by Sean Kelly
This is a rather feeble attempt at describing the hack to the ColecoVision video game system to give separate audio and video outputs to the system. I am what I call an "Electronics Tinkerer" meaning I have no formal education in electronics and basically only know what I have been able to figure out by ripping apart everything I own!
I am a collector of Classic video games and systems and ran across this hack on one of the many ColecoVision systems I own. It actually works quite well and gives the on-screen images a much crisper look to them. Audio is generally pretty poor on the ColecoVision and this hack doesn't do much to help it.
In order to get things started you have to open up the ColecoVision by removing the 8 screws on the bottom of the case. With the screws removed, the case is still something of a pain to open because of the lip on the expansion port, but just keep working at it and it will eventually come apart. Next thing is to remove the screws holding down the motherboard itself (three of them I believe) and take the motherboard out of the case.
On some versions of the ColecoVision the aluminum cover is soldered to the circuit board. If this is the case on yours, you will have to desolder it and remove both the top and bottom parts to the aluminum cover. Set everything but the motherboard aside and you are ready to get to work. The person that did the hack on this system uses a small automotive-type fuse block terminal to mount the components of the circuit board on. I have located it in the 1992 Radio Shack catalog (page 150) and it is RS part #274-688. It comes in a package of four for $1.29. Here is a list of the components used: AGAIN - I have no formal electronics education and don't really know how to read all the weird symbols on the parts. I will do my best to describe them (I have also labeled them on the line below for future reference - take note):
We're looking at a total of about five bucks to do this so for parts that do not come in packages of two or more, I would suggest buying an extra one, unless you know what you're doing, in case you screw something up. The center connector on your terminal will be the ground for all the components because it is the only terminal that sticks out on both sides of the block. The part the extends on the bottom will be used to mount to terminal to the ColecoVision motherboard. Directly to the right of the RF modulator (big silver box on the motherboard) right under the letter of the revision of the motherboard (the one I am looking at is "J") you will have to scrape off a section of the green coating so you can solder the terminal on the bottom to the motherboard. After soldering this bend the terminal block so that it is standing straight up from the motherboard.
Since many of the components will be "tied" together, you might want to connect them all to the posts first and then solder them later. The way I am going to describe how to connect them will (hopefully) make it as easy as possible to understand. The following is a listing of each post numbered from 1-5, left to right, looking at the terminal block from the back of the motherboard. Looking at the "back" you will be looking at the channel 3-4 switch as well as the RCA plug that is used to connect the ColecoVision to the TV/Game switch now.
Here is what goes on each post:
You now have one leg of the transistor (T1), one leg of the resistor (R1), and one leg of each capacitor just hanging there right? Connect all of these together, but do not connect them to any of the posts. Just sort of let them hang there.
The person who did this to my system also has one other wire connected to the bottom of the motherboard, but the other end of it has been cut and is not connected to anything. I assume this serves no purpose.
Copyright (c) 1994, 1995, 1996 Joseph M. Huber and James Carter
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