How to use SCART for our hobby

[LeedsFan]

Yes, if the cable is good then It should work on the Samsung, assuming that you have the TV in the right video mode etc ... although the cable itself should auto-select most of this.

If you like, I can make a cable for you for a fair price + shipping. The cable would be fully tested with multiple SCART TVs before leaving my hands. If for some wierd reason it doesn't work for your equipment, you can return it to me for full refund (less shipping) within a reasonable period. However, I have never had an unhappy customer.

Your VGA-SCART cable would have a molex plug for 5v & 12v input from PC, and look something like this:

OK I might just take you up on that offer. I'm in London for the weekend and I'm gonna have another go at making this cable when I get home. Got a new soldering iron as my other one was too big really for the small pins. I will let you know how it goes when I get back. 

[Zebidee]

No worries, PM me when you're ready.

For reference, when makling this cable I generally don't use a soldering iron (except for the 100ohm resistor bit). I usually use 2mm female brass connectors and just slip them over the male blades, as shown in the attached pic.  Use heat shrink tubing or tape to insulate the female ends. Heck of a lot easier than trying to use a soldering iron, and a lot more flexible as you can change things around or even disconnect the pins if you have to (for example, one sometimes forget to put the SCART end's plastic collar on before wiring pins up - it is much easier to deal with if you can just pull the connectors off with pliers and then slip the collar on).

If you do this no-soldering (almost) method, make sure to buy the SCART header with the almost flat blade (male) connectors (there are two kinds).

[Kman-Sweden]

So how 'bout "true" RGB to Scart?

From a real arcade PCB you can get
R
G
B
VidSync
VidGND

+5V
+12V
GND

Should I use the VidGND as R-, B-, G-return? and GND as GND (eg pin21)?

[Zebidee]

I have successfully mounted SCART TVs & presentation monitors as arcade monitors with JAMMA inputs. Check earlier in this thread.

If it was me, I wouldn't get too hung up about SCART pin 21 - it is only the shield ground. Most arcade monitor inputs don't have any shield, so cab wiring won't accomodate for it. If desired, you could hook the shield pin to either VidGND or the power GND, but vidGND will be easier unless you are running power signals in anyway.

I recommend that you put 75 ohm resistors on the R-G-B inputs, as JAMMA PCB (& JPACs) put out these signals at levels too high for TVs. You will need the resistors to bring down signal voltage level, otherwise the TV image will be way too 'bright' and would likely cause screen or other component damage in the long run. 75 ohm (or 68ohm is close enough) should be right on the money for this, but if your TV is unique then maybe you could vary the values slightly (e.g. down to 47ohm, or up to 100 ohm)

You don't need any resistors on the SYNC input - that should be OK.

Some PCBs might put out separate H & V syncs, rather than composite (more likely w/ older PCBs). This could be a problem if one of the syncs is not negative, because you can't easily combine +'ve & -'ve syncs without a little bit of conversion circuitry.

There would be no problem with tapping into the 5v & 12v for RGB & AV switch9ing signals. However, consider that you may be able to get away with just making a little wire bridge to short between SCART 20 and SCART 16 to get RGB mode on your TV.

I'm about to wire a Grundig TV into a JAMMA arcade cab. I'll post a pic after it's done.

[Kman-Sweden]

Cool.. So VidGND to all the 4 returns, 75 Ohm resistors on the R, G & B.
Sync to sync. Sync to 16 might be enough for AV-switching..

I'll be waiting for the pics..

BTW I'm building a Supergun for Jamma and NeoGeo MVS... I'll post here if you like, when I get it working..

[orchidius]

Hi there,

At long last I started working on my own cab yesterday, starting with this cable (I live in Europe and have SCART TV's at hand). Here's what I did chronologically:

*Got a SCART cable and a VGA cable
*Cut off one side of the SCART cable and one VGA plug from the VGA cable
*Desoldered all the wire leftovers from the VGA cable
*Cursed
*Went to a friend with a better soldering iron, mine was too big
*Cut off/desoldered all unnecessairy wires from the SCART cable
*Cursed again
*Resoldered the wire I mistakingly cut off back into place
*Soldered all the wires in the right place (including MOLEX plug and resistor) --> I used the wires from the old SCART cable
*Made sure that no wires were short circuiting and sealed everything with hot glue (figured this would be easiest to isolate all wires)
*Measured all contacts with a multimeter (they were all good)

I then installed the soft15khz program on my computer and connected my VGA graph card with my SCART (50khz) tv. Rebooted the pc and all I got as an image was a combination of following 2 videos:



and



I also tried running the soft15khz program at 25khz, 31khz and a combination of 15/25/31khz. All options gave me the same problem.

