How to use SCART for our hobby

[joecontra]

Alright!

What schematic did U use and what cable has been yours built of?
Maybe it's up to the TV set, maybe it's very old (just guessing).

Does the TV set give better colors in case of signal from other RGB source?

Regards,
joecontra

[Zebidee]

Resistors on the RGB lines would only make the colours less bright.

Sounds like an issue with your TV being a bit old and tired, so check it with another input source.

A rather less likely possibility is that your video card RGB outputs are relatively low. In that case you could try a video amplifier (ultimate sells them at a reasonable price), but a fair bit of hassle involved with hooking it up. Better to test with another TV first.

Cheers, Zeb

[arcadeswede]

Must be the videocard then because I've tested my CRT with another RGB source and it worked. Bummer! Thx for the answer guys!

[Rigby]

well, PC VGA ports typically only output 1V of signal, some monitors like 5V and don't amplify it themselves.  I don't know what voltage SCART expects, but given that it's not a protocol or signalling standard, it seems that it would depend on the TV you're hooking up to.  Amp it up to 5V and I think you'll have an amazing picture.

[arcadeswede]

You mean amping the pins red, blue and green?
How? Any tips?

[Zebidee]

well, PC VGA ports typically only output 1V of signal, some monitors like 5V and don't amplify it themselves.  I don't know what voltage SCART expects, but given that it's not a protocol or signalling standard, it seems that it would depend on the TV you're hooking up to.  Amp it up to 5V and I think you'll have an amazing picture.

Rigby, while what you say about arcade monitors requiring higher voltage on RGB is true, the RGB TTL standard for TVs is only 1v. Should be no need to amplify the signal from a video card to a TV. I've done VGA/SCART to literally dozens of TVs and never seen an exception to this.

If one does need a video amp, Ultimarc sell the at reasonable prices. But it is likely not necessary. Better to check with another TV and another video input source first.

You could use a multimeter to check the voltage on the RGB signals but this is tricky as is must be done while the system is operating and requires access to exposed RGB signal wires while everything is turned on, in-circuit and working. I did this before with a JPAC from Ultimarc (which has an on-board video amp) hooked up to a TV and was surprised to find only 2-3v on RGB. In this case I has the opposite problem - the voltage was too high for the TTL TV standard 1v and the picture was "blooming" as the colours were too bright.

So I suggest testing the RGB voltage levels while everything is in circuit and turned on. Be aware that the RGB voltages will vary depending upon what is happening with the video signal, but should peak at around 1v.

[arcadeswede]

Ok! No problem, I can check that with a multimeter. In my case, I should have a low voltage value, right? Under 1V maybe?
That's may be the reason why my colors are weak.

If the RGB signals ends up being at 1V I don't know what to do next.

FYI: I have a 12V source connected to the SCART plug to make my CRT TV select the SCART input when turned on.
Is this something I could use for amping the RGB signals if they're low?

I also don't have any resistors och anything in my SCART plug. Only wires connected to pins. Good or bad? Is there any resistors you really should have that I've missed?

[NightSprinter]

Bit of a curiosity: I know there were some RCA Dimensia sets that had an "EIA MULTIPORT" socket, and earlier revisions only supported TTL signals.  What about the port on later models that also had an s-video socket?  I am curious about what type of RGB (if at all) was supported by the later CTC140 chassis.

[Locke141]

Figured out I can buy SCART CRT TV's her in Tanzania for around $40 US for a 19 inch, with out haggling. As an American this is a rare opportunity. As a plus, we get a shipment back to the US when we move home as part of my wife benefits.

I'm tempted to pick up a larger TV as well as it is unlikely I'll have the opportunity to buy a SCART TV once I'm back in the states. Now my questions is what should I be aware of when buying one?   

[Paradroid]

Now my questions is what should I be aware of when buying one?

Nothing in particular. As long as the TV supports RGB input via SCART (I have seen some that only accept S-Video via SCART) and also NTSC and PAL (I have only seen one PAL only SCART TV out of the 100+ I have come across in my travels) so you've got the 50 to 60 Hz range covered.

I guess the other consideration is whether you want picture adjustments via a Service Menu or internal trimpots. Both have their pros and cons.

Tanzania... I never knew they had SCART there! My 3 months in Berlin where heaven for SCART hunting but I didn't have enough money left to ship any back home...

Good luck!

