July 26, 2016

Yurkie's Colecovision Composite Mod Kit

I have been playing my Colecovision more often the past couple of years and have had pretty good luck with the RF output until recently. It just started really getting crazy with a lot of interference. When I'd mess with the cable at the back of the system, it'd get even worse. I thought it might be from a broken solder connection, so I opened the case and tried a few things without any luck.

That's when I realized it was probably time I did a Composite mod... There are a bunch of ways to do this I've learned, but I had heard good things about Yurkie's mods from AtariAge, so I decided to go with his DIY kit.

As you can see, Yurkie's mod uses a nice single 3.5mm jack for all three RCA cables.
I haven't had good luck taking photos of screenshots for video output comparisons. It seems like my photos make the RF look better than it does in person and the Composite worse than it looks in person, but I did make a couple of side-by-side shots that will hopefully show a bit how much this mod kit improves the video output.

Here are a couple of photos of the RF before the mod:

This is how it looked when I was messing with the cable.
If you look close, you can see the lines, but also, in motion, this was really wavy.

As far as the kit goes, it was really easy for me to install and I swear, the hardest part is getting the case separated! I won't document that here, because honestly, I just worked with it until it came apart and it took me a good 30 minutes or so. Here is a disassembly guide that might help with that also, if anyone out there is interested.

Yurkie's PDF install guide should be enough for anyone doing this mod themselves. I didn't have any problems at all following his guide available in his AtariAge post I linked above.


This kit utilizes a sleek 3.5mm to RCA 3 cable, to avoid having to drill 3 RCA jacks, which I find really nice. This cable was included with my kit.


Here are some photos I snapped while doing this:

First I desoldered the grounding shield.
While I had the system opened, I decided to spray some CRC Contact Cleaner in the power switch.
Here are the 4 solder points needed for the mod.
After soldering the wires to the RF board and C88 cap leg, I drilled the case with a 9/32 bit and used wire cutters to cut a small notch for the wire exit when the RF lid is placed back on. Below I try to show where on the case to make the drill hole for the 3.5mm jack. I removed the motherboard completely from the case when doing this, so I wouldn't accidentally damage it. 


Here you can see the finished drill hole and notch cut in the RF box
Almost assembled!
Here's a backside view with the RF lid in place.
The RF shielding needs to be cut so that it doesn't touch the new installed board. I cut this whole rectangular chunk out before placing the shielding back on.
And that's it! I put everything back together and was almost floored when I fired the system on. The image was very stable, bright and crisp! Here are some side-by-side photos, but keep in mind, the RF looks worse in person, because it MoVeS and the Composite output looks even better than in the photos and is very colorful and stable. These were taken on a cheap little LCD, but it looks even better on a CRT.

If you look closely at the bricks, you can hopefully see the difference!
The motion blur on the enemies isn't really noticeable to the eyes, that's just the way my camera snapped the motion.

In a nutshell... If you're still using an unmodified Colecovision and aren't happy with the RF output, I'd suggest contacting Yurkie over at AtariAge to try to snag one of these DIY kits. For $30 and some time, it's totally worth it, IMO. My thanks to Yurkie! Cheers