page 3 of 5

This part is where things get a bit more complicated.  First, we need to get to the video signal.  Unlike the Intellivision, the Colecovision doesn't use a stock off-the-shelf RF modulator, so accessing the composite-video signal involves popping the top off of the RF modulator and tapping the signal from the pads shown here.  Fortunately, there's a test pad right next to pin 3 for us to solder to, and the grounding shield can be soldered to the metal enclosure.

The Colecovison's video signal isn't particularly strong, so don't try to get away with the cheap audio cable here; use some well-shielded coax cable, with a proper braided shield, to keep the signal as clean as possible.  Some 75-ohm coax antenna cable will do nicely, and you can probably get a 4-foot or 6-foot cable-TV hookup wire from the dollar store as well.   (There's not a lot of room in here for a thick, heavy cable, so try to use smaller-diameter "mini-coax" cable if you can.)  Just be careful to keep the shield-braid from shorting against anything – a piece of heat-shrink, or some electrical tape, will come in handy here.

You will need to trim away a bit of the RF modulator's shield canister to get the cable out.  Fortunately, the metal is soft and not terribly hard to trim; even a decent pair of wire cutters will handle it with a little patience.  (You could also use a Dremel tool or some other kind of cutter on the lid, but I'd recommend against using it on the canister itself; too much risk of cutting into the circuit board or getting bits of metal lodged in the wrong place!)  While there's probably not that much risk of the cable moving around enough to get cut once everything's put back together, I used a couple of pieces of foam tape to cover the sharp edges of the cuts, just to be sure.

Last, we pick off +12Vdc to run our video amp from L6, here.  Why here, instead of just splicing right into the red wire from the power connector?  Because the +12V here at L6 comes off the power switch, so the video-amp board will be turned on and off along with the rest of the system.

Oh – why +12V, and not +5V like the Intellivision modification, you ask?  Follow to the next page and find out.