[adder]

Now my questions is what should I be aware of when buying one?

try to get one which has the original remote control included, as you may need to use it to get into the service menu to make adjustments (or try to ensure the remote control you require is available on ebay)
try to get a decent brand tv:  eg.  sony, JVC and panasonic are all excellent brands
getting a decent/well known brand tv means you are more likely to be able to find its service manual online, which will detail things like the service menu (how to access it) and the possible adjustments you can make (eg. horizontal size/position, vertical size/position, etc)
and if possible try to avoid a tv on its 'last legs' .. of course that's not always easy though, as many old school CRT TV's are now around 20 years old

[Locke141]

Tanzania... I never knew they had SCART there! My 3 months in Berlin where heaven for SCART hunting but I didn't have enough money left to ship any back home...

Good luck!

Yea SCART is not an official standard here but so many TV have be brought over by expats and I would imagine that the worlds back stock of crt TV's got shipped here. I don't think there is much hope of finding the original remote. How about a universal replacement remote?

and if possible try to avoid a tv on its 'last legs' .. of course that's not always easy though, as many old school CRT TV's are now around 20 years old

Believe it or not, you can still buy new CRT TV's here. They don't have SCART and they don't always have the best pic or cooler but there are apparently still manufacturers.   

[Locke141]

I went and looked at a few TV's today. Some of the 14 inch ones were in really good shape. All the 21 inch ones with SCART at this shop were all flat glass and did not have the best images. 

I took down the info on one seem to have a particularly good image a Philips 14pt6107/05d. I found the manual but it does not say any thing about the service menu or wether or not it supports RGB over SCART. I can get to the Picture settings with out a remote. What should I do? Is there a web site that will tell me how to get in to the service menu?

Edit:Found this I'll test it tomarrow.

Service Menu Code For Philips TV:

There are many codes available for accessing service menu in various Philips TV models. You can try following codes one by one until you get access to service menu:

0 + 6 + 2 + 5 + 9 + 6 + Menu/Info/Status
0 + 6 + 2 + 5 + 9 + 7 + Menu/Info/Status
0 + 6 + 1 + 5 + 9 + 6 + Menu
0 + 6 + 1 + 5 + 9 + 7 + Menu
1 + 6 + 2 + 5 + 9 + 6 + Menu/Status
1 + 2 + 3 + 6 + 5 + 4

If you have a different brand TV set such as Panasonic, Toshiba, Videocon, Onida, Sansui, Sharp, Akai, etc, feel free to ask us for the secret code to access its service menu...

 Also they have replacement remote that are specific to each brand.
I'm thinking of making a VGA to SCART cable and just testing each TV. 

http://www.p4c.philips.com/cgi-bin/dcbint/cpindex.pl?slg=en&scy=gb&ctn=14PT6107/05

It seems that most of the Philips CRT's here have SCART.

[Locke141]

I'm a little confused. Is the return for each color the shielding around that color? I tried to test with my multimeter but all shielding goes to ground so its not posable to confirm with a multimeter.

Also in my VGA cable Red signal is a red wire, Blue signal is a blue wire, Green signal is white, and one sync is green the other is white. That was needlessly. confusion.   

[sqwirral]

Does anybody know what I've done wrong here?



This is a Jamma PCB going to the RGB scart input on my TV. The board output is fine when going into a scaler/line-doubler thing I've got. The TV is fine when plugging in any RGB game consoles. I get the same effect on another spare CRT too.

It's not really a black and white image, it's almost totally black with only the outlines of sprites etc visible, these pics were taken with brightness wacked up full.

The Jamma harness has a plug with R,G,B,GND,SYNC wires. Those are going to the appropriate pins on the scart plug, as shown in the OP. The only difference is I'm using one GND wire daisy chained to all the returns, instead of lots of seperate grounds... is this what's causing the problem? All the grounds are joined together on the board anyway so I don't see how it would make a difference.

I've added +5V to the blanking pin 16, this made no difference good or bad. I added a 100 Ohm resistor to this wire, still no change. I added 150 Ohm resistors to the RGB wires, obviously this doesn't help either. I haven't sent any voltage to pin 8 since I can just use the remote control to switch to the scart channel for now.

(My theory was if I can get this simple board working then I'd tackle the whole vga soft-15khz thing next...)

[sqwirral]

Some progress from the post above:



It's now working on my tiny spare CRT. I removed the resistors from the RGB wires, and removed the resistor from the blanking pin wire and just bridged it to the sync pin (as Zebidee suggests on page 1) instead of using the +5V from my PSU. Aside from some overscan on the right, the picture is absolutely perfect, even without those resistors the RGB isn't too bright.

Problem is, my main CRT is still showing exactly the same mostly-black screen as in the previous post. No difference. Any ideas?

