Dreamcast Internal VGA modification

[RedDragunee]

If you like your games to look the best, as myself, you probably already know that VGA is the only true solution for the Dreamcast. VGA-boxes aren't rare at eBay, but the only VGA box to deliver 100% perfect signal, is the original one. Those can be rather expensive these days. Therefore, we want to add an internal VGA port, and attach it directly to the mainboard - it gives the same perfect signal, as the original box, it's much cheaper and most 3rd party VGA-boxes sucks, compared to this solution. Of course, this requires to rip your machine appart, and make cosmetic changes as well.

Most people are already aware of mmmonkey's guide, but his print-schematic seems to contain some errors. E.g. V and H sync have to go through the 150 ohm resistors, as the first thing from the Dreamcast board, and they don't on his print.

Anyway, here's what I've made. I started drawing a schematic myself, which is 100% correct.

http://img238.imageshack.us/img238/7892/1stor.th.gif (http://img238.imageshack.us/i/1stor.gif/)


The best thing would probably be starting with the board. As the image above says, you'd need these components:

2 x Diodes
2 x 4700 ohm resistor
2 x 150 ohm resistor
3 x 220uF capacitors

My result:

http://img394.imageshack.us/img394/4509/17742788.th.jpg (http://img394.imageshack.us/i/17742788.jpg/)

The next thing I did, was to solder the first bunch of wires, to the VGA pins, as shown on my drawing. The last thing I did, was to solder the last bunch of wires directly on the back of the Dreamcast motherboard. Ain't no big deal really, but to make it all fit, was more of a challenge. I might have used to big wires for this.

http://img340.imageshack.us/img340/594/92123062.th.jpg (http://img340.imageshack.us/i/92123062.jpg/)

Anyway - I solved the problem, by only keeping the switch on the back of the case. Next, I placed the VGA and Minijack -sockets in the old modem (I never used it anyway)

http://img97.imageshack.us/img97/6413/18979558.th.jpg (http://img97.imageshack.us/i/18979558.jpg/)

http://img243.imageshack.us/img243/8332/67260143.th.jpg (http://img243.imageshack.us/i/67260143.jpg/)


The results *trada*

http://img26.imageshack.us/img26/4875/54191748.th.jpg (http://img26.imageshack.us/i/54191748.jpg/)

Any problems or questions, please feel free to ask ;-)

[Barc0de]

so this forces true non-interlaced RGBHV for ALL games, not just the ones supporting the VGA box?

[RedDragunee]

As far I remember, not all "non-VGA" games can be forced, but some :dance:
Anyway, with this, it's also possible to have both VGA and RGB -cables connected at same time.

[TmEE]

The H and V and C sync are all active at once. I build my own C sync out of H and V sync... I have the internal VGA box mod done to my DC so that if I have my RGB cable connected, it uses regular RGB mode, if VGA is connected then it goes into non interlaced RGB mode.. otherwise it will be in composhit/s-vid mode.

[drakon]

looks great. I wonder why the regular cables are so hard to find.

[KIWIDOGGIE]

I like this mod, it makes my Dreamcast actualy worth putting on a Monitor Switchbox.

Sweet. and Looks great!

[Martin]

Debating doing this mod. Do you know anything about adjusting the laser current so that I can read CDRs more easily? One of my PAL units struggles sometimes... I only have one VGA box - and I would like to use that in the lounge.

One question though... could you detail the sound mod a little more?

I'll head off to Maplin on the way home from work if I can get some good answers. I suck at electronics - could you list everything I need... i.e. what are the 'diodes'?

[XxHennersXx]

whoo this is awesome.

[RedDragunee]

Debating doing this mod. Do you know anything about adjusting the laser current so that I can read CDRs more easily? One of my PAL units struggles sometimes...
I can't really help you on that one, sorry - maybe another forum member got the answer :confused:


One question though... could you detail the sound mod a little more?

There ain't much detail about the sound-part really - it's just a mini-jack socket, with three pins (L, R and ground) soldered directly to the outputs on the Dreamcast mainboard.