Any ideas? :s

[Zebidee]

Your first video looks like you have tried to boot into something other than 640x480, like 1024x768.

Bear in mind that Soft15khz has variable performance when used with onboard chipsets (e.g. "Intel 945")  - it might work with some, but not with others.

Your second video looks like you have something wrong with your sync wires or vertical hold.

The difficulty is that there are too many unknowns with your setup and hardware. You might find your solution in the Soft15khz thread. Or you might solve the problem by switching the TV  inot the right AV mode. Or your cable might be wired wrong. You want some controlled variables in order to do trouble shooting - e.g. ArcadeVGA card for video output, pre-tested VGA-SCART cable, pre-tested TV etc.

[orchidius]

So you're saying that a one-time builder or a first-time builder can't use this setup if he/she doesn't get it right from the first time? :s

Here are some specs that might help:

TV: Sony Trinitron KV-20WS1B
Graph card: ASUS EAX600PRO - running at 15khz with Soft15khz
resolution: 640x480
VGA-SCART cable: below the last build I tried (also tried the original build mentioned in post 1, both builds of course WITH molex plug)

http://img580.imageshack.us/content_round.php?page=done&l=img580/4853/naamloosd.jpg&via=mupload

[Zebidee]

So you're saying that a one-time builder or a first-time builder can't use this setup if he/she doesn't get it right from the first time? :s

Heh, I never said the "can't" word. But to solve your problems you need to work out what you know and what you don't know.

Let's assume that your TV works properly with RGB SCART.

You need to ask yourself:
- Is Soft15khz working properly with my video card & selected drivers?
- Is your cable built properly, without errors?

Most importantly, you need to work out:
- What video card have I got?
- What is my Youtube username?
- Who am I?

What I'm getting at with the last three questions is that your posted videos are from different users, with very different setups. One claims to use a laptop with inbuilt graphics, the other one claims to uses a NVIDIA 8600GS video card. However, in your post, you claim to be using an ASUS EAX600PRO. So ......... I don't really know  what is going on here.

[orchidius]

I have multiple personalities

No really, I didn't film my own tv since the only camera that I own is really my cellphone camera... But I figured that here hàd to be people out there with the same issues who did make a video. And I was right . So the above vids are just vids from random people that I found that are/were having roughly the same issues  as I am.

As I noted before, the card I am using is most definitely an Asus EAX600PRO. It has all drivers installed (catalyst 6.5) and Soft15Khz running properly.

The issue is also not the TV itself as I tried multiple tv's with the same results today.

The issue is also not in the cable. I measured àll connections multiple time and they are all good.

I've had some valuable tips from Sailorsat which I'm gonna try tomorrow:

1) Try it at 640x240 resolution
2) Use the DVI port instead of the VGA port

Anything else I could possibly try?

[Zebidee]

Your video card is an ATI chipset right? Try using an older version of the control panel software (e.g. Catalyst 6.5).

I'd be wary about assuming the cable is all good. What voltage is present at SCART pin 16? Is the sync right at pin 20? Is the sync grounded? You tried multiple TVs which is good. However, even if your Soft15khz is buggy/wrong, many TVs will still give you a split screen in 31khz modes.

[orchidius]

ATI chipset, correct. The control panel software is Catalyst 6.5 as mentioned below

The pc is confirmed to be running at 15khz. I also tried multiple regular computer CRT's and they all gave me the "signal out of range" message, which would not be the case if it was in fact still running at 31khz

The cable build I'm using currently is the following, exactly as the picture below:

http://img580.imageshack.us/i/naamloosd.jpg/

I'm not sure on the voltage at pin 16, but I did the molex plug/100ohm resistor thing as mentioned in post 1 (exactly the same as the pic in post 1). I'll measure it out later today.

About the sync wires: as in the pic above I joined the two brown ones at SCART pin 20 and made them go to VGA pin 13 and 14 respectively. No extra ground is present...