Here are my wires from PCB to scart:
R -> pin 15
G -> pin 11
B -> pin 7
S -> pins 20, 16
GND -> pins 5, 9, 13, 18

[Zebidee]

sqwirral:

I suggest you try combining all your ground wires together ("daisy chain") and hook them up to pin 18. Although I guess that is what you had before.

We don't know if all those grounds (5,9,13 for RGB) are actually connected on that TV. Most commercial SCART cables I've pulled apart just combine the grounds. Ground on pin 18 should be good.

Keep in mind that you may need different SCART cables to accommodate different TVs, as not all SCART TVs are the same. For example, some TV's work better with (PSU +5v + resistor) to pin 16. Some work better if you just bridge 16 to 20. So I made both kinds of cables. You might be better off keeping your cable that works for your "spare" TV and making a new one for your "main" TV.

Regarding your RGB brightness and JAMMA: if you are connecting jamma boards, diffrerent PCBs may have quite different RGB output levels. So the nice picture you get with "Taito Cup Finals" might be different (e.g. colour too bright) with another JAMMA PCB! In such a situation resistors on RGB might help. Something to keep in mind as you try other boards.

[sqwirral]

Thanks for the reply Zeb.
I was waiting until I had some more meaningful info before posting again, but I appear to have got sidetracked onto other things so I'll just say thanks and attack this TV again in... probably about a year knowing me

[steocullen91]

I know this thread is old but I'm interested in doing this. I have a CRT and 2 other TV's here I have with SCART connectors. I have a spare VGA cable and a SCART lead. Can I just make it like page one or do I need resistors? The only resistors I have here at the minute are 33ohm.

[Dragon89o]

Informative thread. +1

[ckong]

 Never mind

[Zebidee]

I decided to update this thread slightly. I was just messaging a European member about VGA-SCART construction, so decided to post here as well, recycle the words

My own understanding of making these cables has evolved over the years. I've made dozens in my time, using different techniques. So I thought it worth posting some tips n tricks.

There are different ways to build these cables, no single way the best. The differences mostly come down to the sync and blanking.

Obviously you run your RGB into pins 15,11,7. Video grounds can all be joined together, any ground pin will do. Ground the 5v/12v to a different ground pin.

Sync goes to pin 20. VGA sync voltage (~4 - 5v) is too high for TVs (~0.3v - 1v), so you want to use a resistor (470R to 1K) on the sync input. You can:
- just twist the sync wires (VGA 13+14) together and run that wire through the resistor.
- Alternatively, you can just connect VGA 13 (H sync), via resistor, but then you must setup composite sync with CRTEMU/VMMaker or whatever you are using.
- Another alternative is to use a pair of Dupont connectors for the Vsync (pin 14) connection, so you can disconnect if running with composite sync out of CRTEMU.

I suggest using a single resistor on sync, rather than two resistors (one on each H+V lines). Using two resistors can cause signal reflection interference.

Twisting the wires together is simple, gets you "smushy" csync, which will probably work for most CRT TVs but not all. It is pretty good but not perfect, there may also be some visible artifacting from smushy sync, like a little zigzag at top of screen. Might not matter for many people. Different TVs show different things. Some TVs might lose csync every few seconds.

Csync output from CRTEMU is usually better than smushy sync. It comes out on VGA 13 (Hsync) only. However, if pin 14 (Vsync) is still connected then you may get some interference (the line voltage is able to "float", sometime causing false signals). So, best to remove Vsync connection completely if running with CRTEMU Csync.

For the blanking voltage, best to take input from PC via standard PSU MOLEX connector (with 4 pins). If your PC has only SATA then buy a SATA-MOLEX adapter (or make one ). You can get both 5v and 12v from MOLEX. You only need to connect one of the grounds.

Take the 5v via resistor (150-200R) to pin 16 for blanking. When connected to TV, which is 75 ohm terminated, this will divide the voltage, giving you ~1.5v - 2v blanking signal.

Optionally, you can also take the 12v directly to pin 8 to autoswitch the TV into AV mode. Only some TVs need this, many will stay in AV mode after powering off/on again. You may be able to control this via service menu. Also pretty easy to press the AV button on remote or front panel. However, it can be handy if you are mounting a TV inside a cab, and need the TV to autoswitch into AV mode when powering on.

I use female spade crimp connectors (2.8mm) + heat shrink tubing, which means less soldering. It works with both the "spade" and "bucket" pin-type SCART header designs. This really is the easy way to do it. Also means you can remove wires from pins as needed, like when you realise you've forgotten to put the locking ring on first!   

If using the female spade connector trick, you will need to break off the last pair of "wings" (that lock the wire down) for it to fit inside the SCART housing. Lightly rub down the broken end with a file or sandpaper to remove any sharp bits. You will also need to bend the necks a bit (match the angle of the SCART header).