I'll head off to Maplin on the way home from work if I can get some good answers. I suck at electronics - could you list everything I need... i.e. what are the 'diodes'?
3 x 220uF capacitors
2 x 4700 ohms resistors
2 x 150 ohms resistors
2 x diodes
1 x 15 pin D-Sub she (VGA) socket
1 x Mini-jack socket
1 x Switch (6 pins - http://el-supply.dk/Shoppix/60162.JPG)

Circuit board (this type: http://el-supply.dk/Shoppix/7602.JPG)

Capacitors are radial-type.

I don't know the correct english name for those diodes I've used, but translated directly, it's "small-signal diodes - 100V - 0.2A".

[Martin]

That's great - thanks! I'll see what I can do. Would be great to have built in VGA.

[link83]

The diodes are usually called '1N4148' diodes. This may also be a helpful guide to read:-
http://www.mmmonkey.co.uk/console/sega/dc-vga.htm
Hope the OP doesnt mind me linking to another guide

[Tchoin]

Thanks for sharing ! It looks damn interesting, maybe I'll try it soon

[RedDragunee]

http://www.mmmonkey.co.uk/console/sega/dc-vga.htm
Hope the OP doesnt mind me linking to another guide
Nope, it's fine.

As long as people are aware of, that the circuit board on mmmonkeys page, isn't correct (as I wrote above). I've seen a couple of people, following his guide 100%, and they all had their Dreamcast fried :-)

[Yakumo]

This is a cool mod! I think I'll try it on one of my Dreamcasts. I have one that gives no image via the multi out at the back so I think that could be the one to mod. I already have 1 Dreamcast set up with the official VGA box so it would be nice to compare the two, not that there's going to be any difference I guess.

yakumo

[Martin]

The diodes are usually called '1N4148' diodes. This may also be a helpful guide to read:-
http://www.mmmonkey.co.uk/console/sega/dc-vga.htm
Hope the OP doesnt mind me linking to another guide

I ended up having to get different diodes because of stock issues. Will post back with results. They have a similar rating. I hope nothing breaks!

[RedDragunee]

I found my shopping list just a minute ago, and as link83 wrote, it's the 1N4148 diodes I've used. Are you gonna try using two different diodes? If so, I can't guarantee for the results :shrug:

[Martin]

I am crap at mods... :noooo:

[link83]

As long as people are aware of, that the circuit board on mmmonkeys page, isn't correct (as I wrote above). I've seen a couple of people, following his guide 100%, and they all had their Dreamcast fried :-)
Yes - that happened to me too!
However, I emailed mmmonkey to let him know the error a couple of months ago and since then and he has updated the circuit board picture so it should be fine now. The component 'ordering' still isnt the same as that used on the original circuit diagram, but this shouldnt matter.
I have a circuit board picture somewhere that I corrected myself to match the original diagram exactly - if anybody is interested I will try and dig it out...

[ninjux]

i have a third party vga box from ebay and the picture looks fine,but it works only with games that support the vga box.can you play ALL games through this vga mod?(even not in the best quality picture)i just don't want to swich between my pc monitor and the tv for the games that don't support vga.

as for mmmonkey i broke a saturn when i lifted the leg from the ic to do the 50-60 hertz mod,i accidentally pull the wire,and the leg was gone off the ic :(..althought his guides are well detailed some things he say suck really bad.i was stupid trying that.on my other saturn i just cut the trace and connected it like all the other guides(even if you make a mistake it wont kill your saturn)

[DC_Fan]

Cool, I might try this someday when I have nothing to do.:thumbsup:

[Treamcaster]

Your diagram and info is hella interesting!


Now to the questions ^^

1-Do ya know if this mod makes the vga signal better than this vga box?
http://www.racketboy.com/retro/vgabox3.jpg

2-What is the best shop to buy all these stuff? I have no electronics knowledge and so I would be very gratefull if you could give me that info.

3-When your running a DC game, do you have 2 black bars on each side of the screen, or can you play full 16:9 with no black stuff? Same question for 4:3.

4-I would like to do, or ask someone to make me a Digital audio mod as well. My question is, can I use VGA and digital sound at the same time?

Thanks in advance!

[RedDragunee]

Thank you! I'm glad to hear people appreciate it :)


1-Do ya know if this mod makes the vga signal better than this vga box?
http://www.racketboy.com/retro/vgabox3.jpg

Without question, it does!

