SNES sync issues after mod
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- This topic has 45 replies, 7 voices, and was last updated October 10, 2017 at 8:07 PM by
eric90000.
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August 20, 2017 at 7:20 PM #14558
So the original mod used vanilla CSYNC output from SNES (1chip or Mini?) with the same cable, and there was no sync issues? Is there a schematic for Voultar’s board? It seems TTL mode does not bypass csync to output but uses a buffer.
August 20, 2017 at 7:31 PM #14559Yeah it’s the SNES Jr/Mini, and I used something like this to mod it myself years back, though I don’t think I used resistors. Never gave me trouble, not on the Framemeister nor the OSSC later on.
This is what’s installed now
Kinda feel like I should have just left things alone now, except that my own mod wasn’t well done and needed professional repair work, some solder points were loose. Sync-wise it was fine though. In the meantime I’m getting in an older model SNES, just in case there’s no good solution to this.
August 20, 2017 at 11:04 PM #14562Yeah I think you need to remove that resistor from your cable. Does seem a bit problematic fixing that issue in the console when it’s been fixed in every SNES CSYNC cable before.
August 20, 2017 at 11:13 PM #14563I wonder if there’s a clean way to snip it out without ruining anything? Would I have to connect anything in it’s place, or just cut that connection? If it’s just a simple cut that’d be easy to test too.
August 20, 2017 at 11:30 PM #14567No should just be able to remove it and re-solder the connection.
August 20, 2017 at 11:36 PM #14569Alright so just cut it, and if no change solder it back in? I can try that later tonight or tomorrow.
August 20, 2017 at 11:45 PM #14570If the RGB bypass board has the TTL jumper shorted then you should not remove the resistor from the cable (should never be removed btw). Can you post a picture of your cable’s SCART connector with the components?
August 21, 2017 at 12:04 AM #14571Yeah I did take a picture earlier, forgot to post it.
August 21, 2017 at 10:29 AM #14576Ah ok sorry I misunderstood, if your mod is set to TTL, the resistor should be there.
However, it looks like there’s no resistor on sync line on your picture (yellow cable). Possible that you purchased it before this problem was known about as the TTL sync works in many cases it’s just not recommended.
August 21, 2017 at 10:42 AM #14578The resistor could still be in the console connector. But if its in there then you shouldn’t be having any problems.
Could it be that if there is no resistor at all it worked with the stock CSYNC from the SNES but now that its buffered the voltage is too high?
If you have a multimeter you can check if your cable has the resistor in it: https://www.youtube.com/watch?v=Z3sE3uk5kPU
August 21, 2017 at 10:46 AM #14579If there’s no resistor on the scart end, and the TTL jumper is on, then the voltage could be too high.
Try setting Voultars board to 75 ohm and leave the cable as is?
August 21, 2017 at 10:49 AM #14580Yeah, the resistor on the pic is not on the sync line, it’s the one for +5V (and should be there, passing 3V to pin 16). Looks like you should jump 75 Ohm on Voultar’s board after all.
EDIT: oh, there were multiple replies already 😉August 21, 2017 at 11:02 AM #14582I’m gonna be installing Voultars bypass board in my Snes mini in a couple of weeks. It’s regarded as the best I think so I can’t imagine there’s a flaw with it, I’m sure you’ll get it sorted.
I’m gonna be ordering an RGB cable from retrogamingcables.co.uk too, I’ll probably end up removing any resistor on the scart PCB and then setting Voultars board to 75ohm.
August 21, 2017 at 12:47 PM #14583Honestly it wasn’t even until recently that I started hearing about TTL sync, so I’m not even sure what my cable is. I did buy it a like the year before.
So if my cable doesn’t have that resistor, and my mod has the two TTL points soldered together, should I change anything? I’m getting confused on what should or shouldn’t be present.
August 21, 2017 at 3:40 PM #14587Honestly it wasn’t even until recently that I started hearing about TTL sync, so I’m not even sure what my cable is. I did buy it a like the year before.
For a stock Super Nintendo, the RGB cable should have a resistor on the sync line, that’s the yellow wire on your picture. Unless that resistor is hidden in the other end of the cable (unlikely) your cable doesn’t have it.
The most likely reason it doesn’t have it is because this issue wasn’t widely known about until recently. The standard TTL sync signal will work on most equipment, though it’s not recommended because the voltage is higher than spec. The fact that it’s producing some weird results with your OSSC isn’t terribly surprising since the signal is not to spec so could be causing any number of issues.
Your Voultar board is set to output TTL sync, the same as a regular Super Nintendo, so really you need that resistor on the sync line.
Your options are:-
1) Reconfigure your Voultar mod board to output 75 Ohm sync rather than TTL sync. Some folks argue this is best since the less components in your SCART cable the better.
2) Order a newer SNES SCART cable from Retrogamingcables.co.uk, or add the resistor to your existing cable yourself.
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