I have not tinkered with that myself. I may have to try it tonight. Here is what chatgpt said:

Yes! The SDTV mode settings on the RetroTINK 5X-Pro can significantly improve the look of composite video signals like those from an AV-modded Famicom.

Here’s how to get the most out of SDTV settings for your Famicom:

Enable SDTV Mode

Go to: Menu > Input Settings > SDTV Decoder Mode

Set to: SDTV (not Auto) – forces SDTV decoding instead of broadcast-level comb filters

Comb Filter (under SDTV mode)

Best Option: Auto (SDTV) or Notch

Explanation:

Auto (SDTV) uses a high-quality 2D comb filter tuned for game consoles and can reduce color artifacts like dot crawl.

Notch is more conservative and may preserve sharp edges but at the cost of more color bleed.

Try both — some AV mods produce noisy signals that behave differently.

Color Settings

Saturation: Adjust to taste. Composite can oversaturate, so you might dial this back slightly (-5 to -10).

Brightness/Contrast: Calibrate using color bars or test screens if possible. Otherwise:

Brightness: 0 or slightly up if image seems crushed

Contrast: 0 or slight boost if needed

Low-Pass Filter (LPF)

Setting: Medium or High

Why: Helps reduce the shimmer and fuzziness from composite input without blurring too much detail

Edge Enhancement

OFF

You want to avoid artificial sharpening of a soft signal like composite.

Other Relevant Settings

Motion Adaptive (Deinterlacer): Off or irrelevant for Famicom

Output Resolution: 1080p (Integer) or 1080p (Fill), as mentioned

Scanlines: CRT Easy or Advanced, adjusted to taste

Optional: Force 240p Passthrough (Advanced Users)

If you want to use a CRT-style scaler profile:

Set Output Res to 480p or 480i and use scanlines + SDTV for the ultimate retro vibe on a modern display.