Console s-video mods (Genesis & PC-engine)

[Rassilon]

Hey gang,

I've got a genesis model 2, a pc-engine core grafx and a turbo-duo (US), and i want to add s-video output to them. (i know component is best, but the higher cost and hassle in my setup outweighs the benefits for now).

I was going to go with the neobitz DIY s-video board, but i've read that the neobitz doesnt get along with the genesis..

Whats the best way to get s-video out on the genny? JROK?

for the pc-engine/turbo-duo, are there any problems with using a neobitz or jrok?

anything else i'd need or any advice/suggestions for getting the best s-video out on these babies?

Thanks!

 

[DewmanSNK]

Ahh the JROK vs NeoBitz debate.

Because you are not using it with a mvs I would say JROK, as a JROK owner I may be biased. I have heard of compatibility issues with non MVS hardware when using the Neobitz. I cant speak from experience with the Neobitz, but I love my JROK. I got the sync cleaner as well for $15, and have used that and the 4.1 board on a dozen different PCBs as well as a 2 and 1 slot MV-xF.

As far as pinouts, look to dubdubdub.gamesx.com (Avoiding the direct link)

 

[Xian Xi]

Double check the internal encoders on the consoles you want to mod. Most encoders offer both composite and s-video but dur to mainstream demand only the composite was utilized. The pins the pull s-video from the internal encoder are most likely there. In some cases like a genesis you may need to build a very small and simple circuit for the s-video to work properly, usually just caps and resistors.

 

[Hewitson]

The Megadrive does already (internally) output S-Video, refer to the encoders datasheet for information on recommended caps/resistors.

 

[Logicdustbin]

The model 2, I believe, had 3 different revisions of video chips, 2 of the revs could be modded, the 3rd one could not.

I have about 15 module 2 genny's in my basement that cannot be modded....but that version might be most common up here in Canada...

 

[Hewitson]

Can you tell me which encoder they use if possible?

 

[Rassilon]

Thanks for the info guys!

How can i tell if my genesis has the vid chip that can get s-video out? My genny is on the way from ebay right now, but i will check when it gets here.

And where can i get the info on the circuit diagram and caps/etc i need?
I looked around on gamesx, but didnt see anything (i didnt dive into the forums yet...)

Thanks!

 

[Xian Xi]

Model 1 and 3 can be modded from internal encoders.

Model 1 = Big Genesis
http://www.computercloset.org/SegaGenesis1.jpg

Model 2 = Med Genesis
http://www.old-computers.com/museum/photos/sega_genesis2_1.jpg

Model 3 = Small Genesis
http://upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Sega_Genesis_3.jpg/800px-Sega_Genesis_3.jpg

 

[Rassilon]

OK, i got my genesis today (model 2), and took it apart to check the video encoder.
The chip that i think is the video is a KA2195D (samsung?).
It seems that the desired chip is a CXA...

What are my options on this? a j-rok? or try to get a genesis with the sony cxa chip?

 

[Rassilon]

OK, after several trips to all of the used game shops around here, i picked up two more genesis consoles.
Got a model 1 with the CXA1145 and a late revision model 2 that has the CXA1645 encoder.
Gonna use the model 2, which i can pull s-vid straight off the chip (with a resistor and cap), instead of the buffer needed on the 1145 (plus i wont have to mess around to pull stereo audio from the headphone circuit like i would on the model 1).

How about the pc-engine?
I have a gore grafx and a US turbo-duo i want to mod...
I'm hearing now that the jrok s-vid board doesnt play nicely with pc-engines. anyone try the neobitz board?
Build my own with a CXA1645 chip?
what are my options on these?

Cheers!