Thank you for the help and the patience you have with me, I really appreciate it.

[Zebidee]

I think that your problem is most likely sync related.

I've never really liked that wiring diagram - pretty as it is.

The problem with that diagram is that sync ground (VGA 10) is not connected to anything. What is your VGA 10 connected to? Can you get connectivity between VGA 10 & your SCART ground? VGA 5 (another ground, H-sync I believe) is similarly not connected to anything. So maybe you should start again?

From the top:
- connect RGB (VGA 1,2,3 to SCART 15, 11, 7)
- connect H+V sync (VGA 13+14 to SCART 20)
- connect Switching signal to SCART 16 (5v from VGA 9 or MOLEX +100ohm gives 2v, or bridge SCART 20 -> 16)

After that:
- cut off any wires from VGA 4, 11, 12, 15. These are monitor ID, worse than useless to us. Don't get them mixed up with your grounds.
- cut off wire from VGA 9 (5v) if it is present and you haven't used it.
- gather whatever is left, they are the grounds (VGA 5, 6, 7, 8, 10). Twist them together and connect them to a suitable SCART ground pin (e.g. I prefer SCART 17, but any should do)
- Connect VGA shield ground to SCART shield ground (SCART 21)

PS, I always refer to these pinouts with my pin numbering format:
SCART pinout:  http://pinouts.ru/Home/Scart_pinout.shtml
VGA pinout:      http://pinouts.ru/Video/VGA15_pinout.shtml

[orchidius]

IT WORKED, IT WORKED!! I got an image out of the bloody thing! Wasn't getting my hopes up, because during the entire bootup the tv was still out of sync, but once it displayed the XP desktop, it was "all good" (well, not àll good, but I could live with it)! Is that normal (just being curious)?

One tiny issue I'm still having though is the positioning of the screen. I seem to lose about 3/4th of the taskbar on the bottom, and when I start up HS, It's also not centered. Is that tv-related, or anything I can do 'bout it?

Thanks a bunch!

[SailorSat]

That seems to be normal.

The BIOS/Bootup Screens are still output in 31kHz so your TV can't sync them correctly.

As soon as Windows kicks in the output is in 15kHz and your TV can sync it perfectly.

As for the "missing screen", yes that is normal. It is called overscan.
The  "tv standard" is about 80% to 90% visible.
TV signals contain binary data on the first lines, like 4/3 vs. 16/9 switching, clock, teletext etc.
Some games might get cut off but usually that shouldn't be a big deal.

Arcade monitors usually show everything.

You might fool around in your TVs service mode (if it has an OSD) or inside the TV, but I wouldn't do that except you want to put the TV in a cab.

[orchidius]

This tv is just a test tv, so I won't be fiddling with that one. I'm getting another one shortly to put in my first cab, so I'll look into it when I get the "new" tv.

Thanks for all the help and great input, I wouldn't have gotten here without you guys!

[Zebidee]

What made the cable work in the end? Was it sync ground, something else?

[orchidius]

Honestly, I don't know... I'm guessing sync ground.

I just started all over again. Cut off both ends of the wire, desoldered both VGA and SCART piece, stripped all wires again, the whole shabang.

Most of it was the same as last attempt though, the added sync ground was all that was really different.

[Atomicburner]

Hello to all.
Im Portuguese from Europe.
Sorry my bad English.
I have a strange problem with my vga-scart cable/TV, and I'm in need of help.
I´ve got a Sony KV-X2521D and an AVGA.
I´ve got this combination:

VGA      SCART
1   ->   15
2   ->   11
3   ->   7
6   ->   17
7   ->   17
8   ->   17
10   ->   17
13   ->   20
14   ->   16 - 20
vga ground -> 17

PC Power         SCART
+12v   ->         8
+5v   ->   100Ohms   ->   16
0v   ->            18

In my TV from kitchen it works fine, but in Sony it´s always rolling.( SONY its in my cabinet)
I´ve made 10 cables, now i´m frustrated.
I can put video on youtube for u all to see.
Anyone can help me, please.
Thanx to all.
 

