rgb+scart+vga help!? want to hookup neo to hd tv

rgb+scart+vga help!?


ok here is what i have and what works.
1st i have a samsung hl-p6163w. it has a 15pin vga input jack.(and a dvi+hdmi)
the tv supports up to 1280X720p at 60hz and 1920X1080i 60hz.
my pc looks great using the tvs vga input
i also have a TVator II made by antec that converts analog vga to svideo and 15pin scart rgb.
it worked ok with the svideo output when i had my old tv 480i wega.
i know that pc rgb is diffrent than the rgb that consoles and arcade boards use because of the h&v sync signal.

i wanted to test my vga port on the high def tv to see if it would support the rgb signal from the consoles.
for the hell of it i hooked up my pc to the TVator II and the 15pin scart rgb port from that to my samsung hi def sets vga port.
to my suprise the picture came in!
the test seem to show that i could hook up my games system rgb to the vga port with no problem.
so i made a cable for my neo geo to hook it up.
all i got was a rolling picture............

my cable pin out
15 pin pinout
1 red
2 green
3 blue
13 h sync (tried both for the hell of it)
14 v sync
6,7,8 rgb gnd (not sure what ground to use tried both)
10,11 sync gnd

now i am confused... i thought scart rgb was the same as the rgb game systems used?
why did the TVator II scart rgb work but not the neo-geo...

do you think the TVator II just passes the sync signal through? so the h v sync from the pc just passed right through and made the pic stable on the tv?
or do i need to strip the v sync signal from the compsite signal from the neo geo?


it would be too cool if i could have a simple fix that would let my hook all my game systems to my hed def tv using rgb.

if anyone can help me i would be very thankful.


TVator II http://www.antec.com/us/support_productInfo_details.php?ProdID=64132#
samsung http://www.tvauthority.com/DLP-TV-HDTV/Samsung-HLP6163W.asp (samsung has no website for this set yet !???)

Dude, there is a very simple cicuit you can make up that splits the composite sync signal into H&V syncs. It's good that your TV supports 15Khz signals on its VGA plug!

Have a look here and cycle down till you get to "Composite sync to HSYNC and VSYNC" You will need to get hold of an LM1881N sync separater IC (plus 2 caps and a resistor), but these are fairly common to find.

I have tried this on my Sony HDTV and it does indeed work. The picture is glorious!

You can use this pinout too so you know what comes from the Neo geo. The 5v output is perfect for the circuit.

btw, I'd say that Tvator device you have splits the sync internally, that's why the picture is ok.

Dreamcazman said:

It's good that your TV supports 15Khz signals on its VGA plug!

Click to expand...

And where did you read that? The link he posted only says "PC input", which sounds to me as VGA or hi-res (31KHz or higher) RGB. It doesn't say it also supports low-res (15KHz) RGB. I'm not saying it actually doesn't, I just see no indication (in that link) that it does...

As for this TVator device, there's a manual in the link he gave and in this manual I read:

"The TVator Remote II is an external PC/MAC/NEC/iMAC DV-to-TV scan converter.
It can convert computer images into video format and display them on any
TV monitor or large-screen LCD projector.

Input signal: VGA, RGB or MAC
Horizontal frequency: 24KHz - 132KHz
Vertical frequenc: 50Hz - 120Hz
Output signal: Composite video, S-video, Computer monitor
(PC, MAC or NEC) pass-thru output

TVator Remote II should in theory support any computer and display systems
with a vertical display frequency range of 50Hz to 120Hz and a horizontal display
frequency of 24KHz to 132KHz."

This is enough to understand that a Neo Geo (i.e. a 15Khz RGB console) cannot be hooked up to this TVator, a device that does not accept a horizontal frequency lower than 24KHz...

Oh, and that part in the manual about "Connecting a scart RGB monitor" only refers to the output, not the input: that is you can connect a PC signal to the TVator input and then send the downscanned signal out to a scart TV (for European owners of the TVator).

can you tell me what mod you did from that page?

if you could do me a big fav and give me a hand sice it works on your tv.

15 pin wiring

1 red
2 green
3 blue
4 gnd
5 gnd
13 h sync pin 1 from LM1881
14 v sync pin 3 from LM1881

where does pin 7 from the LM1881 go?
pin 4 and the end of 6 tie to the same ground as the negative of the power supply? how do i tie all the grounds together from the tv to the circuit?


is this the mod you did? did you do the And and Nand part also?


Composite sync to HSYNC and VSYNC converter
Sync separation is a process quite often needed in video technology, but it is a little bit hard to find a chip which especially made for that. What you can find easily is a chip which takes a full composite video signal and outputs separate sync signals. Those chips can be directly used also with composite sync signal because it is just like a composite video signal without picture and has a little bith higher signal level. You can find a good list of such chips and links to their datasheets (which include example circuits) at http://www.epanorma.net/videochips.html.

I have used the following circuit (based on example from datasheet) for separating composite sync signal for monitors which need different kind of sync than what your source gives. The circuit is based on very popular LM1881 sync separation IC.



When building this circuit remeber to connect the grounds of the signal input and output connectors to the signal ground (little triangle connected to LM1881 IC pin 4). Good ground connection is connect thei circuit to the sync signal ground on the connector. Connect also +5V power supply ground to this signal ground.

By adding a little bit more electronics it is possible to make a real HSYNC iput by wisely combining composite sync and VSYNC outputs from LM1881 using the following circuit which consits of two logig gates (one AND one one NAND):

my tv worked with the scart rgb out on the TVator when hook up to the tvs 15 pin vga input.

if scart is 15 khz then the neo should work?

acem77 said:

my tv worked with the scart rgb out on the TVator when hook up to the tvs 15 pin vga input.

if scart is 15 khz then the neo should work?

