New Commodore 64 RF modulator replacement - better video, stereo support, and more

Looks great! - Looking fwd to building a few of these.

Really nice!

👍👍👍👍

Really nice! Does it work with ntsc and pal? Thanks!

Nice job Mark. A very well thought rf modulator replacement packed with useful features. I'll definitely order a few and hope I'll find some spare time to build them.

Amazing contribution !!!. Thank you so much for this. During my next holidays I'll make three for my 1xbreadbin + 2x"C models". You are amazing 🙂

Absolutely awesome. An excellent example of shed design at work. How many compute units does this have?

Instead of doing external chroma/luma with two pads you cut and a pin header, just use two pin headers with jumpers on them. One side has the board inputs, the other goes to the buffers. To use external, you remove the jumpers and put wires from the VIC on the buffer side. This would also allow you to loop anything you want into the chroma/luma path. Should fit in the same amount of board space too.

Would it improve the signal quality if you use a shielded cable like from an audio cable for the luma/chroma shortcut with the shielding connected to ground on one end?

Thank you very much for this video Mark! Very interesting. Cheers from Canada!

Really well designed board.
I need one for my C64c.

Excellent work, exactly what I've been wanting to see for a long time. I will definitely be building at least one (for my C128 Neo), and probably more. Thanks so much for making this!

These boards look great Mark! One of the first mods I did to my original C64 (when I got back into retro four years ago) was to build a modulator replacement PCB. I ended up using the TEBL modulator replacement as it had pins to do the chroma/luma bypass direct to the VIC-II. I agree that there does seem to be a noticeable image improvement keeping these signals away from others.
I think I'll add your boards to my next PCB order from my favourite vendor 🙂

Great project and presentation... I will do it for my long and short board Commodore 64s... Many thanks...

I have 2 C64 machines, one Breadbin, and one C64C. Both running with Copperdragon analog RF replacement board. I got a pretty decent picture on the C64C, but not so great with the Breadbin (still much better than the original RF modulator) The Breadbin had a 6569R3 on it, so I thought the latest version (R5) might be better, bought one, and yes, it was much better but still not as good as the C64C. Being me, I bought a 8565R2 and modified the voltages on the board accordingly, and finally yes, a clear picture "almost" as good as C64C. That "almost" part have been bugging me to this day and when I saw the 100p - 200p thing on this video, I said "there it is!" for a brief period but then you said that the cap had nothing to do with the S-Video output. I have looked into buffering video signals with discrete transistors before and in fact that's how I did the composite video mod on my Sinclair Spectrum. It is a cheap and effective method. I will study the schematics (if you have them) on your Github and order a set of boards from PCBWAY to test them out. But on the contrary to your result in the previous video, I am quite happy with the Copperdragon board. This may be because I don't have anything else but the original RF modulator to compare it with, which is the main reason I want to test your design. A small note on the design, if you ever make a second revision, please do not make those solder jumpers preconnected with a trace in between, much easier to solder/desolder them than trying to cut the tiny trace in between without slipping and damaging other stuff. Great work, I appreciate you making it public big time. Maybe you may want to do another video on this where you explain the working of the circuit too. Thanks!

thanks for sharing the PCB. Can you link to the red tool you use to adjust the legs on the resistors?

Very cool! Thanks for sharing the board instead of charging $$ for it. Thanks for sharing

Hey Mark, love your work here! I'm curious on your choice of 2n2222 transistor compared to the BC547 and 549s used on other modulator replacement boards. Did you find the 2n2222 to provide a cleaner output? Or maybe was it just a matter of the pinout differences better matching your desired board layout? Thanks for designing these, I certainly plan on building a few!

Nice work bud. I love your designs and dedication. Will this solve the ghosting effect? 250407 I'm going to try to just change the 470uf capacitor in the modulator for now (so I've read) and damn man u have Gianna sisters working mint with your mod... that's a hard one:)

Thanks for the community support in making this open source! I've ordered a few of the PCBs and will look forward to putting something on my own channel (Reviving Retro) once I receive them. I have a few systems using Copperdragon so this will be a nice change and rad channel topic. I'll integrate it into one of my C128 NTSC units since you mentioned their sparsity across the pond there!

Great work. Nice to have another replacement and this one looks well thought out with comparison to existing options.👍

Your board seems to really improve the picture quality...very nice. I have tried Mr. Aranas RF Out board whiche gave me a terrible ghosting effect on every Monitor / TV set I have used. Does your board also improve the picture quality on CRT devices? Would be really nice if you could show the improvement on CRTs. Thank you for your infomative and entertaining content. 👍

Very nice. All I need now is a C64!

I saw in the video you installed the replacement unit on a the 250407-01 (A Board) with the 8 pin video, so my assumptions are it would also work fine with the 250425 (B Board) and 250441-01 (B-2 Board if you can find one out in the wild). Does it work with the "original" version 326298-01 (with the 5 Pin Video composite only Output)? Sure would be great to be able to get S-Video out of that puppy!!! All in all impressive and excellent work!!!

So timely :) i was planning to do something like this with the second C64 I acquired. Great work as always!

Great project!
PCBs and parts have been ordered to build several of each variant. I want to build one for my SixtyClone, the Shuriken I’m using is okay, but it looks like the image is better using yours.
It will be interesting trying it out on my Commodore 128 'daily driver' as well, the image has never been very good on that machine and can use all the help it can get!
Then because, ‘why not?’ I’ll try them out on various boards laying around my lab space for fun.