[Zebidee]

VGA 13+14 => SCART 20

VGA 5 (Hsync Ground) +> SCART 17

[Atomicburner]

Thank you Zebidee, but it continues the same, picture is rolling, and i dont have h.sync and v.sync in the TV.
I tried this especifations you gave me with the 5volt + resistor and 12 volt, and without them.
 

I bought this TV for my arcade and now i´ve gotta sell it...
So now i´ve got this

VGA      SCART
1   ->   15
2   ->   11
3   ->   7
5   ->   17
6   ->   17
7   ->   17
8   ->   17
10   ->   17
13 & 14  ->   20 goes to 16
vga ground -> 17

PC Power         SCART
+12v   ->         8
+5v   ->   100Ohms   ->   16
0v   ->            18

I think this TV is the first one to cheat the cable.
Cheers
Rui

[SailorSat]

I would NOT connect the syncs AND the power supply to scart pin 16.
power to 16 is ok, connect the syncs to 20 only

[Atomicburner]

Thanx for the info Sailorsat, but it get worst. Now i only can see white dots and rolling picture...with or without the molex, sometimes gets blank and then goes black...i think in my case i must have 13 & 14 together to scart 20 and then from scart 20 to 16.

Any ideas..?
 
cheers

[Zebidee]

Sailorsat is right - use 5v + 100ohms -> SCART 16 (best, should work for [almost] all TVs)
OR
bridge SCART 20 -> 16 (simpler, works with many TVs)

But not both as this is asking for trouble.

You mentioned that your cable works with a different TV, which suggests that the problem is with your Sony TV.

- Your Sony does not have a v-sync adjust control anywhere? Are you sure?
- What video mode are you in- 640x480? If so, try 640x240 or something similar ... some Sony CGA professional monitors don't support interlacing! But all their TVs should be OK.
- Your Sony might not accept RGB via SCART (i.e. only composite through pin 20) - but this is unlikely. I've only seen this once before, and that was with a very cheap & nasty brand of TV (Goldstar - this company has since morphed into Korea's LG)
- Try disconnecting the 12v power supply - you might be forcing the Sony into the wrong A/V mode by accident. You can always select A/V mode manually.
- Make sure that everything is connected & insulated properly - i.e. no shorts
- Make sure that you can feed a normal video signal into your Sony (e.g. TV, DVD), in case there is some deeper problem with it.

[Atomicburner]

Hello Zebedee
Sry for the long post.

(You mentioned that your cable works with a different TV, which suggests that the problem is with your Sony TV.)
I think the same.

(- Your Sony does not have a v-sync adjust control anywhere? Are you sure?)
I´ve got this adjustments as you can see in picture above, then i´ve got 2 others in the middle of the board of TV witch i already touched and nothing
happened.

(- What video mode are you in- 640x480? If so, try 640x240 or something similar ... some Sony CGA professional monitors don't support interlacing! But all their TVs should be OK.)
I´m using Arcade VGA from Ultimarc, and in the other TV the image is OK with very bright colors, but in Sony i can see the bios but the picture is always rolling.

(- Your Sony might not accept RGB via SCART (i.e. only composite through pin 20) - but this is unlikely. I've only seen this once before, and that was with a very cheap & nasty brand of TV (Goldstar - this company has since morphed into Korea's LG))
Yes it does, you can see in picture above.

(- Try disconnecting the 12v power supply - you might be forcing the Sony into the wrong A/V mode by accident. You can always select A/V mode manually.)
Sony is going to the right A/V1, and if i disconnect the 12 power supply i can always select A/V mode manually as you said, and the picture
doesn´t modify.

(- Make sure that everything is connected & insulated properly - i.e. no shorts)
I always check if there is a short circuit with the multimeter in the pins of A/V.

(- Make sure that you can feed a normal video signal into your Sony (e.g. TV, DVD), in case there is some deeper problem with it.)
If i connect a DVD to the Sony, Bam awesome , it runs gorgeous.

By the way, i tried only to connect vga 13 & 14 to scart 16 (with no connection to scart 20) its rolling picture
but if i connect vga 13 & 14 to scart 20 (with no connection to scart 16) it gives me black picture with white dots.

I just dont know what to do.
Maybe this TV only syncs if audio connected? any ideas?
Zebidee i know you made cables, im going to PM you, ok?
Cheers

[Atomicburner]

One picture gave me error while posting, lets see if this time the picture keeps posted.
Cheers.

