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Stereo output via monitor port, only if you give up composite.


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I mod the video outputs on my 600XL(s) in a simple and effective way. It's cheap (almost costless) and it improved the picture about 95% and good enough for me to work on a nice big CRT.


See the first schematic.


However, when I hooked up an incorrect RCA plug of my video cable today I realized that with this set-up the composite output still carries the Lumicance signal, which is not necessary at that pin and it is also useless when hooking it up to a composite input as it give a terrible picture.


Since I also don't like unnecessary cables, I figured I could make good use of this now free pin...


If you are like me and use one of these standard 5 pin DIN connector to 4 RCA plug cables (which are a LOT cheaper than any "dedicated Atari" cables you find on the net.....), AND you have Stereo Pokey in your machine, then it's a good idea to let that fee pin carry one of the audio signals.




So, I removed R124 and L12 so that the composite out pin (pin 4) was now completely free of any signal.


Next I wired the RIGHT channel of the Stereo POKEY PCB to the top solder hole of where L12 was. This is a neat way to connect the right audio channel.


Now....the left channel of the Stereo POKEY board is always (hard) connected to the original audio circuits (amp) so in theory I could left that as it, however, since the Stereo POKEY has it's own amping on both channels, I figured it would be better to hardwire that to the original audio out pin, which will now be the LEFT audio pin), pin number 3.


To do this, remove R114 and R122 and solder a wire between the LEFT sound output of the Stereo POKEY board to the TOP solder hole of R122.


To be honest, it would be best to hook up shielded wires with the shield connect to the ground connections of the Stereo POKEY board. You can leave the shield of next to where you solder the wires.


Alternatively, if you already have the RCA connectors at the back (or a 3.5mm stereo jack, like I have) you can simply jumper the wires from there to these locations. This way you have two possible options of connecting: when using a TV you always use, simply use the monitor cable....when you want to hook up your high-end audio set....use the RCA's or 3.5mm jack :)



Of course, this same mod can be done on 800XL and probably all other machines, but you need to find the "same" spots where to connect the wires.....



Remark: the colors of the RCA connectors are not going to be logical....you can either measure them (with a DVM in diode test) OR simply try them out which is which....you won't harm anything on your TV by swapping them....




Edited by Level42
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  • 3 months later...

LOL.... i stopped working on this for a while and had to reference my own thread......


Matty: not that hard, in fact Jon does it "all the time".


And it's what I'm going to do too since I recently bought a Sophia RGB. So the little 3.5 mm jack is going to be removed from the spot of the modulator/RF output hole again....



However, im still modding the old video connector like this....just in case I don't have to use that one....in unknown situations ;);)

Edited by Level42
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