SNES 50/60hz question

[BuckoA51]

Still very much in the process of assembling my ultimate games room, I've been experimenting with my SNES a lot, and after ordering a new fully wired SCART cable my picture quality has gone up a great deal, however there's one problem still...

I have a 50/60hz modded PAL SNES and when the console is set to 60hz I get some instability on the top of the picture, along with more dotcrawl type noise on parts of the picture too. At first I thought this was due to the quirkiness of the XRGB3 but I've since discovered it happens when the machine is hooked into the DVDO Edge too. If I switch back to 50hz the problem vanishes immediately. This is true regardless of whether the actual game cartridge is a PAL or NTSC version.

Could this be a problem with the 50/60hz mod in my SNES or is there another reason for this?

[Mikey]

Well I've modified a few SNES' and I've never had a problem at 60Hz that wasn't there at 50Hz too. Try it connected directly to a TV's SCART socket to see if the problem persists.

[BuckoA51]

Try it connected directly to a TV's SCART socket to see if the problem persists.

Directly connected to the TV the problem is less noticable, the wobbly sync problem goes away but there is still a difference between 50hz and 60hz with regards to dotcrawl though directly hooked up to the TV you can only see it when you get close.

Botched 60hz conversion then, or is this normal? Or maybe that SCART cable I praised wasn't as good as I first thought, though I find it hard to think it's a cable problem when the picture is solid at 50hz.

[neorichieb1971]

I remember reading once at Ravengames website that there were 2 scart cables for SNES. One for NTSC machines and one for PAL machines.

I gather there is a configuration set up difference in there somewhere causing the adverse effect in 60hz.

On the other hand. Even if your system is 60hz its still a PAL machine, so maybe i'm talking nonsense.

[BuckoA51]

Even if your system is 60hz its still a PAL machine

Yeah that's pretty much what I thought too. Maybe I'll order a switchless mod SNES and see if it makes any difference. Worst case I'll have a spare SNES I suppose...

[Mikey]

It could be that your TV is switching to composite video, giving you dot crawl in 60Hz mode, though I can't imagine why that would be. The switching voltage would be the same at 60Hz as at 50Hz. If you have another TV, you might want to try it with that.

Most, if not all of those RGB SCART cables you buy now don't have the switching pin wired up at the console end, so in the SCART end they wire the blanking pin across to the switching pin with a resistor to make the TV switch. That's not how it's meant to be.

The next thing would be to try a different SCART cable. If the result is the same, then I'd blame the 60Hz mod.

[BuckoA51]

Two SCART cables produce similar results. It's weird, at 50hz when I look close I can see like a checkerboard type effect on the intro to the game Lemmings, in the sky and on the lemmings hair. As soon as I flip the 60hz switch the checkerboard starts moving. I don't think it's as bad as if it was changing to a composite signal but it is weird... plus at 60hz there's the picture instibility I see on the EDGE and the XRGB3 (can't test the XRGB at 50hz just yet mind since my TV won't handle it).

[BuckoA51]

I'm actually starting to suspect that the DVDO Edge doesn't handle NTSC Via SCART all that well. This isn't such a big deal, since I am eventually going to be using the XRGB3 for all my NTSC needs anyway, but it is nevertheless interesting. When I feed my Sega Megadrive into the DVDO Edge via SCART and turn it to NTSC, I get intermittent horizontal white lines flash across the picture, as if the scaler can't decide on a row of pixels and just spazzes out. Switching back to PAL and everything is fine again. This combined with the SNES problem (although I can see the SNES problem a tiny bit on the TV without the Edge) makes me wonder if the SCART input in the Edge is actually all that much cop.

Also, when feeding a SCART signal to the Edge, if I press the "Info" button, under "signal type" I can see the text changing from 720x240 @ 59.59hz to 59.51Hz. It does this about once a second, even more frequently in PAL mode, is this normal?