New - C64 Replacement RF Modulator Design by Matt Barszcz

C64 Replacement RF Modulator
Design by Matt Barszcz

The C64 RF Modulator replacement based on the schematics of similar designs like Zero-X/OMS's Modified Commodore RF Modulator Design and JMP$FCE2's S-Video only design. This board can be used to replace a damaged or defective RF modulator in your C64, to improve the sharpness of your video output, or as a modern solution to replace the composite/luma/chroma output functionality of the original modulator on new motherboards such as the SixtyClone or Bwack’s KU-14194.

This design has a few goals that set it apart from the others -

• It is a universal solution that fits and is electrically compatible with both the C64 and C64C without having to change components on the board or run jumper wires for power.

• It is easy and inexpensive to build with only a single, small PCB and all through-hole components.

• It provides high quality S-Video (Y/C) output while maintaining composite video output for compatibility.

• It provides adjustable luma/chroma output levels to fine-tune the S-video signal. This allows for the best possible compatibility with a wide variety of different board revisions, VIC chips, aging components and monitors. Adjustable levels mean this board can also be used with s-video cables with or without an inline resistor to eliminate “checkerboarding” caused by too high of a chroma level.

This RF modulator replacement is compatible with motherboard revisions 250407, 250425, 250466, and 250469, and both NTSC and PAL VIC-II chips. It should also be compatible with Bwack's KU-14194 board since it uses the standard longboard RF modulator. 

It is not compatible, however, with the early revision 326298-01 boards with the 5 Pin AV Output. This revision uses a different modulator pin layout, and the video signals are not combined in the modulator. They are instead processed with discrete components inside the VIC-II can.

The assembled C64 Replacement RF Modulator is supplied in six colours to match your PCB! Black, Blue, Green, Purple, Red & White.

The C64 Replacement RF Modulator is also available as a kit in six colours to match your PCB - Black, Blue, Green, Purple, Red & White. 

The kit includes your choice of PCB, all the components necessary and a comprehensive assembly guide to assemble the C64 Replacement RF Modulator and uses genuine Bourns components, not equivalents. 

The Kit is also available in six colours -

For more information please visit https://github.com/mbarszcz-pcb/c64-rf-modulator-replacement

C64 Replacement RF Modulator

Available as a kit £15 or Assembled £25 plus postage.

Uses genuine Bourns components, not equivalents.

Email sales@sharewareplus.com for more information or to order.

Available from Stock.

Updated 1st January 2025