



Not the end of the world as I can manage to negotiate these levels in the mean time. Just odd.

[egparadigm]

Alright, I'm pretty sure it's not a power supply issue now, as I have resoldered my adapter back together and am now using an MD PSU.

Perhaps something has come loose – the region lock, scart cable? Does anyone recognise the symptom?

[nakamura]

I would recommend testing another unit first.

[egparadigm]

I do actually have a spare US SNES and a PAL modded unit at home... Maybe I can grab them one day soon, and the necessary PAL carts and gamebit.

[stoofle]

I had similar issues years go running a PAL Mario World cart on a PAL SNES with a 50/60Hz switch...I just assumed it didn't like running at the different frequency.

[egparadigm]

Ah, maybe that points at the problem.

Bit different as it is US cart in a US machine running at 60. This particular machine was a bit of a bodge job on my part – I accidentally snapped the chip leg off when attempting the mod. Ended up using hot glue to secure the solder wire to the very tiniest bit of leg that could be accessed from without.

If it's not connected the machine is in 50Hz, but I assumed this was still good since I would expect it to be either/or 50/60 – more likely 50 if it's loose.

[randombs]

Clutching at straws as my school's blocking the images but:

When I used to mod Saturns I often found that leaving a leg not connected to anything at all produced vastly different results to properly grounding it. Can't remember screen flickering but I definitely had strange electrical problems.

I did a SNES once and that had weird stuff happening until I found out one of the wires got caught in the shielding although that was just short-circuiting. Have a poke around!

[egparadigm]

I'll have a look in due course – thanks for the suggestion. I suspect all of this stuff should be properly earthed as, bodge aside, it was one of the more professional jobs I've done.

I'm wondering now if it is down to the loose connection and that maybe the greater power required by bigger levels causes it to flip out slightly. WIggling the 50/60 switch sometimes positions the image in the same way.

I am curious to know what the usual issues are with Mario World being played on an out-of-region machine.