I've owned both the transparent one, and a black one from "Brooklyn", I think it was. The transparent box, showed some clearly visible horizontal lines, sometimes more or less, depending on the game. The Brooklyn box did so too, and as a bonus, it just wouldn't work on certain televisions. A friend of mine owns the original VGA box, and the picture you get from this mod, is just as great - we've tested!


2-What is the best shop to buy all these stuff? I have no electronics knowledge and so I would be very gratefull if you could give me that info.

To be honorst, I don't have a clue. Google a online local-store would be my best advice - maybe another member knows more precisely? :shrug:


3-When your running a DC game, do you have 2 black bars on each side of the screen, or can you play full 16:9 with no black stuff? Same question for 4:3.

Haven't really tried that myself, because I usually like to play games in their original aspect. Guess it depends on your TV though.


4-I would like to do, or ask someone to make me a Digital audio mod as well. My question is, can I use VGA and digital sound at the same time?
Again, haven't tried that myself, but I can't see why you wouldn't be able to ;-)

[alecjahn]

Wow, man. Nice job. I like it when tutorials are made easy with a nice simple diagram instead of just a schematic I have to fumble my way through.

I was going to do a VGA mod to one of my DCs a while back, but then my mom got scared and said you're movin with your auntie and uncle in Bel Air.


I mean, uhh, I just bought RacketBoy's box dongle instead. If I get the mod done (working on other things...) soon I'll try and bust out some comparisons.

[Treamcaster]

Thanks for the answers dude.
Here's what I mean, uploaded specially for you:
http://www.youtube.com/watch?v=2tRzEBAXQHQ

[-=FamilyGuy=-]

Cool and nicely done!
Shouldn't 4k7 be 47k on the diagram though ?

FG

[RedDragunee]

Thank you very much!
And no, it shouldn't ;-)

[gorgyrip]

the switch is really necesary? isn't it possible to connect the rgb and vga lines to 2 gnd pins of the vga connector? because all gnd pins are linked in the monitor.

[link83]

the switch is really necesary? isn't it possible to connect the rgb and vga lines to 2 gnd pins of the vga connector? because all gnd pins are linked in the monitor.

Yes you can do that :nod: but the advantage of a switch is that you can 'trick' some Dreamcast games that are usually incompatible with VGA output into VGA by simply flicking the switch from 'standard' to 'VGA mode' after the game has started to boot (On original GD-ROM's you flick the switch just after you hear the 'beep' from the GD Drive, with CD-R software you wont hear any beep)

If you used the grounds pin on the VGA socket you would need to disconnect and reconnect the cable to perform the same trick which would quickly wear out the VGA plug/socket (In fact this is what some people used to do with Dreamcast VGA boxes which didnt have a switch, but they ended up wearing out the Dreamcast's AV socket)

[gorgyrip]

You can also use ipwriter to add vga support to any game.

[Christer-swe]

You can also use ipwriter to add vga support to any game.

How?

[_SD_]

I was going to do a VGA mod to one of my DCs a while back, but then my mom got scared and said you're movin with your auntie and uncle in Bel Air.

:thumbsup: I actually lol'ed...

[gorgyrip]

i did this mod, but now my dreamcast isn't working.i have this problems:
1. on the dreamcast logo, the "S" letter is flickering
2. when i go to the VMU menu, i get the blue background and nothing else.
3. when i go to settings, i get to set the time again, and after that white screen.
4. when i have to set the time i get some strange horizontal lines. see the photo.

[MentalMan]

Just finished up a unit, sure was fun. Now I do still have to sort out holes for the vga socket, switch and audio socket but that is cosmetic. A little crappy Picture (http://emotion-pixels.com/ftp/dcvga.jpg) of the gutted sexbot.

This unit is actually a gift for a friend, also flashed the board to NTSC/J. Gonna kick him off into the awesome world of dreamcast with style.

My chipped HKT-3010 will most likely be next in line.

Thanks to everyone from whom I endet up taking information for this, especially RedDragunee! :thumbsup:

Edit: finished up the internal unit case fitting a few days ago and today I made my own VGA cable, since I went against cutting up my japanese unit. Fun!

[aryssoR]

Any chance you could re-upload the original images in the first post?

Thanks!

[RedDragunee]

Duh, stupid me. Sure thing :katamari:

[aryssoR]

Excellent, thanks again. Planning to do this mod on one of my DCs

[aryssoR]

Just finished this mod on one of my Dreamcasts, I ended up having to substitute some of the components (which I harvested from a broken phone lol:

150R > 100R
220uF > 100uF 10v
1N4148 > 1N50R

Worked absolutely perfectly, I'll take a pic of it tomorrow when my wife gets back with the camera.