 


 

[Dodonpachinko]

Hello everyone,

I'm trying to build a DVI-I to SCART cable and would really appreciate if people who have experience with VGA to SCART cables could tell me if it would work.

It's really hard to find informations on these cables for some reasons and like Zebidee said there not one single wiring method.

Given that the traditional DVI-I to VGA adapters are passive, it's technically possible to create a DVI-I to SCART cable.

I used this VGA to SCART schema for wiring: https://imgur.com/a/F23Ckeu

I used this table for pinout correspondance: https://pinoutguide.com/Video/dvi_to_vga_adapter_pinout.shtml

I've come up with two solutions, one with MOLEX(5V+12V) and one with USB-A(5V only):

MOLEX: https://imgur.com/a/04Au5UV

USB: https://imgur.com/a/2KFW92F

I'd really appreciate some feedbacks before i try to build it.

Thank you!

[Zebidee]

Both of those wiring schemas seem sound.

Some thoughts:

- Maybe easier to make a VGA-SCART cable and use that with a passive DVI-I to VGA adapter. This will give you more flexibility to use with other video cards.
- If still going DVI-I, it has 5v out on pin 14, and AFAIK this is standard for all. So you could use this for blanking instead of molex/USB? Ground is DVI pin 15.
- You probably won't need the 12v switching
- Run all your VGA RGB+sync grounds (5,6,7,8,10) together to one wire and a single SCART ground (choose whichever is convenient). For DVI-I end they're already joined.
- You could choose to run the blanking ground separately to SCART pin 18, though all these grounds are most probably joined at the TV end anyway (check it with your multimeter).
- You can combine the H+V syncs and then run that through a single resistor (470R to 1K). I've seen some people encountering signal reflection/interference when using multiple resistors, though this might only occur when they use different values for each.
- If you want to try composite sync (better than smushy) output from your PC/device, arrange it so you can easily disconnect the V sync wire (to avoid floating/ghost signals).

Unless it is important to you, leave the audio connections out to simplify. It is hard to fit everything into the SCART header/housing. Most TVs have separate audio inputs, and audio cables (3.5mm stereo to 2xRCA) are cheap to buy.

FYI Though they usually have two audio input jacks (often red/white), most TV speakers are wired for mono - the stereo inputs just get smashed together anyway. Makes sense when the speakers are only about 2-3 feet apart. Most TV speakers will also have considerable interference hum too, which isn't very obvious when watching video but more obvious when gaming. So, all things considered, you might choose to use some external speakers.

This all leaves you with only six wires to connect at the SCART end (R,G,B, H+V, switching, ground), seven if you run the switching ground separately.

[Dodonpachinko]

Thank you for your response and your experience, it's very helpful!

I want to try this because i only have DVI and SCART cables at the moment...

We don't really know how good the connections are on those passive DVI to VGA adapters. They're often cheaply made and can become a point of failure in the line.

I tried to make a new schema taking account of your recommendations: https://imgur.com/a/IDJlwso

The C5 pin on DVI is analog GND. It's connected to the shields of each RGB wires. I don't know if TV need these but there is RGB return on pins 13-9-5 of the SCART and it correspond to DVI-I C5 pin(Analog GND).

What do you think?

[Zebidee]

We don't really know how good the connections are on those passive DVI to VGA adapters. They're often cheaply made and can become a point of failure in the line.

A good point and fair enough.

The C5 pin on DVI is analog GND. It's connected to the shields of each RGB wires. I don't know if TV need these but there is RGB return on pins 13-9-5 of the SCART and it correspond to DVI-I C5 pin(Analog GND).

Those RGB "shields" double as RGB grounds, or "RGB returns".

Yes, those SCART "RGB return" pins are same as "analog GND". They must be connected to DVI C5 pin (analog GND). This is exactly what I was talking about when I said:

- Run all your VGA RGB+sync grounds (5,6,7,8,10) together to one wire and a single SCART ground (choose whichever is convenient). For DVI-I end they're already joined [at C5] .

Your latest diagram looks right. I think it'll work as-is, but I'd be tempted to separate the "analog GND" and "Blanking ground":

• Run "Analog GND" (DVI C5) to a separate SCART ground pin (like one of those "RGB return" SCART pins 13-9-5), to keep it away from the RGB blanking ground. Like you did in your original USB/MOLEX diagrams, except you don't need to split it out three ways. You don't need to connect C5 to all the "RGB returns", just one of them.
• Run DVI 15 ("ground") to SCART 18 ("blanking ground"), like in your diagram. This will give your blanking voltage a more direct and dedicated ground path

For the practical purposes of these diagrams "RGB return" = "RGB shield" = GND = video ground = analog ground = audio ground = ground. These grounds have different names but are most likely all connected together at the video card end, and again at the TV end. You can check this with a multimeter.

