Very Weird Sync problems on Gamecube on a CRT

I recently bought a sony pvm-20L4. All my consoles are outputting RGB via scart, which is then converted to RGB and sync bnc with LR audio.

I've been testing out all my consoles to see if everything is running fine, and everything is.

Except my gamecube...

The gamecube has some very strange issues with picture and sync which doesnt happen on my lcd tv, watch the video some dude posted for a brief explanation.

https://www.youtube.com/watch?v=zA1RpYCUOyI

The tv loses sync and goes to green at specific times.. Does anyone know why? How can this be fixed?


Also, when I put the sync BNC cable in the "out" socket instead of the "in" it solves the issue for the gamecube, but causes all my OTHER systems to experiece exactly what the gamecube experienced!!?!

How weird!?!

Do any of the geniuses here know whats up?

I can give more details on exactly what im using if needed.

 

^^ looked at the clip, it's pretty rough.
that's a CRT so, i couldn't really comment..
BUT i've had a similar effect on my sanyo LCD with the artifacts and green flicker!
in my case, the screen isn't compatible properly with the xbox original, so that's plugged into an electronic channel selector for purpose (only the one item plugged into it) as it seems to normalise image.
without it, it goes to hell fast!
just the xbox is this issue!
is the TV itself compatible with NGC Y.U.V.? (rgb) do you have another tube to test on?
what's strange, the same type of config you described made things work/not work for the rest!
bear in mind, this is on my LCD, not a CRT.
if you have an intermediary, like a VCR or a scan liner/doubler on passthrough, give it a bang there.
if i didn't know any better (and that's a VERY strong possibility) looks like the TV either isn't decoding the signal properly! (can't see the cable/console being the issue if vice-versa test are successful)
....
apologies if this is no help at all, just thought i'd share my experience on a very similar ordeal, even if it's on an LCD..
..
hope you get a solution, cue the experts! :friendly_wink:
[edit]
typo

 

Amiga youre becoming one of my favorite users on this site, thanks so much for the quick reply!

Q: "is the TV itself compatible with NGC Y.U.V.? (rgb) do you have another tube to test on?"
A: i literally have no idea what Y.U.V means, and i sadly dont have another tube to test it on, but the person who did the video isnt me, so thats 2 people with the same problem


Guys the exact specs im using for the gamecube are as follows..

>SNES/Super Famicom/GameCube RGB Scart cable (BOUGHT FROM) http://www.consolegoods.co.uk

>Female RGB SCART to BNC adapter breakout cable (BOUGHT FROM) http://www.retrogamingcables.co.uk/sony-pvm-scart-converter-bnc.html

>Region free PAL model 1 gamcube (BOUGHT FROM) user Marmotta on this site

>Sony pvm 20L4 (Very good quality few hours on tubes, colour and alignment all good)

 

^^ seriously, thanks a lot, means LOADS! :friendly_wink:
i'll cut back on the TLA's..
Y.U.V. is RGB, just the first is the international standard of recognition!
your setup is scart so there's RGB there as you stated above.
there's slight variations on signal output, unlike HDMI or SVGA/DVI which are more a less a generic signal across the board, for anything less, that's where slight variation of signals can occur.
not sure if it's a 'non-standard' or lower than HD why this happens but the high-end resolutions are a standard across the board, meaning you can hook uo ANY nationality of item to any nationality of screen without any difference!
unfortunately, the same can't be said for lower resolutions.
...
highest to lowest output types as follows...
1, HDMI = can't top it and it's an international stadard! (down to screen to support output sizes, not refresh rate..immaterial on HD)
2, SVGA/DVI (the same) = pretty much the same above, just a different socket/signal type!
3, Y.Pb.Pr./component = usually, most screens globally suffer no issues here, but it can happen...as with my xbox mentioned above. (only using an electronic passthrough seemed to work, without it, oh dear)
4, Y.U.V./RGB (the same) = YOUR SETUP AS INDICATED ABOVE. the lines are blurred as to what will be compatible or not. what may work on your setup using the same socket/resolution doesn't really apply to others across the globe, vice-versa. (doubt powergrid refesh would have a bearing there, but i'll not rule it out)
5, s-video/supervideo (the same) it gets worse, this is a really common problem, same as above line.
6, CVBS/composite (the same) really no need to go into details here, the above covers it!
7, (NULL/VOID) RF/UHF/VHF (in terms of the screen the same, just a different input signal known as radio) strangely, a better chance of this working on an overseas screen for input as it's radio frequencies, but the overscan may say different, powergrid refresh rates may apply?
...
LCD's have fewer issues there vs CRT's! :cocksure:
[edit]
typo

 

If you connect your console's composite output BNC to the display's sync output BNC, you get a short circuit... Bad idea.

