A few questions from an RGB rookie

[Jibbajaba]

I picked up a Sony PVM-1341 not too long ago.  I have a friend who is really into playing classic games in RGB, and he was always telling me that I should get in to it.  So when I was able to get this little Sony monitor, I figured that was my chance.  He lent me all of his RGB cables, which he uses with a Commodore 1084 monitor, so I just made an adapter that would allow me to plug his cables into the BNC jacks on my monitor.

Unfortunately the time has come where he (understandably) wants his stuff back.  After playing all of my systems in RGB, I can't go back to composite, so I need to hurry up and make my own.  I tried looking at his cables to see how they were made, but he paid someone else to do the work for him so I can't ask him any questions because he knows nothing.

I figured I would make the Genesis cable first because it seems to be the simplest, but even then I have read some conflicting information.  I have read that I just need to make a straight-through cable with a Genesis-style connector on one end and whatever I need on the other end.  Then I have read that you need to add some caps and resistors to the cable.  Finally, I took apart my friend's cable and it has an IC chip stuffed in to the 9-pin hood.  So which is it? 

Second, I want to make the cable for my Playstation.  I have a PS2 component cable that I would like to use in making the RGB cable, simply because the connector has all of the pins present, whereas a normal AV cable will not.  Also the cable is nice quality, where the SCART RGB cables I see for sale on places like PlayAsia look pretty thin.  What I don't understand is how the stock cable takes the signals at the pins on the console and turns them in to a component signal.  I freely admit that I am not totally clear on how component works, but I think I have a basic idea thanks to what I have read in the web.  My question here is this: Is there some sort of IC or something inside the hood of the playstation-side connector on the cable, or can I just cut the cable before it splits off into the separate connectors and add my own connector?  I know I need to add caps and possibly an IC to strip the c-sync out of the composite.  I guess what I am asking is if I cut the cable, are there going to be individual wires in the cable connected to each of the pins that I need, or is there some stuff going on inside the connector hood that I need to get rid of?

Lastly (for me) there is SNES .  My main problem with the SNES cable is going to be getting the console-side connector.  Would it be better to just go to Gamestop or something and buy a couple of GameCube AV cables, take them apart to remove the pins, and then assemble one fully-pinned connector?  It's either that or buy a  SNES/N64/GC SCART RGB cable, but like I said those don't look like they are very good quality.

The bottom line is that I want to do this once and do it right, so any extra help that can be provided would be greatly appreciated.

Thanks!

Chris

[Endymion]

This is a lot easier than you are making it out to be. The cables do not "turn the signal into something else." The signal should be RGB at the console end, and RGB at the monitor end, period. The only exception to this, where any change should be made, is to strip sync from video, and this is not necessary in every case. It isn't necessary in the case of the Genesis at least, and since you want to start there that's a good place to go.

Get on ebay and order a SCART RGB cable. Make absolutely certain that the cable you get is both SCART, and that it is RGB. Realize that SCART is not RGB, SCART is just a plug which can carry RGB, so if your product description states both SCART and RGB you are good.

When you get the cable, leave the Genesis side alone. It's done! No alteration is necessary there. What you will do instead is open up the SCART side and using the pin diagrams on this site, label the wires one by one with a piece of tape and a sharpie, R, G, B, Sync, and then you are done. Go to Radio Shack or order the connector that your monitor uses, then lay the wires out in the way your monitor pin configuration has listed in its pinout and you will have RGB. Simple huh?

[Jibbajaba]

Thanks for the reply.  Would it be easier to modify the SCART cable, or to just make a SCART -> BNC adapter for my monitor?  Also, SCART cables do or do not already strip the sync info?  I assume not, but am not sure.  Assuming that they dont, could I just put the lm1881 chip circuit inside of the SCART -> BNC adapter, so that I only had to make the circuit one time?  Also, if I made that adapter, I could have the audio leads just come out of there...  Now I'm just thinking out loud I guess.  Sorry.

Thanks,

Chris

[RGB32E]

Would it be easier to modify the SCART cable, or to just make a SCART -> BNC adapter for my monitor? 

Sure, depending upon your preference and the type of connection on the monitor.  If you're monitor uses BNCs, it'd probably be easiest to make an adapter, assuming you can locate a female SCART plug.

Also, SCART cables do or do not already strip the sync info? 