Click to expand...

Let's leave "scart" out of this discussion since it's just the name of a socket (which is not found on your stuff btw) and not a signal.

I guess you're referring to this part of your first post:

acem77 said:

i wanted to test my vga port on the high def tv to see if it would support the rgb signal from the consoles.
for the hell of it i hooked up my pc to the TVator II and the 15pin scart rgb port from that to my samsung hi def sets vga port.
to my suprise the picture came in!
the test seem to show that i could hook up my games system rgb to the vga port with no problem.

Click to expand...

It's not surprising at all that you managed to display the picture from your PC on your TV through the TVator since that's precisely what it's supposed to do: convert a hi-res RGB signal (VGA) into a low-res one acceptable by a TV. The point is that the Neo Geo is NOT hi-res RGB like a PC but low-res RGB with a horizontal frequency scan of (about) 15KHz (and the same holds for the Genesis, SNES, Saturn, PSX, etc.). The TVator only accepts inputs from devices that have a horizontal frequency of 24KHz or higher so it's useless for your purpose...

Let me clarify one point, since the manual you linked is kinda contradictory. It says:

"Output signal: Composite video, S-video, Computer monitor
(PC, MAC or NEC) pass-thru output"

This would mean that it converts a hi-res RGB signal into a low-res ntsc (i.e. not RGB) one (composite or s-video) or it just serves as a pass-thru without converting the signal (i.e. from PC to PC). But if the 15 pin socket for hooking it up to a scart TV is actually a low-res RGB output then you'd be right. Only i find it odd that it doesn't mention it among the possible outputs.
Well just go ahead and try either by splitting the composite sync (from the Neo) or by connecting it to the horizontal sync pin alone (which should also work as a composite sync pin).

the out put of the scart 15 pin is lower res. the text is unreadable when using it.
and it works on my tvs vga input. wich works great with video straight from my pc and is very readable.
dont all scart tvs use the same refresh rate? is so is it 15khz?
and if thats a yes then i may be close to what i want.
as Dreamcazmans tv lets him hook up his neo geo to his hd tv with a simple mod.


i have a lm1881n chip and the caps and resistors. but i am not sure where to tie the grounds.

Don't use an external PSU for supplying the LM1881. The neo Geo outputs 5v from pin 4, use that:



However, don't take it for granted that pin 7 of the Neo A/V port is sync: on some later revision boards (NEO AES3-6 and probably also NEO AES3-5) pin 3 and pin 7 are both composite video and there's no sync pin on the A/V port. I mention this fact here. If your neo is of this type, then you have to either mod it internally and bring the sync to the A/V port (which I recommend) or strip the composite sync from composite video and then split the composite sync into Hsync and Vsync.

i am going to use a selector box i had for a rgb to svideo converter board i use from massystem. i have my neo-geo, genesis, super grafx and duo hooked to it.
i wanted to use just one lm1881n chip on the output so every system can use it.
how would i use the power supply then? do i have to use the 5v from each system?.... if can how do i do all the grounds?

for a test i wired everything like you showed and it worked!!!!!


too cool
look close at the pic about 2x there are some faint vertical lines?
but i wont complain

now how to get the other systems hooked up..??? see if they all have a 5 volt out put.

Cool!

As for the vertical lines, that's a known problem that affects many AES systems (esp. high serials). it can be fixed with a mod. That's in fact what Dreamcazman did (see the link I posted above).

And yes, practically all consoles have a 5v pin on their A/V ports.

Cool, good stuff Acem77. Glad to hear you got it working. Sorry I hadn't returned your PM, I was away for the last 2 days.

And I would advise you do the RGB mod (if you haven't already). Check out the link MKL posted. He was very helpful when I was doing my Neo.

ok i got it to work with my neo geo and turbo duo.
they all are diffrent how they work. the neo geo i have to get the 5v from pin 7
that should be the composite sync. i traced it back and it only gos to a few caps..
i pulled the c synce from the pcb and brought it to the composite video pin 3
and added a switch so i can select composite or rgb video(c sync).
only odd thing is my tv takes a long time to sync in the video but once done it stays till i turn it off.

the turbo duo i had to tie the composite video and the c sync together to get a sharp noise free picture. but my tv sycns in right away unlike the neogeo. colors are a bit dark but thats is a given for duos.

my genesis is being a pain in the ass. i get a signal not supported message :P
i tried a lot of diff ways to hook it up mixing what i found out about the other 2 systems.

all of these systems worked great on my rgb to svideo board. you would think it would be easy to get all the systems going.

i tried to do the clean rgb mod from the link. i still got the lines. if you look close at my 1st pic you can see them. i only cut the traces from the 3 resistors and the caps.. i did not want to remove so many of the components. seem too massive to do to the neo.. maybe i need to cut more or just need to remove every thing. for the perfect video.

do you think adding some 220uF caps in line with the duos rgb signal will brighten the pic up?

turbo duo

acem77 said:

only odd thing is my tv takes a long time to sync in the video but once done it stays till i turn it off.

Click to expand...

Every now and then, my TV's picture rolls for about 1-2 seconds and then syncs when I change inputs to the Neo (if the Neo is already on)

maybe this will help the video.
maybe something in the tvs service menu will help. i have been trying a few things
samsung service menu
simply turn your system off, then use the remote and press the following buttons with about .5 to .75 seconds delay between presses: MUTE-1-8-2-POWER