However, and this can be confusing: Don't connect anything to "Shield ground", the mesh stuff that goes around the entire cable - this is bulk cable shielding, used for trapping signal interference, so you don't want your video grounds connected to it.

[Dodonpachinko]

The C5 pin on DVI is analog GND. It's connected to the shields of each RGB wires. I don't know if TV need these but there is RGB return on pins 13-9-5 of the SCART and it correspond to DVI-I C5 pin(Analog GND).

Those RGB "shields" double as RGB grounds, or "RGB returns".

Yes, those SCART "RGB return" pins are same as "analog GND". They must be connected to DVI C5 pin (analog GND). This is exactly what I was talking about when I said:

- Run all your VGA RGB+sync grounds (5,6,7,8,10) together to one wire and a single SCART ground (choose whichever is convenient). For DVI-I end they're already joined [at C5] .

Indeed, sorry for missing this.

Your latest diagram looks right. I think it'll work as-is, but I'd be tempted to separate the "analog GND" and "Blanking ground":

    Run "Analog GND" (DVI C5) to a separate SCART ground pin (like one of those "RGB return" SCART pins 13-9-5), to keep it away from the RGB blanking ground. Like you did in your original USB/MOLEX diagrams, except you don't need to split it out three ways. You don't need to connect C5 to all the "RGB returns", just one of them.
    Run DVI 15 ("ground") to SCART 18 ("blanking ground"), like in your diagram. This will give your blanking voltage a more direct and dedicated ground path

I know the grounds are utlimately the same on each side but i was wondering if the TV needed these 13-9-5 ground pins connected on the SCART side.

Anyway, it should look like that with analog ground separated from blanking ground: https://imgur.com/a/7AmlwQ6

I'll try to build it and will come back with feedbacks.

Thanks a lot Zebidee!

[Zebidee]

    Run "Analog GND" (DVI C5) to a separate SCART ground pin (like one of those "RGB return" SCART pins 13-9-5), to keep it away from the RGB blanking ground. Like you did in your original USB/MOLEX diagrams, except you don't need to split it out three ways. You don't need to connect C5 to all the "RGB returns", just one of them.
    Run DVI 15 ("ground") to SCART 18 ("blanking ground"), like in your diagram. This will give your blanking voltage a more direct and dedicated ground path

I know the grounds are utlimately the same on each side but i was wondering if the TV needed these 13-9-5 ground pins connected on the SCART side.

You really don't need all those RGB ground pins connected - that would be overkill. In practice manufacturers know/knew it too and designed to common industry standards. Those grounds are always closely connected on the device-side, and commercial cables almost never connect all those grounds individually. Makes more sense and makes things easier for us.

Even separating the analog ground from the blanking ground might be reasoned unnecessary, it'll probably work OK anyway. They are ultimately connected at each end. However while it might look great in a theoretical SPICE model, pathways/proximity/wire resistance etc. also matter when it comes to signal interference and electronic design. Connected a metre or two down a cable is different to connected 1cm away on a PCB.

Anyway, it should look like that with analog ground separated from blanking ground: https://imgur.com/a/7AmlwQ6

I'll try to build it and will come back with feedbacks.

Thanks a lot Zebidee!

Cheers and no worries     

That design looks perfect! Looking forward to build pics!? 

[Dodonpachinko]

I think we could integrate a micro switch in the SCART shell for enabling Composite SYNC: https://imgur.com/a/nonxeSr

I probably can make it accessible from the outside with some precise cuts and superglue on the SCART plastic shell...

I'll try to post build pics for the cable.

Thanks again!

[Zebidee]

I think we could integrate a micro switch in the SCART shell for enabling Composite SYNC: https://imgur.com/a/nonxeSr

I probably can make it accessible from the outside with some precise cuts and superglue on the SCART plastic shell...

Fancy!

Last time I went very basic. I have a bunch of small wires with Dupont connectors (Often used for breadboard or "arduino"-type builds, similar to mainboard headers connectors for front USB ports, audio LEDs, etc), so I chopped ends off a couple (one male, one female) and soldered them into the V sync line. For the SCART end I just included the wire end in the crimp (described above). Have to open the SCART housing to change it, but that is not too difficult and doesn't happen often.
For example: https://www.aliexpress.com/i/1005004062991289.html