No, SCART RGB cables for video game systems carry the sync signal over using composite video (composite video contains composite sync).  Though if you're using a Sony PVM, its extremely likely that it will strip the composite sync from composite video, so no sync stripping circuit should be required for your monitor.  Also, the composite video signal on the SCART connector (to be used as sync signal) is on SCART pin 20.

Also, if I made that adapter, I could have the audio leads just come out of there...

That's all you! 

[Endymion]

Yes, simple manual SCART switches are also very cheap on ebay and are a good way to go. They give you plenty of room to work inside if you need to make any alterations (strip sync, audio, etc.), but a lot of people just starting out want to get right to it, sometimes just to see if the difference they get is enough for them to care. But if you go the extra step of getting a SCART switchbox along with your cable then any cable that you acquire in the future you'll be able to just plug up. Sounds like you get it now, get to work.

[Jibbajaba]

OK I ordered a SCART swtichbox and some cables from UK eBay.  I can just add the sync-stripping circuit to the switchbox when I turn it into a BNC adapter, right?  Is there any reason why I can't get the sync signal for the Genesis by pulling it out of the composite signal instead of using the dedicated sync line? 

Thanks,

Chris

[Jibbajaba]

I just wanted to sort of finish off my topic so that it might be useful to others in the future. 

I ordered SCART RGB cables for the SNES and Genesis off of eBay.  Had to import them from the UK but thats OK.  I also ordered a SCART switchbox, but unfortunately the seller had misrepresented it as having all of the pins wired which it did not.  So I decided to ditch the idea of trying to use the SCART connectors at all.

My monitor has BNC connectors in the back for the RGB signal, so I bought a 15-pin VGA --> BNC adapter at an electronics store.  This way I could just make my RGB cables with a 15 pin VGA connector on the end.  I think it's better to do this because if I get a new monitor down the line, I just have to make an adapter to go from the VGA connector to whatever the new monitor would have.  This method also allows me to use a VGA switchbox so that I can keep everything hooked up.

The first cable I made was the Genesis cable.  Unfortunately, this cable requires 3 caps and 3 resistors on the R, G, and B lines, plus a cap on the sync line (may not be required, but I read a post where someone recommended it.  Trying to stuff all of that stuff into a 15 pin connector hood is basically impossible, so for awhile I was just using the cable without a hood.  But my anal-retentive side wouldn't allow me to continue doing that.  So what was I going to do with all of that stuff that wouldn't fit in the hood?

This is where my VGA switchbox comes in.  To do this, you need one of the older mechanical switchboxes, not the newer (and normally nicer) electronic ones.  The three consoles that I most want to be able to play in RGB are the Genesis, SNES, and PSX/PS2.  All of these systems require caps on the video lines.  So I figured that the easiest way to take care of that would be to put the caps on the RGB output lines inside the switchbox.  This way, the Genesis cables just needed three resistors and one cap, which will easily fit inside of a 15 pin hood.  This also means that I can just wire my SNES and PSX cables straight through without adding any craziness inside the hood.  I don't know if the caps will interfere with systems who's cables don't need caps, but if so then I will just make the cable according to specs and just bypass the switchbox. 

I have read some people in these forums mention that the caps should be close to the console (either in the console connector or inside the console itself).  This doesn't make any sense to me from an electronic standpoint, and it certainly isn't making a difference in the performance that I can tell.  So far I have completed the Genesis and SNES cables and the picture is beautiful.  All I still need to do is order a PSX cable and wire that one up.

So in conclusion, ordering SCART RGB cables off of eBay is definitely the way to go.  I was impatient and wanted to build the cables myself, but all that accomplished was wasting time and money.  As far as the caps go, I would definitely recommend putting them into a switchbox, which also ads the benefit of not having to plug and unplug cables from the back of your monitor all the time.  One last piece of advice would just be to make sure that you order cables that have that little deal in the middle of the line that has audio and comp video outs.  This makes things a lot easier because then you just need to worry about wiring up the video signals at the end of the cable.  I don't think you can get a cable like that for the Genesis 1, but it doesn't matter because you don't get stereo sound out of the back connector anyway (I get sound out of my SegaCD, but you can also just use the headphone jack.)  RGB is definitely worth the trouble, and even if you are totally new to wiring things up and using a soldering iron, this is a great reason to learn.  Once you play your old games in RGB, it's HARD to go back to anything else.

Thanks,

Chris