HISTORY This all started when I picked up a 1702 monitor. Those chroma/luma jacks on the back got me all fired up to finally do the 2600 s-video/stereo mods (which turned out great). The 5200, 7800, and O2 were next and they went without a hitch. After that the only systems I was still RFing were my intv1 and colecovision but I couldn't find documentation on the web. Started fiddling with my intv1, burned it out somehow, then picked up two more. Messed with one in the lab at work 4 nights straight with no luck, finally on the fifth night I found out the transistor was bad (DOH!) After all that, it was a nice surprise when the colecovision worked with almost the same circuit, that was a one-night project. Anyhow, I'd figured this should be written up for the next guy looking for this info. Those wavy lines won't be missed in the least. There may be other circuits to do this better, or with less parts, this is just something I got to work. You can always ignore this and refer to the other online documen- tation which is well ... nothing. If you try this, you do so at your own risk, yadda yadda yadda. I've destroyed some systems myself; it builds character :) SCHEMATIC + 5V-----------,---|(----, | 100uF | | \/ GND | 10uf `------,--/\/\/--,--|(--, 1.6K | 10 | + | ,-/\/\/-` | \/ GND | ___/-----` Video + | /|/c\ in ---)|---+------(b| )3904 100uF | \|\e/ + Video | \---,--|(----,---() out | 2K | 100uF | `-/\/\/-,-/\/\/-` | | 75 \ GND \/ spst \ | C_filt | ,-----|(-----` | \/ GND Audio + Audio in --------------|(------------------() out 100uF General Comments This circuit was an adaption of the chroma/luma mod from the 2600 FAQ. Basically it is the luma mod changed to capacitive coupling at both ends. A shunt capacitor was added onto the output to filter down the harsh colors (the color information is the highest frequency part of a signal and capacitors have a high-pass effect). The optimum value may vary according to TV's so a switch was added to remove it. You can always turn down the tv's color setting instead. Too little capacitance means strong colors, too much makes a black and white signal. You add capacitance by putting smaller values in parallel You can solder the AV cables in directly or mount RCA jacks onto the console case. Either way, remember to ground the shield (outer conductor) Once you do a AV mod, the RF output really become ugly, because the circuit acts like an rf antenna, so don't be surprised Colecovision Specific Components put flat on small radio shack board which sits on top of metal enclosure. RCA jacks put of right side of console near the back. C_filt value -- I used 0.0147 uf, 0.015 might work or might give black and white signal 5V and GND signals-- can get from top right-hand corner of main board: L9 GND ------ () () ------ 7 1 ------------- C22 | .| | U17 | | | ------------- 8 14 VCC (bottom left pin of IC) Video and audio-- lift up top of smaller metal enclosure, see rows of solder terminals X X -- audio Video X | X XXXXXXXXX X X XXXXXXXXX X X Intellivision Specific Intv1's require a lot of work. If the RF video looks OK, maybe you should leave it alone. They also have an internal transformer with 120V connections so don't shock yourself or start a fire. RCA jacks put on back of console. Have fun getting that metal enclosure unsoldered (intv-1) or finding room for things (intv-2) People in the newsgroup say the intv-2 video output is strong enough to drive TV's directly. I tried three different ones and they all had wimpy video, maybe it's a west coast thing. C_filt value -- 0.015uf (Pitfall has the nastiest colors so it makes a good cart to check with) Video = modulator pin 1 (counting from edge of board) Audio = modulator pin 3 Intv 1 5v Bottom of C20 (farthest from edge of board) Gnd Go to bottom of R22 (farthest from edge) Right over to C17 Right one more to empty terminal with thick trace Intv 2 5v Go between lettering for U12 and U13 then a little to the right (light green) Gnd Right side of C20