I was hoping the switch would fool Last Blade 2, but I can't seem to get it to work, so I may not bother cutting it into the case (at the moment it's tucked inside)

Props RedDragunee, mmmonkey, etc

[aryssoR]

Here's my go, I could do to tidy up the wiring inside, but it works, that's the main thing

http://i19.photobucket.com/albums/b165/Grand_cross/dcmod1.jpg

http://i19.photobucket.com/albums/b165/Grand_cross/dcmod2.jpg

http://i19.photobucket.com/albums/b165/Grand_cross/dcmod5.jpg

http://i19.photobucket.com/albums/b165/Grand_cross/dcmod3.jpg

http://i19.photobucket.com/albums/b165/Grand_cross/dcmod4.jpg

[RedDragunee]

Looks great :clap:
I've just received another Dreamcast, so I'm about to do the modification once again.

[TmEE]

http://www.fileden.com/files/2008/4/21/1876835/DCback.jpg
http://www.fileden.com/files/2008/4/21/1876835/DCoverview.jpg

my DC (I do not like cutting holes into my own stuff).

[MrComputerRevo]

Hey! Can somebody show underneath of board with capacitors? I am confused where to solder wires....

[segadreamsat]

Hello !
I've done this VGA Mod, but I'm disappointed with the result :
the image is steady, with the good colors, but has some kind of interference. It looks like those colors fade gradually to the right, as you can see on the picture.
Do you know where it could come from ?
I used wires from a SATA ribbon cable, so those wires are very thin and stuck together, I don't know if it could be the reason...

[jinn]

I tried the mod a few years back and it seem to be a PAL DC mod. I tried it on my US DC and it wouldn't work, then I tried to hook up the MoBo points straight to the D-Sub and it work first time. My mod did not need the
2 x Diodes
2 x 4700 ohm resistor
2 x 150 ohm resistor
3 x 220uF capacitors

[APE]

VGA is analog so it is extremely susceptible to interference. If you just used the wires one after another in a row (think ribbon cables) without grounding a wire in between each of the wires carrying a signal (ABCDE - B and D would be grounded where A, C and E are carrying an analog signal) it could introduce crosstalk but I can't tell you exactly what it looks like as I've never seen it on a VGA display before. Nor have I actually seen that particular problem before.

I'd make sure everything is properly grounded and shielded. I'd also check into how large a gauge wire you should be using for this. Wires from a SATA cable might be too high a gauge for this for all I know.

[segadreamsat]

Thank you all for your help ! With your advice, I applied several changes, and it finally works well !

Here is what I did, if it can help someone :

- I used a stripboard with pre-linked slots as shown in the tutorial (instead of my 1st board where all the slots were separated) -> less solder/wires
- I used much bigger wires between the stripboard and the VGA socket (instead of my IDE ribbon cable (yes, IDE and not SATA as I said before, it was a mistake))
- I still used IDE ribbon cable between the motherboard and the stripboard (much easier to solder to the motherboard), but this time, I took 13 wires, and used only 7 of them, leaving a "useless" wire between 2 "useful" wires (if you prefer, if they were numbered from 1 to 13, I used only the odd ones).

Thanks again !

[Calpis]

What you were seeing is ghosting from signal ringing from improper termination. Perhaps the cable was long? Or it could have been the mismatching of the cable's characteristic impedance.

[segadreamsat]

I don't know exactly where it came from. I don't think it was related to the length of cables or wires as I used exactly the same VGA cable and more or less the same length for wires for my 2 trials. Actually I think they are a bit longer this 2nd time, but not much (1cm or 2).

I also noticed that the colors are a little "darker" using VGA than using original RGB output. I guess it's normal as I saw the same thing comparing HDMI and VGA on a X360. Do you know why this happens ? Can we change this, maybe by using different capacitors ?

Once again : thanks !

