TV used as monitor Schematic help

[Lego614]

I need help with this. I am building an arcade machine and came across this schematic to convert RGB to .... something. I don't know how it works or if it is compatible for arcade machines or will work on a tv. If it won't I would like a new schematic to do this.




EDIT: I am NOT using a computer/emulation, this if for a REAL arcade machine.

[MonitorGuru]

This will work if you have a newer TV with YCrCb (Component or as Toshiba calls it "ColorStream") inputs.

That's a simple RGB to YCrCb converter.  It uses arrays of resistors to take the right "mix" of each color to create the Luminance (Y), Cr (Y-R) and Cb (Y-B) signals.  It also features sync "cleaners" which allow you to supply a nice clean H+V sync signal into the luminance wire, with adjustable pots to get them just right just in case the board doesn't match up exactly with the syncs the TV wants.


This will work good for going into component video. It won't be quite as clean as pure RGB, but should be noticably better than SVideo, since you're starting with pure RGB.

This is also the circuit that you need to hack into the chassis (not neckboards) of most newer TV's (including those that don't have component input) since they use color separate video everywhere on board right after the input processing IC. But as has been discussed before here.. that is not anything you want to do unless you have the schematic of the TV.

But to connect up with consumer component jacks on your new TV, this will work nice.  Shouldn't even need to up the input signal strength (though you may have to cut it down, I dont know if this circuit was designed for .7 volt computer output or 5 volt game output.


Edit: Since I see the words "VGA" here, I presume this was designed to take PC VGA output and send it to a TV.  I am not quite up on my sync knowlege, but I don't think it's doing anything funky like converting the high PC refresh down to low TV..you'd have to make sure the card was put into the correct refresh rate to begin with.  Therefore this circuit will probably require .7 volt VGA output, and if you drive it with 5 volt arcade board output, you will likely overdrive it, and you'll need to put some circuitry in to limit the range of the output of the arcade board.

I've considered building one of these, but just havn't gotten around to it yet.

[TalkingOctopus]

I was interested in the schematic so I did some googling.  Here are some notes by its creator:

http://www.keohi.com/keohihdtv/interfaces/diytranscoder.html

Be sure to note the schematic errors he points out.

[darklegion]

Here is another design in case anyone is interested(attached)