Jitter Master System and Mega Drive

[wumbo64]

I have and issue with a Mega Drive 1 and master system 1, the jitters up and down its really bad and makes the games unplayable.
I am using Retrogamecables scart leads for both consoles.
I’ve tried direct connection and through a switcher both with the same outcome.
I have also fiddled with settings but nothing seems to help.

On the front of the OSSC it says RGBS 313P 15.55KHz 49.69Hz (with a green sync light)

Also i am running lots of other systems with out a problem (PAL and NTSC N64s/SNES, PS2, XBOX, Gamecube)

Any suggestions would be greatly appreciated!!

[megari]

Have you already tried the settings here? This should help at least in the case of games using interlaced modes. OTOH, I see your mode seems to be 313p, which is progressive.

Are your Mega Drive and Master System unmodded systems? What games do the jitters occur with? Can you perhaps provide a Youtube video of what you’re seeing?

[wumbo64]

Jitter video

They are both unmodified, i have only tried it with Alex Kidd (built into master system) and sonic 2.
They do the exact same thing as you can see in the video.
I have messed around with the LPF but nothing appeared to make a difference

I am using the cables that have a sync stripper built in, Do you think this may be the issue?

Thank for the quick reply

[megari]

Hmm, that might be normal. At least Sonic 2 uses an interlaced mode. Interlaced content deinterlaced using OSSC’s fast deinterlacer has a kind of a jittery effect. Have you tried setting the “480i/576i proc” setting to Passthru? This would use the deinterlacer in your display, which may give a better picture at the cost of higher latency.

Have you already set the H-PLL coast options as directed in the link in my previous message?

[BuckoA51]

Hmm, that might be normal.

Definitely not for Alex Kidd like that.

I am using the cables that have a sync stripper built in, Do you think this may be the issue?

Seems possible, where did you get these cables from?

[megari]

Definitely not for Alex Kidd like that.

Hmm. Does Alex Kidd use a progressive video mode? If that is the case, the jitter is definitely not normal.

@wumbo64, what does the LCD on the OSSC say when you play Alex Kidd? What is the voltage level of the sync signal when using your cables? If it’s 5V TTL, then you should modify your cables to lower the voltage level to avoid wear on the components of the OSSC.

[wumbo64]

The cables are from retrogamecables, i believe they are the ones with the sync stripper in.

The lcd read out for alex kidd is in my original post.

I will try a couple of the other settings later today

[Harrumph]

Get new cables, sync stripper is not needed for OSSC and does not improve the signal quality anyway.

[Galdelico]

@Harrumph – I was gonna buy a new C-Sync RGB cable for my Japanese MD2 (mainly to see if it will alleviate the jailbar issues I always experienced with my system) from Retrogamingcables.uk, as they seem to have upped their game and overall improved their products (according to the retro community feedback at least). They don’t seem to mention sync strippers anymore, and they specifically state their new RGB cables are ‘OSSC compatible’. Should I look somewhere else anyway, or am I going to be safe?

@megari – Where do I read that voltage information on the OSSC? I tried to explore the info menu, as well the sync one, but with no luck.

Thanks guys. ^_-

[paulb_nl]

@wumbo64 Can you open up the SCART plug and share pictures of the inside? There should be a resistor on the output of the sync stripper.

[wumbo64]

i can open one up this evening and get the info.
So you think new cables without a sync stripper is worth a shot?

[wumbo64]

Here are the pictures,
Scart1
Scart 2

[megari]

Hmm, there seems to be a 470 ohm resistor (appropriate for dropping the voltage from TTL level) and a 220 µF capacitor in series with the sync line. I don’t see a sync stripper. Maybe the stripper has been moved inside the connector at the console end?

What console and what version (PAL/NTSC?) did you use the pictured SCART lead on? Maybe someone more knowledgeable than me can comment on whether the 220 µF capacitor on the sync line is appropriate for that one. I’ve never seen a capacitor placed between the output of a sync stripper and SCART pin 20.

[megari]

Is this cable what you have? Please note that there is no mention of a sync stripper.

[paulb_nl]

That cable in the images he posted is just a CSYNC cable without stripper. Retrogamingcables always have the sync stripper on their PCB inside the SCART plug.

Voultar made a video where he recommended a 470 Ohm resistor and 220uF capacitor on the CSYNC line for Genesis cables.

Next step would be to try tweaking the various sync settings in the Sync options menu.

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