complete DUO S-Video mod

[nat]

And BTW, forum member D-Lite does TurboGrafx mods as a hobby. If you wanted to get your system "professionally" modded, he's the guy for the job.

[CkRtech]

I've actually talked via e-mail once before with D-Lite. I had some bad luck with the CXA1145 chip in my Model1 Genesis...

Hmmm....the Genesis uses a single composite sync that carries the combined Horizontal and Vertical Sync information rather than the separate sync info like the TG supplies. I assume these can be combined by tying them together - possibly with some resistors in the mix. Not certain.

Is that expansion connector a "standard connector" of any one type by chance? I don't have the TG16 yet. I look forward to getting it and investigating mod possibilities. That's quite a bit of useful signals on that expansion connector.

[nat]

Hmmm....the Genesis uses a single composite sync that carries the combined Horizontal and Vertical Sync information rather than the separate sync info like the TG supplies. I assume these can be combined by tying them together - possibly with some resistors in the mix. Not certain.

I think you can get the same result using just the VZ pin for sync and forgetting about VN, in that case. I'm sure D-Lite will correct me if I'm wrong but just VZ should be sufficient.

Is that expansion connector a "standard connector" of any one type by chance? I don't have the TG16 yet. I look forward to getting it and investigating mod possibilities. That's quite a bit of useful signals on that expansion connector.

Unfortunately, no. Not of any standard I've ever seen, anyway. I have extensive background in computer electronics and it's not used on anything else I've ever dealt with. As far as I know it's a proprietary connector.

The easiest way to tap signals off individual pins is to use an old SCSI/IDE ribbon cable and slice up the connector to effectively create single pin headers with a decent length wire attached. It's extremely easy to separate the wires on a ribbon cable. This is how I created my "custom" connectors.

[D-Lite]

I've actually talked via e-mail once before with D-Lite. I had some bad luck with the CXA1145 chip in my Model1 Genesis...

Hmmm....the Genesis uses a single composite sync that carries the combined Horizontal and Vertical Sync information rather than the separate sync info like the TG supplies. I assume these can be combined by tying them together - possibly with some resistors in the mix. Not certain.

Is that expansion connector a "standard connector" of any one type by chance? I don't have the TG16 yet. I look forward to getting it and investigating mod possibilities. That's quite a bit of useful signals on that expansion connector.

Nothing standard about the expansion port connector unfortunately.  Your best bet is to get a cheap Tennokoe Bank 2 or AV Booster and pirate the connector out of that. 

For the sync signal to input into the CXA chips, I've had much better results stripping sync from the composite video than tapping pin #44.  Seems to come through stronger.

Hope I was able to answer whatever questions you had with the Genny stuff back then.  If not shoot me another e-mail

[CkRtech]

Hey D-Lite, thanks for your input. Looks like pcenginefx has a really great community here.

So did you use an LM1881 to pull out your c-sync? Seems like it is a useful chip to have around.

Do you know what "state" the TG16 RGB circuit is in at the point it reaches the expansion connector? I know that all these video game consoles liked to put some components in the SCART cables rather than have each RGB output be ready to plug. The Genesis output needs a 75 ohm resister and 220 uf cap before it hits "standard" RGB output. My external converter most likely expects the signal to be "pre 75 / 220" as it plugs directly into the Genesis DIN port, so my experiment requires I essentially match the native RGB output of a Genesis in order to use the adapter.

Any thoughts?

[nat]

The Turbo's native RGB output straight off the expansion port should be roughly equivalent to that of the Genesis.

Check out this page for some more info about pulling RGB off the expansion port:

http://www.gamesx.com/rgbadd/duorgb.php

I see it mentions an amp near the end of the article that uses a 75 ohm resistor/220uf capacitor combo. You'd undoubtedly be just fine using the same setup you've got for the Genesis provided you can construct some kind of connector.

[CkRtech]

Oh awesome. Things are looking good so far...

[flooby]

Hey folks.  I finally found a "cheap" source of CXA1645 chips.  I bought a couple of broken PS1 consoles off ebay and am in the process of stripping the chips out of them.  Works out to be about $10 per chip.

Unfortunately, the first one is not going into the duo.  I'll let you folks know how it works using the RGB out from the Genesis.

[D-Lite]

Hey folks.  I finally found a "cheap" source of CXA1645 chips.  I bought a couple of broken PS1 consoles off ebay and am in the process of stripping the chips out of them.  Works out to be about $10 per chip.

Unfortunately, the first one is not going into the duo.  I'll let you folks know how it works using the RGB out from the Genesis.

Saturns too.  Actually, I think the Saturn has the 2075.  And the Genesis model 3 has the 1645 in it.

Passing the RGB through those chips is also a nice RGB amplifier for the Turbo systems.

[Michael Helgeson]

Both my Saturn first gen decks have the 1645 in them.

[Tatsujin]

are there any news or changes concerning the draft-schematic kspiff once did? would be great if this could be confirmed as 100% working

thanx a lot

[kid_rondeau]

are there any news or changes concerning the draft-schematic kspiff once did? would be great if this could be confirmed as 100% working

thanx a lot

Tatsujin,
I have built and can confirm the functionality of kspiff's schematic WITH THE EXCEPTION of pins 15 and 16 on the 1645...

On his schematic, he has pin 15 going to Y-out, and pin 16 going to C-out. But the circuit should be wired OPPOSITELY. (Although, interestingly, the pin numbers listed are correct, e.g.: Pin 15 does go to Pin 4 of the S-video socket, and Pin 16 does go to pin 3 of the S-video socket. They're just labeled backwards.)

In other words:
Pin 15 from the 1645 must go to C-out, and pin 16 must go to Y-out.

It's not his fault that he listed it incorrectly; Sony's product data sheet contradicts itself.


The only other difference between the way he listed it and the way I built it is the substitution of an EC1881 for the LM1881N, which is a direct drop-in replacement.


Other than that, I built it 100% true to the diagram, and I can confirm that it works.

[Tatsujin]

thanx a lot kid^^

shame on sony and its unproper documentation

as soon as i got the parts, i will start with it.

[CkRtech]

Has anyone thought about designing a board for this and getting it printed? It would certainly help keep things neat and tidy when putting the board together.

It may also be helpful to have a "video game S-Video" FAQ as it seems there are plenty of systems you can use that 1645 with. I don't know if there is a FAQ out there yet or not. ....maybe I'll write one. I would be very tempted to fill it full of anti-1145 propaganda, though. I can't stand that chip....

[Michael Helgeson]

Same here,I also cant stand the AD724,the favored chip of the Neobitz,useless piece of shit of the encoder world.