SNES sync issues

[Tiido Priimägi]

The brighter the image, the worse things get, or so it seems... I'm using RGB there, and composhit as sync on a PAL TV... I have tried direct connection on the composhit pin, and use of a capacitor. With capacitor things remain good looking on higher brightnesses thandirect connection. I've tried some resistors too, series, parallel etc, with no positive results.

What can be done to preven this sync messup ?

[Link83]

Are you using a PAL SNES or an NTSC SNES?

If its a PAL SNES you need to use 75ohm resistors to ground on RGB and Composite video (No capacitors though) although you may have already tried this? 

[Tiido Priimägi]

I forgot to mention that its a Japanese model. I've tried a lot of things, no positive results... I have not tried buidling a small video amp yet.

[Link83]

There was this thread a while ago:-
http://nfggames.com/forum2/index.php?topic=3263.0
Not exactly the same issue, but still a problem with a Super Famicom and sync, and on the second page phreak97 said:-

i used to have a snes that had a funny kink in the horizontal at the top of the screen, turned out to be cos i was using a power cable that wasnt powerful enough. it was also dc, which would have been ok except it was 9v, which ends up as 7.5ish after the rectifier, which is probably marginally ok for the regulator, but i guess it wasnt backed with enough current..  a much worse scenario than what you have, but it's not impossible to affect just a part of the video by having the incorrect power.

Do you perhaps have another power supply you can test it with? (You probably already know this, but the Super Famicom needs DC10V 850mA, centre negative) Just thought it might be something to consider.

[Tiido Priimägi]

I'm definitely not having a power issue, the AC brick can givesout nice 14V and 4A and so does my other one, same issue happens with both....

I will try the video amp route soon, hopefully it'll fix it... I haven't yet drawn a schematic of SNES video part anyway

[Tiido Priimägi]

bump

Fixed... my problems came from removed RF modulator... it has a small resistor in it which is between composhit and ground... without that, things will be pessimal... damn sneaky Nintendo, making RF hatin' Europeans' lives more complex

[RGB32E]

Will you give us an updated picture of the same game and screen? 

[Tiido Priimägi]

when I get my camera working again.... it just died.... D:

[Tiido Priimägi]

You need 2 resistors, a 2.7Kohm one going to GND and a 3.3Kohm one going to VCC on the composhit signal when you have removed the RF modulator.