RGB to Component Transcoder

[mesmer]

Has anyone built this circuit? "Circuit Diagram 4 (RGB to YUV)"http://elm-chan.org/works/yuv2rgb/report.html
Looks like it would be a cheaper alternative to jrok or neobitz.:
http://www.jrok.com/hardware/RGB.html
http://neobitz.com/Pages/Mods/SystemMods.aspx

My intended application is to use a PC with Soft15khz or an ArcadeVGA, feed it through the transcoder to a CRT SDTV with component inputs. Has anyone done anything like this?

Looking here: http://members.optusnet.com.au/eviltim/ ... ga2arc.htm
I see that:

PC video (VGA, running special software)
Video amplitude: 0.7Vpp
Video DC offset: yes
Video input impedance: 75
separate horizontal and vertical sync
sync polarity changes (can be set in software)

Since it is DC offset, I believe I can remove the area inside the dotted line of the circuit. Does this make sense?

Also, looks like I need CSYNC for this circuit. For this I will do:
Since I know this will be CSYNC from VGA, and not Composite Video, I should be able to leave out the LM1881N too, right? CSYNC would go straight into the BJT i guess.

Really debating messing with all this, or just buying an ArcadeVGA + jrok.

[antron]

I use this: SCART to component transcoder

I love it, so far it works great with Genesis, PS1, PS2, SATURN and 90% of my PCBs with a SCART supergun.

Gradius Gaiden looks like an emulator on my large LCD tv. Huge clear pixels. On a CRT it looks sharp as well.

You would still need a sync combiner for a PC. If thats all you want, some video cards have component. I wonder if some will do 240p?

[mesmer]

Cool, that would work too, not too expensive. Just need to make a VGA->SCART cable.

I believe for component out on the video card, it would scale from the res you are at to 640x480, then interlace to 480i. I do have a component dongle for my card, I should double check.

[antron]

I purchased a VGA(DB15) to SCART cable, just to find out that the H and V syncs were on some unused data pins of the scart cable. I moved the H to the C-video pin. I have an extron converter that outputs c-sync and fed that on the H line.

The bottom line, this converter can take c-sync, but you'll have to make your own cable (or adapt one)

Some devices/monitors can take H and V twisted together as C-sync. It may be worth a try for a PC.

[speedlolita]

jrok looks like it may be my answer in regard to PC Engine to component..

Want to have a setup on my LCD TV sort of like:

TV -> Component 4 way switch box -> consoles & jrok -> scart switch box plugged into jrok with consoles in.

[ZOM]

^^ IIRC the JROK has huge problems with the PCE, some of the earlier ones even gave just a green or yellow-ish(?) screen. No one really knows why...or at least it was like that a while ago - I dunno if the problem got fixed. Anyone?

[speedlolita]

Maybe the one antron has would be better then.

Looks alright to me.

[mesmer]

Oh, I don't mean PCE. I mean a PC VGA card, like an ArcadeVGA http://www.ultimarc.com/avgainf.html or similar in software http://wiki.arcadecontrols.com/wiki/Cus ... Soft-15khz

[viletim]

mesmer,

That's correct, you can omit the clamp and sync stripper parts of the circuit if you only intend to connect a PC. The simple diode/resistor sync combiner will do the job (so long as the polarity is negative) and the output of this shoud go to Q4, just as you suggested. Notice that Q4 is not an ordinary BJT but a 'digital transistor' - it contains a couple of imbedded resistors.

I've built this RGB > YUV circuit myself and had ti working without any trouble, though I used a linear power supply instead of the DC-DC. BTW, The server doesn't seem to allow hot linking of images, use http://elm-chan.org/works/yuv2rgb/report.html instead.

[neorichieb1971]

I have a transcoder for sale if anyone wants it. I am willing to negotiate on price.

Its got a 2 pin 110v AC adapter with it.

[mesmer]

Viletim, thanks for the report. I updated the link too, thanks.