[SailorSat]

Hm... Resumé

Sync to 20 only - only black dots -> TV in composite mode
Sync to 16 only - rolling picture -> TV in RGB mode but no sync line connected.

--

Try this... Step-by-Step


Step 1 (Black Screen):
VGA 1 to SCART 15 = RED Signal
VGA 6 to SCART 13 = RED Ground


You should see a black screen.

--

Step 2a (Switch to RGB - VGA only):
VGA 9 to Resistor ~68-100 Ohms to SCART 16 = BLANK Signal
VGA 5 to SCART 18 = BLANK Ground

Step 2b (Switch to RGB - PC Molex):
+5V to Resistor ~68-100 Ohms to SCART 16 = BLANK Signal
GND to SCART 18 = BLANK Ground
+12V to SCART 8 = SWITCH Signal


Depending on which way you choose, you manually need to select AV(1).
The screen should turn Red.

--

Step 3 (Add Sync):
VGA 13+14 to SCART 20 = SYNC Signal
VGA 10 to SCART 17 = SYNC Ground

The screen should becomed synched.

--

Step 4 (Other colors):
VGA 2 to SCART 11 = GREEN Signal
VGA 7 to SCART 9 = GREEN Ground

VGA 3 to SCART 7 = BLUE Signal
VGA 8 to SCART 5 = BLUE Ground


The screen should be fine now.

--

Step 5 (Sound!)
Yes well...
Get a 3,5mm Stereo connector

Inner Pin to SCART 4 = Ground
Middle Pin to SCART 6 = Audio Right
Outer Pin to SCART 2 = Audio Left

[Atomicburner]

Hello Sailorsat, thanx, but yet, it was not this time...

(Step 1 (Black Screen): VGA 1 to SCART 15 = RED Signal, VGA 6 to SCART 13 = RED Ground, You should see a black screen.)
Right.

(Step 2a or step2b : , Depending on which way you choose, you manually need to select AV(1). The screen should turn Red.)
Wrong, the screen stays black.

(Step 3 (Add Sync): VGA 13+14 to SCART 20 = SYNC Signal, VGA 10 to SCART 17 = SYNC Ground, The screen should becomed synched.)
Wrong, it appear a black screen with white dots, and its desynchronized.
 

Thanx for the info.
cheers

[Zebidee]

Seems that your Sony is in composite mode.

Something tells me that your RGB switching signal is borked. Can you try using the 5v + 100ohm resistor -> SCART 16 again? Leave the casing off your SCART header and use your multimeter to double-check the voltage while in-circuit (ie plugged in) & everything turned on. The voltage should be close to 2v.

If it is ~2v, then try connecting the 5v *without* the resistor - maybe the higher voltage will trigger RGB mode. I suggest this because you seem to get a rolling RGB picture when you connect the sync to SCART 16. Your sync from an ArcadeVGA card is likely at around 4.5-5v.

if NOT (e.g. if it is still 5v), and you are sure there is no other problem, then it suggests that your Sony is not 75ohm terminated like it should be. Try this:

Add another resistor (75 ohm is probably perfect, but one of your 100ohm resistors should do) to the SCART 16 pin or wire, and connect the other end of the resistor to any ground pin (SCART 18 will do, but any is OK - it shouldn't matter much). This will then create a simple VOLTAGE DIVIDER, which would reduce the voltage input to approximately half of what it was before (~2.5v).

Here is the formula at play here, using 100ohm to ground:

Voutput = Vinput * (Rground / (Rinput + Rground))
Voutput = 5v * (100 / (100+100)) = 5v * 1/2
Vouput = 2.5v

To reduce the voltage further you could either add more resistance (ie more or 'larger' resistors) to the input, or use a lower-rated resistor (e.g. 75ohm) to the grounded resistor.

This latter case (using 75 ohm to ground) would then give you:

Voutput = 5v * (75 / (100 + 75))
Voutput = 2.14v

[Atomicburner]

Hello Zebedee
I´ve got one problem here, the resistors that i have, are damaged, because i the voltage after the resistor is 5.06, always.
So, i always tested this with 5v direct to Scart 16, hope not to damaged the TV, im going to connect a DVD to see.
Only on monday i can buy some resistors, on monday i will give you news.. thanx for the help..

