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Thread: S-Video mod tutorial for the Sega Genesis Model - 2 *ALL V. ENCODERS EXCEPT KA2195D*

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    Raging in the Streets Thunderblaze16's Avatar
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    Megadrive S-Video mod tutorial for the Sega Genesis Model - 2 *ALL V. ENCODERS EXCEPT KA2195D*

    The Sega Genesis model - 2 has the following video encoders, they can all be modded for s-video, EXCEPT the SAMSUNG KA2195D. Not only is it consider the worst video encoder to find on your Model - 2 but it doesn't support s-video.

    -Fujitsu MB3514 ✓
    -Samsung KA2195D X
    -Sony CXA1645 ✓

    Tools Required:

    -Drill/dremel
    -Cross head screwdriver
    -Soldering Iron
    -Solder
    --Cables (Highly recommend 28 gauge cables for better handle. You can find the same wires I used here,)
    http://www.jameco.com/shop/StoreCata...8+gauge+cables
    -Chassis Mount S-video Jack (You can get the gold ones I use or standard ones here.)
    https://console5.com/store/parts/av-jacks-1.html
    -27ohm 1/4 watt Resistor <----(Only for CXA1145M)
    -75ohm 1/4 watt Resistor
    -220uf Electrolytic Capacitor
    -2N3904 Transistor (Or similar) <----(Only for CXA1145M)



    Ok first off, open up the system and remove all screws to the point where you're able to completely take off the board.

    Next, before we work on the board itself. Mark the area on where you want to drill in for your jacks to be placed in.
    I'm working on a VA3 for this tutorial, so I'll be placing them on the side since the VA3 & 4 have a completely empty spot on the side.

    Once you found the place that pleases you, drill in the hole but not too big. Just enough for the jack to fit in.




    Now go to the board and locate the video encoder, found behind, near the cartridge slot.



    This piece is of the tutorial is for the Sony CXA1645 & Fujitsu MB3514 encoders only, this mod works the same on both of them. I will be just mentioning the CXA1645 from here on out


    Now the Sony CXA1645 is WAY easier to mod for s-video. Simply put it.

    PIN 15--------75 OHM-------(+)220UF(-)----CHROMA LEG
    PIN 16--------75 OHM-------(+)220UF(-)----LUMA LEG


    Recommend getting GND again from a 47uF CAP, there usually near the chip.

    Here's a diagram,


    Let's get our resistors and caps soldered together first.



    Next, solder them to PINS 15 and 16 of the Sony CXA1645. To make this simply to understand.

    CHROMA - GREEN CABLE
    LUMA - BLUE CABLE





    Half way done, Now we just need to solder the cables to our s-video jack, along with our GND, so let's begin with the jack from here.

    Take your s-video jack and add some solder to all 4 of it's leg, while having something holding the jack still as you do it.



    Now, take 4 small cable pieces and begin soldering them to the legs, use a knife or something sharp and place in the middle of the jack to make it easier on your eyes and prevent accidentally soldering the legs together.


    My cable selection,

    CHROMA - GREEN WIRE
    LUMA - BLUE WIRE
    GROUND - WHITE WIRES




    Once you know those cables are for sure soldered in, hot glue them in as well.


    Go and lock it in place to where you've drilled for it.
    (Now that I think about it, I've should have just long wired all of them like I did with GND, whoops!)




    Now end it by soldering your Chroma and Luma cables to the cables soldered to the (-) side of the Caps, remember Chroma is PIN 14 and Luma is PIN 15. Also solder your 2 white cables for GND to the negative leg of a nearby 47uF CAP.

    You're done!





    This piece is of the tutorial is for the Sony CXA1145 encoder only.

    This guy is a little more complicated, but doable. It's honestly the SAME as the a model 1 Genesis. Follow this diagram and make sure you have the 27 OHM and 2N3904 Transistor ready!



    The s-video from a Sony CXA1645 is simply gorgeous.