You should either connect the composite BNC to sync in, or composite in. Or maybe the GC is outputting sync on green and you don't need the composite lead at all.

There are a few technical reasons sync could be lost like that. Ruling out user error, to know for sure would require knowledge of the SCART cable and SCART adapter construction, as well as the GC's output circuitry to rule out electrical incompatibility.

 

fair enough, i wont be doing the output trick anymore then..

When i remove the sync bnc cable it still doesnt work.

So you dont know how to ix this issue then?

 

RGB from the PAL Gamecube only supports composite video as sync. There is no clean sync if your monitor needs that.

 

fair enough. So based on my specs as mentioned before, what do i need to go about resolving this issue? £10 donated to the site if this issue gets solved for me and the person who uploaded the yt video.

 

I don't think I've seen a quite perfect ready made solution. Sync Strike is close, but takes a cable adapter (the output plug isn't SCART).

 

:'C

 

I'm using the SyncStrike ( http://arcadeforge.net/Scaler-and-Strike-Devices/Sync-Strike::15.html ) and this vga>bnc cable with my pvm2950qm: http://arcadeforge.net/Scaler-and-Strike-Devices/VGA-DSUB-15pin-HD-auf-BNC-Kabel-2m::77.html
Some consoles need the external 5v from a power supply, some not. Works pretty good.

 

Just a quick update to say that my 3 way madcatz rgb scart output works fine

i have no idea why

 

bump

 

Your old cable probably has inappropriate wiring or components.

 

Well I guess one could modify the cable to add a LM1881 chip. Beyond my ability of course.

 

? It probably has a wrong pinout such as wiring composite sync to composite video, or perhaps it has the SNES SCART's inappropriate pull-down resistors, or maybe redundant series capacitors which are internal to the GC (both would seriously screw up the signal's frequency response).

BTW, in no way does a LM1881 "clean" sync as popularly reported, people are using them to simply slice sync from composite video, exactly the same as most monitor's sync inputs. If the signal is severely distorted by the frequency response, there's no way the 1881 can slice it correctly. The only reason the 1881 occasionally "fixes" sync over the monitor's real sync input is due to the real sync input's termination, which is very problematic for non-compliant high-impedance sync signals from video games.

 

Then how do you separate composite video from sync, if I am right about the problem here? I just said PAL Gamecube does not output composite sync.

 

Displays use circuits similar to those internal to the 1881 (but sometimes more advanced). The 1881 contains nearly the simplest circuit necessary to slice sync and it's not robust against noisy or distorted composite video; there are many 1881-compatible chips that have significantly more advanced circuitry and do a better job. With the plain 1881 you're actually supposed to put a filter at the input if you're going to use it with composite video. My point is that since monitors generally have the same circuits inside a 1881 is rarely necessary for any situation, yet it's become just a silly fix-all to people. In most cases where a 1881 fixes someone's problem, the problem was actually with the electrical connection (high attenuation or bad frequency response) and is the console's fault, not the display's.

Something like a PVM probably has very robust input circuitry inside, but if the sync input is terminated and there are improper components in the signal path, that could still lead to a bunch of electrical issues, even with advanced circuitry. The 1881 might "save the day" simply because people don't terminate its input.

 

i dont speak AVspeek, i only speak english.

any chance of a translation or dumbed down solution for fixing my problem?

 

You fixed the problem with a new cable did you not? The solution is to use the right cable.

Some people are building SNES/"N64" SCART cables wired to composite sync instead of composite video, that might be the problem. Or it could be that people build SCART cables with resistors and capacitors inside, which might be right for SNES but wrong for the GC which might have them inside the console instead of in the cable (I dunno). If the signal goes through multiple sets of resistors and capacitors, bad things will happen to the signal.

For the future you should use cables which simply use composite video as sync for your PVM unless you're sure the composite sync signal is electrically compliant. Composite video coming out of consoles is always electrically compliant so it can always be used to drive a sync input properly. Composite sync is typically not compliant (I don't know of a single console which outputs compliant composite sync)--the drivers do not have the current capacity to drive a terminated input so they require an amplifier (or a 1881 outside the console, paired with a current boosting amplifier, if you don't want to stress the 1881).