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New - C64 Replacement RF Modulator Design by Matt Barszcz

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.

#SIXTYCLONE C64 Replacement RF Modulator

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

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

C64 Replacement RF Modulator
Available as a kit £15 or Assembled £25 plus postage.

Uses genuine Bourns components, not equivalents.

Email for more information or to order.
Available from Stock.
Updated June 2022


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