S-video mod

[jaxmazon]

Hi guyz I found out about a megadrive 1 s-video mod and im really interested in doing it but I not sure if I can pull it off. I have done a switch mod for my megadrive 1 and it works perfectly.

heres the mod http://www-unix.ecs.umass.edu/~dhowland/mod/

If I do this mod will it stop the sync issues with cheap LCD tv's and is it worth it?

[moonmaster1]

It would be worth it for the sharper image output.

I have had problems with s-video though and if you have a problem where s-video shorts out on your tv from time to time, i would just get av cables instead.

[jaxmazon]

It would be worth it for the sharper image output.

I have had problems with s-video though and if you have a problem where s-video shorts out on your tv from time to time, i would just get av cables instead.

oh okay well I might try and do it because I would like to have the best image possible for my megadrive but I heard that you can get the megadrive to run componet

[villahed94]

NOOOOOOOOOO
DON´T try that mod, use jamma-x nation one, it is easier and delivers an even better image. Just google it.

[jaxmazon]

NOOOOOOOOOO
DON´T try that mod, use jamma-x nation one, it is easier and delivers an even better image. Just google it.

you mean this one http://www.jamma-nation-x.com/jammax/genesismods.html its not very useful since it doesn't have much information about building the s-video mod I have to amit it looks much better but it explains more about making a megadrive 1 and sega cd 2 run from one psu than the s-video mod or is this the wrong mod?

[villahed94]

No,it's right just read it let me remember it in 2 hours(i'm at school)

[jaxmazon]

No,it's right just read it let me remember it in 2 hours(i'm at school)

:) okay thanks

[villahed94]

OK, I´ve returned
The following parts you need:
1 NTE85 or similar NPN general purpose transistor
1 220 uF Electrolytic or tantalum capacitor
1 0.25 W 27 ohm resistor
1 0.25 W 75 ohm resistor.
(the resistor values can be changed at desired, i used a 56 ohm instead of the 75 )

For Luma amp:

http://www.jamma-nation-x.com/jammax/images/nte85luma.jpg
This means that the pin 16 signal must go on the right leg, the center one, must go on a +5 v source(you can use the Voltage regulators on it) and then in the left leg, you should put the resistor and after that you have a useful signal for Luma (use a PCB mountable S-Video Female Connector) .

For chroma is easier :
Take the signal from the pin 15 and connect it to the NEGATIVE side of the cap, then put the 75 ohm resistor and there you go, another useful signal.

For grounding, connect the 2 pins from the S-Video female to any metal part, like the screws on the voltage regulators or the RF Shield.
http://www.bigmech.com/misc/c64mods/s-video_pinouts.jpg
A useful pinout.

Well, that´s all. Don´t forget to add a rep!(click on the scale)

[jaxmazon]

OK, I´ve returned
The following parts you need:
1 NTE85 or similar NPN general purpose transistor
1 220 uF Electrolytic or tantalum capacitor
1 0.25 W 27 ohm resistor
1 0.25 W 75 ohm resistor.
(the resistor values can be changed at desired, i used a 56 ohm instead of the 75 )

For Luma amp:

http://www.jamma-nation-x.com/jammax/images/nte85luma.jpg
This means that the pin 16 signal must go on the right leg, the center one, must go on a +5 v source(you can use the Voltage regulators on it) and then in the left leg, you should put the resistor and after that you have a useful signal for Luma (use a PCB mountable S-Video Female Connector) .

For chroma is easier :
Take the signal from the pin 15 and connect it to the NEGATIVE side of the cap, then put the 75 ohm resistor and there you go, another useful signal.

For grounding, connect the 2 pins from the S-Video female to any metal part, like the screws on the voltage regulators or the RF Shield.
http://www.bigmech.com/misc/c64mods/s-video_pinouts.jpg
A useful pinout.

Well, that´s all. Don´t forget to add a rep!(click on the scale)

Thanks for the help villahed94 I gave u some rep :) btw can I use these transistors http://cgi.ebay.co.uk/12-x-2N3904-NPN-Transistors-qd018-/290439219312?pt=UK_BOI_Electrical_Components_Suppl ies_ET&hash=item439f86c870 for some reason I can't seem to find the NTE85 transistors :( and also will this make my megadrive 1 output stereo sound?

[villahed94]

Nope the stereo sound can be obtained from the headphone jack, use a generic jack to RCA cable, it would work. And 2N3904 is perfect, it is the one I used, so you can use it.


Woohoo I´ve done 250 posts so going to.....
WCPO Agent! Thanks to all guys at Sega 16 who has made me to encourage and get this!

[jaxmazon]

dam it I can't seem to find the CXA1145 chip on my motherboard :( I have a PAL megadrive does this mean I can't do the S-video mod?

[KillerBean2]

You need to remove the voltage regulator cooling plate in order to get to it.

http://www.mastersystem.dk/stuff/pics/megadrive1_video.jpg

But you say you have a PAL Megadrive. Do you live in Europe or do you live in the US? If you live in Europe, why don't you just use a SCART RGB cable? It's the best there is.