    More pics,
    https://i.imgur.com/CydbEsK.jpg
    https://i.imgur.com/mNol7po.jpg
    https://i.imgur.com/AsCE2Ak.jpg
    https://i.imgur.com/tvV9JBF.jpg
    https://i.imgur.com/tJDVzq4.jpg
    https://i.imgur.com/5kLR732.jpg
    https://i.imgur.com/YJIipHR.jpg











    For more Sega Genesis model - 2 modding tutorials, please visit the following link below.
    http://www.sega-16.com/forum/showthr...ding-Tutorials
    Last edited by Thunderblaze16; 01-27-2018 at 04:37 PM.
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    Raging in the Streets Thunderblaze16's Avatar
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    If you still want to use your Model - 2 that has an Samsung KA2195D, it can still be modded but you need to completely replace the video encoder all together, recommend replacing it with a CXA1645 of course.

    I'm just going to copy and paste what Ace told me.

    After having cross-referenced the application circuits in the CXA1645 and KA2195D datasheets, in order to use the CXA1645 in place of the KA2195D, you need to make sure of the following:

    -20Kohm resistor to Ground on pin 18
    -47Kohm resistor and 0.1uF capacitor to Ground on pin 13
    -0.1uF capacitor to Ground on pin 9

    ADDENDUM: There appears to be more required for the CXA1645 mod to work properly.

    -You must make your own VRef with a 1.5Kohm resistor to VCC and 1Kohm resistor to Ground plus a 10uF filter capacitor. The CXA1645's VRef is EXTREMELY high, almost 4V, and will keep the Genesis in reset for a long time, if not forever. You must cut the trace splitting off pin 14 of the encoder and solder the resistors at the solder spot for L1.
    -If you leave pin 17 floating, the picture gets severe fringing. You must use a small capacitor in series with an inductor of 12uH to get rid of this.

    The overall mod is as follows:

    -Add a 0.1uF capacitor to Ground on pin 9
    -Replace R54 with a 47Kohm resistor and 0.1uF capacitor in parallel
    -Add a 20Kohm resistor at C42
    -Add a ceramic capacitor to C29 (value unknown, it was pulled from the VA2 Genesis 3's video circuit) and a 12uH inductor to L3
    -Add a voltage divider consisting of a 1Kohm resistor to Ground and 1.5Kohm resistor to 5V at L1 (this is VRef for the op-amps) then place a 10uF capacitor to Ground to filter the VRef

    Overall verdict? Much cleaner than the KA2195D. Colors are better (especially reds, which look rather orangey on the KA2195D), picture is slightly brighter and has better contrast. Unfortunately, the vertical lines remain, but they're far more faint than on the KA2195D. It isn't quite as good as the CXA2075, however, which has less fringing and completely kills the vertical lines.

    CXA1645M PINOUT.




    Other sites I've found related to the topic of this thread.
    http://racketboy.com/forum/viewtopic.php?f=25&t=32257

    https://bitsandblips.wordpress.com/2...video-encoder/

    http://www.gamesx.com/rgbadd/genesis3.htm
    Last edited by Thunderblaze16; 01-09-2017 at 02:42 PM.
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    How come you're not trimming your leads? You really should be cutting those component leads down and putting heat shrink over them to prevent a short...

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    Raging in the Streets Thunderblaze16's Avatar
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    I normally do, I just got lazy with this one, mainly since I'm won't be using this system to begin with.
    (Already have a modded model 1 non-tmss, I was never a model 2 guy to begin with)
    This was just more showing the basic of the mod.

    All soldered spots have been hit with hot glue to avoid any shortages instead after these images were taken.
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    I just tried this on my MB3514-encoded VA2.3 (which I had modified to use a 47uH coil on L2 and tweaked up the band-pass filter and delay line to get a sharper composite image), and... uh..