I am really enjoying this project. 👍👍 Your PCB layout is crisp and clean, and the hard reset option is a great added touch! Now off to PCBWay I go...

I build one of this, exited about it. Image and color are great but I get gradient kind of movement on the image....(NTSC)

We owe you one: Nice build, Mark! 👍

Building one of these myself. Parts all arrived today. Ahh...i totally didn't pay attention when ordering all my bits n pieces and ordered the C option for the S-Video connector instead of the E option....woops. Think I'm still good? It'll be going in a breadbin sixtyclone *466.
It'll match my purple mainboard nicely as i got it done in purple too from jlcpcb. (nothing against pcbway, i just prefer jlcpcb) :)
Thanks for sharing your work. :)

This is a great project. Thanks for making it. I ordered some C64 Shortboard version boards. My Commodore 128 video was awful, and swapped in your board, it is much better. I missed taking a before picture. It was so bad I really never though to use the 128, as my Commodore 64s both looked so much better. This board brings the quality at least to as good as the 64s. I haven't actively compared the 128 to the 64s with their RF Modules still installed. I was going to do the Chroma/Luma bypass, but the improvement without doing it is so good I didn't go to the trouble.

5 PCBs are $5. 10 pcbs are also $5 - lol

Question: Is you design optimized for PAL? If you look at modulator designs, the NTSC Chroma input uses coils and caps as input filters. Your PCB is almost part for part the same as the PAL modulator. I guess I will find out soon how well it works for NTSC.

Works fine with NTSC. You missed the 10K-11K load that the RF modulation puts on the Audio output. Without it, the audio output floats at about 2.5vdc. I added a 10K resistor from pin 4 to ground and audio output looks better and sounds better.

is not possible to have audio (mono) in the s-video output? and... why svideo and not rgb? maybe is not possible on the c64/128? thanks

I really like this solution better than the Copperdragon Analog board because of all the other features you've added. Very nice work and excellent demonstration :-) The SX64Man was gracious enough to offer me a couple long board versions of the modulator replacement. Bravo !

Question, if is possible to install this on the board with pin connectors? or using them will raise the high and will not fit the case holes?

Mods on my breadbin C64 and Alps 1541 have gotten out of hand. I've drilled SO many holes in the poor things. Please don't hate me!
C64: (Originally found by my daughter in a closet full of kittens she rescued from a busted drug den while gutting the property. It was covered in - it was a mess. It did not work. It had a bad SID, corroded keyboard, bad RAM.

VICII2 NTSC / PAL switcher
Reset switch wired to 556 dual timer IC
SIDFX (yes, with the 6581R4 AR)
FU32 dual beam tetrode vacuum valve headphone pre-amp (Broken apart and rewired so it all fits inside case, vacuum tube sits on top case, inputs / outputs, power jacks remote wired with shielded coax, holes cut and RCA jacks, etc mounted.)
JiffyDOS
Red / Blue IRQ activity LED
Ray Carlsen power supply. Get one from the man while he yet lives
Mechboard 64. Early C64-C white keycaps with front print. Cherry MX blue switches.
Lighter color "Made in England" case
Orange VIC20 Function keycaps
Potentiometer for left and right channels volume control
Four potentiometers wired to paddle controller legs of joystick ports for Cynthcart 64
A little OLED audio spectrum analyzer for use mainly with Cynthcart 64
Heat sinks everywhere
I think I might build this mod now! - thanks!

1541: (Came from same place. It avoided repair. It had a bad read / write head and cat urine destroyed much traces and such inside. I wound up cleaning it in dishwasher and ultrasonic cleaner then sending it to a guy on eBay that repairs 1541's - it could still be used for parts, bought a good working unit from him.)

RAMBOard
Parallel port burst nibbler mod with 15 pin game port socket in side of case
Switch Mode Power Supply - makes lighter, cooler
Track Display
JiffyDOS
Reset switch
Device ID switches

My datasette got no mods, only a rebuild + clean and lube.

I have C64 video question to ask you, but not exactly related to your project.
I have a C64 Reloaded Mk2, and I’m using the 8 pin DIN Video out, to the VGA Upscaler device I bought on EBay.
The NTSC 6567R9 VIC2 sits on the LumaFix64 Combo, which removes the jailbars on the screen. The downside is, it’s a very sharp image with the annoying checkerboard dot pattern all across the screen.
It gives a bit of a CRT retro look, but it’s annoying after awhile with some eyestrain. I was thinking about trying another NTSC VIC2 chip, like the 6567R8, to see if that checkerboard pattern will go away. Do you have any thoughts or suggestions? The Reloaded Mk2 does have the 4 Pin mini S-Video connector, I haven’t tried this yet; but don’t want to spend a lot of money for a RetroTink if no improvement occurs.
I have tried the PAL 8565R2 with the LumaFix Combo, and the image is perfect! No jailbars, no annoying Crosshatch dot pattern across the screen; although the boot image does appear to look a little dark.
I just need some suggestions to get rid of the NTSC crosshatch dot pattern annoyance.

I just ordered a 128 so we’ll see what it needs to be done!!!

Great Video , thanx