[villahed94]

Yeah, remove the plate, but you can do the mod, no matter the region of the system

[jaxmazon]

I have removed the heatsink and its not there its only a very small chip :( theres only a smaller chip and the reason I don't want to use RGB is because I want to get the best quality picture possible.

[KillerBean2]

and the reason I don't want to use RGB is because I want to get the best quality picture possible.

But RGB IS the best quality picture possible!

http://nfggames.com/atarilabs/meat/2000/1201_videoprimer.shtml

[jaxmazon]

But RGB IS the best quality picture possible!

http://nfggames.com/atarilabs/meat/2000/1201_videoprimer.shtml

oh dam lol btw thats a good read thx Killbean and villahed94

[villahed94]

You´re welocme, if you have a problem, you can contact me!

[jaxmazon]

You´re welocme, if you have a problem, you can contact me!

Thanks again, I just found out something very strange and Im a bit upset lol the motherboard killbean showed is a 1992 motherboard and I have a 1993. The chip on my 1993 motherboard is alot smaller and still has the same amount of pins so Im guessing I can still do the mod on my 1993 motherboard. I also noticed that the 1992 motherboard doesn't have the JP1,2,3,4 well I couldn't see them so I can't move my switch mod onto the 1992 board :(. The main reason im doing the s-video mod is that my tv suffers the RGB shift where the picture is 15% to the right :(.

again thanks for the help guyz

[Jorge Nuno]

Seems to be like a VA6.8 or a VA7 pcb revision (or maybe an unknown one? <- In this case PICS PLZ :p).

To fix your "RGB shift" you need to use the CSync signal (all RGB cables using the video signal as a sync suffer from this)

[jaxmazon]

Seems to be like a VA6.8 or a VA7 pcb revision (or maybe an unknown one? <- In this case PICS PLZ :p).

To fix your "RGB shift" you need to use the CSync signal (all RGB cables using the video signal as a sync suffer from this)

CSync signal? how do I use that to fix my RGB shift? thanks

[Jorge Nuno]

Well you have to modify the cable or the connector and you also need a resistor of 0.5k~1kOhm, take out the composite video signal and put CSync with that resistor/potentiometer in series

[TmEE]

I'm now wondering how will the Csync fix the RGB shift... I have a jumper in my MD to select between the Csync and Cvideo for sync for SCART and in both cases the image stays where it is...

[Jorge Nuno]

Well yeah there isn't any difference, I appologise.

I guess my TV was calibrated already for the MD :p

[jaxmazon]

Well yeah there isn't any difference, I appologise.

I guess my TV was calibrated already for the MD :p

no worries thx for help btw I giving rep for people who try to help :). Anyway Im gunna try to mod my megadrive with s-video asap when I finish I will post pictures

[cityofc]

I would be interested in seeing pictures and getting your opinion of the difference in video.
Thanks.

[villahed94]

Ok, post us, but try TmEE´s csync, it should work no more off-centered screen.
By the way post pics of image and board, the chip it´s maybe a smaller version of the cxa1145, it should work as well.

[MindController]

NOOOOOOOOOO
DON´T try that mod, use jamma-x nation one, it is easier and delivers an even better image. Just google it.

I wish I had seen this thread when I started and failed my first two attempts lol.

Yay for easy mods!

[jaxmazon]

Ok, post us, but try TmEE´s csync, it should work no more off-centered screen.
By the way post pics of image and board, the chip it´s maybe a smaller version of the cxa1145, it should work as well.

Okay heres a megadrive board that I have that uses the normal cxa1145 chip

http://img801.imageshack.us/img801/6964/img1532d.jpg
By ssj4jaxmazon (http://profile.imageshack.us/user/ssj4jaxmazon) at 2010-09-13

and heres the board I am using which has the switch mod installed and the small chip (I know its messy lol)

http://img837.imageshack.us/img837/9818/img1537r.jpg
By ssj4jaxmazon (http://profile.imageshack.us/user/ssj4jaxmazon) at 2010-09-13

heres the chip upclose sorry for blurry picture

http://img696.imageshack.us/img696/6200/img1539u.jpg
By ssj4jaxmazon (http://profile.imageshack.us/user/ssj4jaxmazon) at 2010-09-13

The chip has the same amount of legs as the cxa1145 so I guess the s-video mod will still work.

[Jorge Nuno]

Your second board is a VA6.8 and you don't need any amplifier for the SVideo lines with the MB3514.

(If you think your console is messy, you should see mine... :|)

[jaxmazon]

Your second board is a VA6.8 and you don't need any amplifier for the SVideo lines with the MB3514.

(If you think your console is messy, you should see mine... :|)

what do u mean? how do I do the s-video mod?

(actually ignore that question lol, do u know what number each leg is?)

[Jorge Nuno]

Pin 15 is chroma and pin 16 is luma. The mod in this case is really simple, you just need 2 resistors and 2 caps maximum.