[Zebidee]

In that case you have three possibilities:

a) tested the voltage out-of-circuit (i.e. without the SCART plugged in your voltage readings will be wrong - the DMM will read 5v!);
b) your resistors are faulty - test your resistors separately, just use your multimeter on ohms setting; or
c) your Sony TV is not '75ohm terminated'.

In the last case (which seems possible as your other TV worked), try making a voltage divider like I described in my last post. This will give your TV the '75 ohm termination' that it needs, and you will get  approx. 2.0 - 2.5v at SCART 16 to trigger RGB mode properly.

[Zebidee]

Oh, I was having a close look at that pic you posted earlier. have you tried adjusting the pot in the top left corner marked "V.CENT"?

[Zebidee]

Something else I noticed in your pic - there is a connector next to your flyback transformer that looks like it is about to fall off!

[Atomicburner]

Hello Zebidee

(In that case you have three possibilities:
a) tested the voltage out-of-circuit (i.e. without the SCART plugged in your voltage readings will be wrong - the DMM will read 5v!);
b) your resistors are faulty - test your resistors separately, just use your multimeter on ohms setting; or
c) your Sony TV is not '75ohm terminated'.
In the last case (which seems possible as your other TV worked), try making a voltage divider like I described in my last post. This will give your TV the '75 ohm termination' that it needs, and you will get  approx. 2.0 - 2.5v at SCART 16 to trigger RGB mode properly.)
- In this case it was the a, after all my resistors are fine, i measure them as you said, i did try the c, and the screen keeps black with white dots and roll less.

(Oh, I was having a close look at that pic you posted earlier. have you tried adjusting the pot in the top left corner marked "V.CENT"?)
- Yes, i had, and its to picture grow in vertical.

(Something else I noticed in your pic - there is a connector next to your flyback transformer that looks like it is about to fall off!)
-Thanx for the info, its already in place.

-I can only see something in screen if i join vga 13 or vga 14 to scart 16 or both 13 & 14 to scart 16, if i join 13 & 14 to scart 20, the screen appears black with white dots rolling.

Now, im going to buy some 75ohm resistor, do the test again, and then i say the results.
Thanks Zebedee and Sailorsat for the help u have giving me.
cheers.

[Atomicburner]

Hello ...

I already tested with the new 75 ohms resistors...
The image is more stabilized, its less rolling picture. I think if i had some vertycal sync in my tv, now i could adjust... but i dont have...
Zebidee, i tried as you said with 2 resistors, but the 75 ohms, because if i put the 100 resistor i have 0,014 v reading in multimeter.
Im not electrician, but i think im reading well the multimeter.
I sent u a PM Zebidee.
Cheers..
Rui
 

[Atomicburner]

Forget to post this:

If I connect 13 & 14 to Scart 20 and molex with 75 ohm to Scart 16, i can see image more stabilized.

Cheers.
Rui

[Zebidee]

If I connect 13 & 14 to Scart 20 and molex with 75 ohm to Scart 16, i can see image more stabilized.

Does that mean you have solved the problem, or is the picture still rolling?

[Atomicburner]

Hello
The picture still rolling, but less rolling.
Cheers

[Zebidee]

Crikey, are you 100% sure that both your VGA 13+14 wires are hooked up & connected, all the way from the VGA snd to the SCART end?

All ground pins (VGA 5,6,7,8,10) grounded?

At the PC, check to make sure that your video driver is using both negative horz & negative vertical sync (i.e. not composite, not positive).

[wilch]

i'm having trouble with a newly soldered cable too, all i see is a black image. i have a radeon 9250 and a sony trinitron.
i'm going to try 'VGA 5 (Hsync Ground) +> SCART 17' as pin 5 is not connected to anything.
also i tried scart 16 to 20 so now i'll try with the molex.
i have vga 13+14 to scart 20, is this necessary using radeon 9250?

also note, when i connect my xbox rgb, the tv switches to AV1-RGB and the top left display shows 3 little dots representing RGB, when i switch to AV1 with the remote it doesn't show the dots so i guess i definatley need the molex power....

also, i use DVI to LCD as primary display and tried the tv via the vga port. when i set soft-15hz mode, can i install it for the secondary display only while using the LCD as normal and have dual displays?

thanks