PC Engine jailbar research

[viletim]

Still haven't found a solution after 8 years? I installed a homemade RGB mod on the Duo-X, coreGrafx2, TurboNanza on the CoreGrafx1, and SuperGrafx—all of them still have small jailbars visible on the OSSC or GBSc. I've replaced capacitors in various combinations. Using a good shielded cable and high-quality power supplies doesn't help. I tried soldering a very high-quality original component cable from an Xbox 360 directly to the TurboNanza and outputting the RGBs to the GBSc—that didn't help either.
The PCengine is the only console where I haven't been able to fix the jailbars yet.

The PC Engine's digital to analog converter is sensitive to noise, so you need to place some relatively large (1u) ceramic capacitors near it. That's the most important thing to do.

You also need install a video driver circuit. Make sure the ground connection to the video driver is close the DAC (HUC6260A), then the video output connector ground connects to the video driver circuit. If some other 'ground' point is used for the video amplifier or video output connector, it may share return current with a RAM chip or something and you don't want that.

It's also worth mentioning that some of the video amp designs floating around are not very good. Anything that has a resistor connected between the power rail and the video input for biasing is no good because it mixes power supply noise into the video signal.

[MaRCer]

Capacitors 121 and 135 have been replaced with 4.7μF ones. I also tried replacing 133, but that didn't help.
I'm using a TurnoNanza RGB mod, which takes its signals from the expansion port. The jailbars are much less noticeable, about the same as the third gray ramp screenshot from the previous page. They're also about the same as the modified Genesis va0-2 and Genesis va4, without the subcarrier pin raised. Which pin controls the subcarrier on the 6260?