This is a RF modulator replacement for the longboard Commodore 64 variants - these include ASSY# KU-14194HB, 250407, 250425 and 250466 - for ASSY #250469 and Commodore 128 variants see C128/C64 shortboard RF replacement. Note ASSY #326298 is not compatible with either of these RF modulator replacements.

The RF modulator replacement not only provides a better than stock video output but also includes a slew of extra features:

• Onboard S-Video output (chroma attenuated to 300mVp-p) for direct connection to a modern S-Video capable display or upscaler
• Signal passthrough to the mainboard AV DIN connector for mono audio, composite and luma/chroma output (for Commodore luma/chroma compatible monitors)
• Adjustable luma and chroma output [optional]
• Hard reset circuit [optional]
• Composite colour disable [optional]
• Adjustable composite mixing [optional]
• Direct luma/chroma connection from the VIC-II [optional]
• Direct audio output via 3.5mm TRS connector - this can be wired for a standard single SID (mono) setup or a dual/stereo SID setup*
• Hard reset button*

"*" The 3.5mm audio output and hard reset button share the same space on the PCB (where the channel selector switch would normally be), as such only one can be installed on the board. Installing the 3.5mm audio out is recommended, the hard reset circuit can still be utilised with a case mounted tactile switch.

All components are through-hole and should be readily available (no need to worry about any parts shortage), you may already have most of them on hand, but please pay special attention to the S-video connector and audio connector - these are of a specific type selected to provide the best fit in the C64 case. A bill of materials available to download with example part links, most of which you should be able to source locally from your preffered parts supplier.

Please see the GitHub project page for more info

UPDATE: 9 MARCH 2023 - Changed ground layers from solid to grid - makes soldering a little easier