    L-let's just have the picture speak for what this had wrought on my TV screen:
    IMG_0535.jpg

    My potato of a camera doesn't do this justice. It's way brighter and properly saturated in real life. In fact, it's damned near flawless. It looks very much like I'm playing this through RGB (which my TV lacks). There is almost zero color fringing, absolutely no pixellation or vertical lines, everything is razor sharp and I am not seeing any jailbars. (There's just a very minor little bit of color bleed on red, but that is mostly due to my RCA TV, red always bleeds a little even on my VCR. No other color has any bleeding at all.)

    I knew the Fujitsu MB3514 was a darn good encoder, but wow, I had no idea it could be this good. (All it took was an S-video connection...)
    Last edited by Eep386; 03-10-2018 at 03:08 PM.

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    WCPO Agent roadkill's Avatar
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    Quote Originally Posted by Eep386 View Post
    I just tried this on my MB3514-encoded VA2.3 (which I had modified to use a 47uH coil on L2 and tweaked up the band-pass filter and delay line to get a sharper composite image), and... uh..

    L-let's just have the picture speak for what this had wrought on my TV screen:
    IMG_0535.jpg

    My potato of a camera doesn't do this justice. It's way brighter and properly saturated in real life. In fact, it's damned near flawless. It looks very much like I'm playing this through RGB (which my TV lacks). There is almost zero color fringing, absolutely no pixellation or vertical lines, everything is razor sharp and I am not seeing any jailbars. (There's just a very minor little bit of color bleed on red, but that is mostly due to my RCA TV, red always bleeds a little even on my VCR. No other color has any bleeding at all.)

    I knew the Fujitsu MB3514 was a darn good encoder, but wow, I had no idea it could be this good. (All it took was an S-video connection...)
    That's fantastic and really excites me. I just recently got a VA1.8 for dirt cheap and it surprisingly has an MB3514 in it. I haven't modded it yet, but once I get a Mega Amp I'm going to add it as well S-Video mod my VA1.8 along w/ putting a stereo audio TRS output jack all in one sitting.

    I have tried out the composite video on it, and was shocked at how good it looked for a full motherboard Genesis Model 2, and I tested it before looking inside to see what video encoder it had.

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    Outrunner Eep386's Avatar
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    Go for it! I can't recommend S-Video modding the MB3514 enough.
    I've been playing with it for a few hours now. The picture quality is far better than I've ever seen, outside of an emulator. Yeah, I do miss the artifact colors of composite (the waterfalls in Castle of Illusion mainly) but that's a very small price to pay for such a dramatic increase in sharpness and reduction in cross-color interference.

    Later I'll try to get a CXA1645-fitted VA3 Model 2 and see if the jailbars and other crap problems goes away with S-Video on it as well.

    Update: Just S-video modded a VA2.3 with a CXA1645M, and it looks virtually indistinguishable from the MB3514 under S-video. Not able to find any VA3s with a CXA1645M, I just swapped one into a '1145M fitted VA3. We'll see how well the VA3 with '1645M handles S-video...

    Update 2: Yup, the VA3 MD2 with CXA1645M works perfect with S-video too, and picture quality is excellent, far better than its composite. No jailbars, pixellation, cross-color or any other composite nonsense. It looks just like the other CXA1645M and MB3514 with S-video. I'm beginning to think that S-video quality is pretty comparable between encoders.
    Last edited by Eep386; 03-12-2018 at 07:44 PM.

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    Outrunner Eep386's Avatar
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    Ok, here's a quick test video of my S-video modded MB3514 VA2.3 in action:


    It's a little darker than in real life because I'm still trying to figure out OBS's settings. On my CRT TV it's much brighter.
    The S-video does reveal some *slight* jailbars in the blue color, but they're extremely hard to make out and invisible most of the time.
    Last edited by Eep386; 03-21-2018 at 03:24 AM.

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    Outrunner Eep386's Avatar
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    Update, finally got around to S-video modding that CXA1645M like I said I would, and it works just fine
    There are still RGB-related jailbars in some colors, but all the other crap issues do indeed go away. S-video on CXA1645M is virtually identical to MB3514's except very slightly less saturated.

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