c0pperdragon verdict

By Michael Doornbos

March 10, 2021 - 4 minutes read - 818 words

Ahh, the quest for a better Vintage computer picture never ends. I’m having fun with it anyway.

Side thought: At what point does a computer cross over from old: no one wants that 2007 Windows tower you built in your basement, to OMG, it’s Vintage, let’s drive up the eBay bids to the stratosphere!!!!

How bad was it?

Original picture from my 64C PAL Machine. Muddy with jailbars, but I’ve gotten used to this over the years

For the most part I didn’t notice the marginal picture on these machines until I started capturing them and sharing some of my ideas on the internetses. The above was the result of a rather difficult piece of code to write given my current skill level (my first line of Assembly on any processor EVER was in October 2020). While I’m used to poor picture quality from a C64, it suddenly felt weird to share this on the internet.

I was an Aviation Electronics Tech in the Navy and since then spent the following 20 years in tech startups. Surely I’ve learned at least something over the years right? (maybe not) It was time to get my hands dirty and do something about this.

RF Modulator replacement

A couple of my Commodores have okay pictures, and most of their trouble can be narrowed down to the marginal design of the RF Modulator cans.

Luckily there is an inexpensive and easy to implement solution for this. My writeup on it is here. I’ve installed three of these since then and I have nothing but good things to say about them.

RF Mod in my flat 128, results were more mixed on this board since it made the jailbars nice and clear ;-)

At 16 Euros, the price is good too.

Resist the chroma

There are many commercial cables that have a 280-300 Ohm resistor on the chroma line of the video on a Commodore. Adding this made a dramatic difference for my setup, eliminating a TON of noise in my cheapo video capture device.

My capture device blows out all of the sharp lines and adds this weird rainbow effect that isn’t obvious on the monitor, only the capture device

Yes, I realize these two shots are different resolutions, I forgot to switch the capture device back from PAL here. The difference is still clearly shown though

This cable is available in many places if you don’t want to make one. Be sure to check the “add resistor for $2” option.

Component Video Mod

I was determined to have at least one out of this world picture for Video capture of many of my posts going forward. Sure I can use “The C64” or my Ultimate 64 for this, but with all of my talk about how the real thing somehow feels better, I wanted one of my vintage machines to be a viable option for screen captures.

I had ordered this component video mod before I replaced the RF modulator and added a 300 Ohm resistor to the chroma signal on my video cable. The picture was so good at that point I wondered if I should even bother with the full Component video mod.

Since I already had the old can RF modulator removed on this machine and pin headers soldered in the right place, removing the RF Modulator and installing this took less than 10 minutes.

I did have a minor scare that I had bent a pin on my VIC-II chip, and by minor scare I mean panic at the disco level scare. Turns out I didn’t and it was just dirt on the pin. Phew.

It’s a tight fit with a few of the caps, but it does fit if you’re patient.

Lesson to past self (like 2 hours ago in the past). DO NOT RUSH these kinds of things.

Better?

How much better is the picture?

Crazy better.

There are ZERO jail-bars and the colors and lines are almost perfect.

Here’s a shot of the LCD with my iPhone so you can see individual pixels.

This is probably about as good as is possible from this machine

And just to compare the original picture:

Please ignore that this checksum is incorrect

This is the exact same machine. Incredible.

Downside?

The only downside is that technically this is no longer the output from the original hardware. The built in FPGA takes the information directly from the VIC chip and builds a signal with that. If you’re bothered by that, then this isn’t for you.

Is it worth it? I think it is.

It’s open source hardware, which is my favorite: https://github.com/c0pperdragon/C64-Video-Enhancement

One more thing

Someone on Twitter just pointed out that the S-Video output still does work with this mod, so if you really want a marginal picture you can flip the switch on the back and go back to fuzzy jail-bar goodness.