Genesis Ver 2 video chip?

[Drewman21]

Just looking at add s-video to my genesis 2 and was looking for the video chip to tap off of.  I didn't see any that said sony on them like in other sega game systems.  I'm guessing the one chip i did find is one labeled  "SKA2195D" in the first line and "314" in the next one on the chip.  So no real luck on google for it.  I did find people who would mod Version 2 Genesis with s-video.  It does have 24 pins on the chip.  I know that the genesis 3 has the Sony CXA1645 chip which has 24 pins also.  Does anyone have a idea on the pin out for the SKA2195D chip?  Or even if it is the video chip for it?  I would love to have s-video for my Genesis 2.  Thanks for taking a look.
-Drewman21

[viletim]

s-video? that video format is obsolete now :)

In my Mega Drive 2 there's a Fujitsu video encoder chip (24 legs), I've got no info on it though. I suppose you'll need a cro to probe around with.

If you really want s-video you could always replace the encoder chip with a better one from sony or analog devices (you'll have to build a little circuit for it).

[Akir]

Just a factiod: S-video was outdated when it came out, because RGB came out first (and we all know that it's better then any other video format except digital).

[Drewman21]

Wow! That was a great factoid.  And it would be great if I lived in europe or if i wanted to buy a small ass RGB monitor and make my own cable for it.  I realize RGB rules and that it is all great and it needed to be said once again. BUT, my question was if anyone had a idea on the Genesis version 2's video chip. Just wanted to know that so I could maybe spend like 5 bucks on parts and play with a silghtly better video image on a 30' TV and not worry about how in the hell to screw around with RGB.

Thanks for the opinion but I was looking for something closer to fact.

-Drewman

Edit:  I would like at least thank viletim for a suggestion for something to try in response to my question.  I don't mind a little ribbing about a supposed "dead" or "obsolete" tech as long as your willing to give a hand and help out. <_<   Danka

[phreak97]

the video chip on the genesis2 is the surface mount chip on the top of the pcb closest to the av jack. i have heard it is pin compatable with the cxa chips, but my attempt to switch it from pal to ntsc in my md2 failed where i did it successfully in my md1 on the cxa chip, so i cannot vouch for this so called compatability.

[viletim!]

Today I had a look inside my Mega Drive 2 - here's what I found:

It employs a MB3514 video encoder IC, made by Fujitsu. This chip seems to be a drop-in replacement for the sony CXA1645 and does have outputs for s-video that are capable of driving a 75 ohm load (ie. a tv or monitor). Pin 15 is chrominance and pin 16 is luminance. If it helps anyone, pin 15 is connected to R56 (1k2) and pin 16 is connected to R47 (12k).

to make the signals s-video compatible a resistor and cap are required on each line

Code Select Expand

.                      | |
. chroma o----/\/\/----| |-----o
. pin 15       75     +| | 220�
.                                 out to
.                      | |        monitor
. luma   o----/\/\/----| |-----o
. pin 16       75     +| | 220�

Also worth mentioning is that the RGB signals output from the big 208 pin sega chip have an amplitude of about 5vpp. They are reduced by a potiential divider before being fed to the encoder chip. If anyone wants to connect one of these to an arcade monitor then tap into these signals, they are just what the monitor likes. The video comes out of pins 35, 36 and 37 though I'm not sure which one is which.

Drewman21,
Any idea who makes that SKA chip? Look up the logo here

Akir,
That's not really true. The s-video input for TVs was designed to be a high quality video input for SVHS VCRs. Not many people bought SVHS VCRs (dunno why, they were pretty good) and now they're no longer made. Now there aren't really any consumer AV devices the market that wouldn't benifit from outputing either RGB or colour difference video except for the standard VHS VCR which is happy with composite video. So that's why I say s-video, from a techincal standpoint, is obsolete. Of corse in the real world it's as popular as ever...

[Lost Monkey]

Here is a pic of the SKA2195D... there is no logo...

I have 5 Gen 2's and they all have this chip.. they all also (coincidentally) have the blocky looking composite out which my Gen 1 (Sony CX) does not...

[viletim!]

good photo...
SKA? No! That's KA2195D, a Samsung chip. A data sheet wasn't too hard to find.

This chip looks to be a cheaper (crappier?) alternative to sony's chip. It's pin compattible with it but not functionaly identical - it uses a lot less external parts and it DOESN'T OUTPUT S-VIDEO. It's limited to NTSC output too.

All hope is not lost however...If you're keen you could remove this inferior encoder chip (cut it off with side cutters then desolder each leg individualy) and put a decent sony chip in it's place. You'll also have to fill in the missing components as well, shouldn't be too hard.

[Drewman21]

Wow!  I would like to thank all of you for your help on this.  I was trying to get my pic of the chip posted but the g/f wouldn't give up the webspace to host it. My bad. Oh well.  Taking a look at what you guys dug up on the chip I think that I will dig up a sony chip and replace the old one.  If it tap off the output of the chip what else will I need?  Or are you saying that there are components needed to change the input in to the replacement sony chip to let it output S-video?

Thanks again!
-Drewman21

[viletim!]

Drewman21,
If it's just s-video you're after then simply replace the chip and take the output from pins 15 and 16 (through the cap + resistor). And you're done...in theory. Composite video output will no longer work due to the missing components required by the sony chip to make it.

[Lost Monkey]

good photo...
SKA? No! That's KA2195D, a Samsung chip. A data sheet wasn't too hard to find.

Thanks for the info, I'll give up on the Gen 2 S-video and just keep the Gen 1...