[ArgyleEyes]

im just gonna ask here for randomness and lazyness not to post a new thread....so yeah sorry if need be...

in short i killed my dreamcast being foolish and not keeping track of screws...(*cocky*)
if you know what about im talking about then yeah...im wondering if i could possibly make a fix by doing a vga mod even though the video got screwed...literally...least the sd card mod worked XD

..new dreamcasts are like $50 here at the "gamer pawn store" T_T *sigh*

as for above just to add you could always test other caps or add pots to the whole process i think to get fine tuning out of it?

[DCCharlie]

I hate to bring an old thread to life but I did this mod, but I got the weirdest issue. My picture shows in Grey scale only on my monitor. I've tried 3 different monitors and they are all grey scale. I tried a second VGA connector, with the same results. I do not currently have the proper Dreamcast can=bles to verify the system was displaying in color but I have read this will usually work or not work, nothing in between.

[RedDragunee]

That sounds really odd. Have you tried checking all connections, components etc. to see if they're all placed correctly, and soldered properly? Are the components exactly the same as listed in the tutorial? Are they used, or brand new?
Have you tried a different VGA-cable, just to make sure?

[DCCharlie]

That sounds really odd. Have you tried checking all connections, components etc. to see if they're all placed correctly, and soldered properly? Are the components exactly the same as listed in the tutorial? Are they used, or brand new?
Have you tried a different VGA-cable, just to make sure?

Oddly enough, I located a random post on a random website that the guy mentioned he has an American DC and he didn't need the PCB. So for the heck of it I tried it and it worked! All color! Go figure I guess.:biggrin-new:

[RedDragunee]

Good to hear :)

[SnoopKatt]

Nice! One more thing to add to my project list :p

[simbin]

With racketboy and others gouging people for cables, I was wondering if anyone has successfully made their own? I'm not so great with a soldering iron and dremel, so I'd rather try making a cable instead of preforming surgery on my Dreamcast.

[APE]

With racketboy and others gouging people for cables, I was wondering if anyone has successfully made their own? I'm not so great with a soldering iron and dremel, so I'd rather try making a cable instead of preforming surgery on my Dreamcast.

Where are you going to get the connector? SCART cables don't have all of the wires necessary for VGA as far as I'm aware and you can't cannibalize composite cables.

[synrgy87]

a vga cable off an old crt monitor or even a new one, the actual dreamcast connector would be the only problem. maybe a DC RGB scart cable just using the connector i think they have all the pins? could be wrong though.

[APE]

a vga cable off an old crt monitor or even a new one, the actual dreamcast connector would be the only problem. maybe a DC RGB scart cable just using the connector i think they have all the pins? could be wrong though.

VGA is RGB, H-SYNC, V-SYNC, +5, GND. All but the two sync signals are available on the SCART connector unless they wired everything in there for no apparent reason. On top of that you need to have a switch to engage VGA mode which requires an additional pin very likely not wired into the SCART connector.

[synrgy87]

VGA is RGB, H-SYNC, V-SYNC, +5, GND. All but the two sync signals are available on the SCART connector unless they wired everything in there for no apparent reason. On top of that you need to have a switch to engage VGA mode which requires an additional pin very likely not wired into the SCART connector.

i simply meant using the DC side of the scart cable if all the pins are in the connector then wuld just need to be connected and a switch added in-line

[-=FamilyGuy=-]

I’m planning to make a smt version of this + scanline, and I have a few questions.
Is 1/8 W enought for the 4.7k ohm resistor? (I’m not sure)
Is 1/4 W enought for the 150 ohm resistor? (I think so)
Is 25V enought for the 220 uf capacitor? (I think so)
Shouldn’t there be a 0.1 uf ceramic capacitor in parallel with the 220 uf one?

Talking about this schematic from mmmonkey:
http://i620.photobucket.com/albums/tt286/Argelfraster_2009/DreamcastVGA.gif


Thank you!

[bertmansk]

Seeing as a couple people have mentioned they eliminated the PCB for American DC's, I'm wondering what they did for the +5v for the H & V sync. Just jump them, or put a switch...?

[Starfire]

I know it's bringing up an old thread, but I tried to add a VGA to my Dreamcast using the Stripboard design and had no luck, built and tested it a couple times. It just happend that I found this thread that said someone tried the mod just wired straight though and guess what worked perfectly for me so I just wanted to let others know, plus I also made a diagram how I wired it. This might be risky I have no idea but works perfectly for me, tested on 3 monitors and 1 TV perfect on all of them. Here is the Diagram 6806