[villahed94]

Jaxmazon, don´´t worry my explanation works both for CXA1145 and MB3514, they have the same output and pinage

[jaxmazon]

Right I just finished modding my megadrive with s-video and I was unsucessful :( I don't understand what I did wrong I soldered everything correctly. I did however not use a PCB mountable s-video connector could this be the reason its not working? my tv detects that there is s-video but when I turn on my megadrive nothing happens and yes I have a game inserted.

[SithWarrior]

Hi if I were to do this mod would I still able to use the RGB scart cable in the future?

[villahed94]

Of course sith, rgb can still be used. but jax... is the soldering point fresh? No pin shorting? Are the minicaps in good state? How many W is your soldering iron? The last one matters because I killed 2 Genesis with an 80 W iron!!

[SithWarrior]

Thanks villahed for the reply once I get some time and the parts I'm gonna try this out on a VA6

[villahed94]

You´re welcome, add some rep if it was helpful!

[Kingbuzzo]

I did the mod based on the Jamma Nation X tutorial with the kit they sell.

they posted kit instructions here (http://www.jamma-nation-x.com/jammax/neogeosvideo.html). Keep in mind that the mod is for a Neo Geo AES but it uses the same CXA1145 encoder chip.

A word of advice, on my Model 1 Revision 1.5, I had vertical lines all over the place. I added a 1k B pot to the chroma line in between the 4pin din, and the positive leg of the capacitor. I usually have it set around 480-500 and sometimes more.

My mod...

http://i3.photobucket.com/albums/y85/k1ngbuzzo/th_svideo.jpg (http://s3.photobucket.com/albums/y85/k1ngbuzzo/?action=view&current=svideo.jpg)

The image truly does look great though. Scanlines and colours coming in beautifully.

I also used their guide plus a few emails of their own guidance to have only one AC adapter powering both the model 1 Sega CD and model 1 Genesis. I used a 9V 4.5a PSU for some Nikon Camera and a 2.1mm power barrel daisy chain that guitar stores will sell for Effects pedals. Just had to make sure I had it was centre negative.

Long story short, my eyes are happy, and so is my wall outlet!

[jaxmazon]

Of course sith, rgb can still be used. but jax... is the soldering point fresh? No pin shorting? Are the minicaps in good state? How many W is your soldering iron? The last one matters because I killed 2 Genesis with an 80 W iron!!

Hmm my iron is 50w so that can't be the issue.. Could it be that I have put the transistor on a board? I did it this way since it easier to solder for me

[Jorge Nuno]

Try connecting pin 16 and ground to the Svideo plug directly. It should give you a B/W image, if you did it right.

[jaxmazon]

Try connecting pin 16 and ground to the Svideo plug directly. It should give you a B/W image, if you did it right.

hmm okay but the bottom to pins of s-video are grounded? before you said that all I needed to do it use 2 resistors and two caps could you explain this further please. You said I do not need a amp I am using a transistor is that wrong? btw thx everyone for the help so far I will give everyone rep :)

[villahed94]

No, 2n3904 works well

[SithWarrior]

Another question would anyone know where I could get a the S video Jack in Canada?

[Kingbuzzo]

Another question would anyone know where I could get a the S video Jack in Canada?

I don't know where to source the gold plated jacks, but you can buy them in the mod kit that Jamma Nation X sells. That'd be your best all in one solution.

Otherwise, I consolized a 2 slot MVS with parts from Digikey.

buy the par here..

http://www.jamma-nation-x.com/jammax/images/buz2.jpg


You can either mount them with the nut inside or outside whereas the gold plated ones only mount one way and require some very fine rotary tool (dremel) work to make the mounting flush with the case.

The svideo jack is in stock here..

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CP-2840-ND

[Jorge Nuno]

hmm okay but the bottom to pins of s-video are grounded? before you said that all I needed to do it use 2 resistors and two caps could you explain this further please. You said I do not need a amp I am using a transistor is that wrong? btw thx everyone for the help so far I will give everyone rep :)

For testing, you dont need anything, just wire Y and Gnd (yes both bottom pins are Gnd).

[villahed94]

sith, you can get it at any electronics shop, and jorge, good easy testing way!

[jaxmazon]

For testing, you dont need anything, just wire Y and Gnd (yes both bottom pins are Gnd).

dam it something is wrong I tried this and nothing... I give up this is just too complicated I have now ruined my megadrive. I would carry on doing this but I don't have the money to carry it on since I going to uni tomorrow thanks for the help but it was a no go. Unless im doing it wrong what do I need to do with the MB3514 to output s-video because someone said I just need a couple of resistors and caps to do the mod and no transistor so how do i do it?

Thanks

[Jorge Nuno]

Could you take a picture of what you did? It could help to spot whats wrong...

[villahed94]

Please pics and we´ll ban that guy, because the transistor is mandatory, it amplifies the signal.
Also yeah, it must be done with care, i ruined 2 genesis with an 80 w iron and no care