New RGB to Component converter design using the BA7230LS

[Ace]

Lastcallhall and myself have messed around a bit with the ROHM BA7230LS in an effort to make an RGB to Component converter on the same quality level as my previous BA6592F-based converter, but that's easier to build.

Unfortunately for Lastcallhall, he wasn't able to get anything working, and at first, I had issues, too. It took some work, but I got a working converter put together using the BA7230LS. A few tweaks needed to be made as this chip has some differences compared to the BA6592F:

1) The Component outputs seem a little weaker than on the BA6592F, requiring more amplification of each signal.
2) Although there's a Composite Sync input on the chip, it doesn't mix the Sync with Luminance unless you feed it back into the chip. Because of this, mixing of Composite Sync directly into Luminance is required.

The result with the BA7230LS is nothing short of amazing. Here's a preview shot of Daytona USA running on the Saturn via my new converter:



This is better than anything I got out of the BA6592F. Whereas that chip induced cooler colors, the BA7230LS preserves the color temperature of the RGB source, so if your RGB source has very warm and saturated colors, you will get those same colors in Component.

And now, the schematic, which I've attached to the post. I can confirm the circuit working on the following consoles:

-Saturn
-Genesis Model 1 (VA2 motherboard tested, but all Genesis Model 1s should work with the circuit)
-RGB-modded PC Engine Duo-R

I encourage others to test this circuit on other consoles and report back.

EDIT: CIRCUIT UPDATED TO VERSION 5.0.

Click here for the new circuit.

[evildragon]

Can you please upload the money shot on something other than Imageshack please? I really hate that site, and their inability to just get right to the full image, and countless popups.

Photobucket is much better for direct links and no popups. (Still has ads but no popups or popunder ads).

[Flygon]

Can you please upload the money shot on something other than Imageshack please? I really hate that site, and their inability to just get right to the full image, and countless popups.

Here, have a hotlink.

[Lastcallhall]

It was the c-sync. It works beautifully now.

[evildragon]

Here, have a hotlink.

Thanks, I wish people linked like this more often. I had no idea imageshack even allowed a link like that.

[lumclaw]

Dang. Bunch of systems here this might be useful for. Too bad it's so expensive to have a modder work in bulk. Not to mention packing multiple consoles...

[Drakon]

I looked up the datasheet of this chip it has a "sync in" pin which you're not using, any particular reason why? Would using that pin eliminate the need to mix sync with the y output pin?

[Ace]

I guess you missed this bit:

2) Although there's a Composite Sync input on the chip, it doesn't mix the Sync with Luminance unless you feed it back into the chip.

If you wire up Composite Sync to its respective pin on the BA7230LS, you'll get a desynced picture. As the block diagram in the datasheet shows, the Luminance output has no Composite Sync mixed in from inside the chip, so you have to mix it externally yourself.

[Drakon]

Oh okay, thanks for pointing that out.

[marvelus10]

If you could sell me with a BA7230LS and a 2.2k resistor I would love to try this with my CMVS I'm building. I seem to have all the rest of the parts.

[lumclaw]

I'd probably buy a few assembled kits for the right price and video quality.

[Lastcallhall]

I don't know about Ace, but I'm waiting on China for parts. Apparently, it's a holiday that lasts a week over there, so I won't get anything shipped to me until Oct. 8th at the earliest. Once I get them, I'll see about making kits for sale. I'm also toying with the idea of a PCB, with Ace's input and assistance, of course. I already made one for the BA6592F, so it should just be a matter of tweaking the PCB file to fit the S-ZIP chip and swapping out the resistors for potentiometers on the P-R and P-B outs to allow a bit of customization to the chip.

[Ace]

Don't forget POTs on the RGB inputs.

Now, I was thinking of making some pre-assembled RGB to Component converters with the rest of the BA7230LSes I have and selling those off. I don't have a PCB design to use, but once I get a PCB design for the different variants of the box, I will be taking custom orders and making a price for the boxes. I will make boxes with the following options:

-RGB input type: SCART connector (with optional audio pass-though), DB9 with Commodore 1084S pinout plus optional RCA jacks or 3.5mm headphone jack for audio, separate RCA jacks for RGB, Sync and audio (audio input could also be a headphone jack)
-Component output type: RCA jacks for Y/Pb/Pr and audio (or a headphone jack for audio), DB9 or VGA connector with custom cable for all outputs

I'm hoping to build boxes which will sell around the $30US mark, but as I will supply a DC 5V power supply and Component cables with each box (you will have to provide your own RGB cables), it may be a bit difficult as those might cost more to get than the box itself.

[lumclaw]

Cool I didn't think of that. A nicely enclosed box will be way cheaper and easier overall. Then it'll work with a SCART selector instead of having to buy/install a kit per console.

Then again I own some CSY-2100 type device which already does what I've just described. So video quality improvement would need to be the selling point. Of course audio input/output jacks are an upgrade over mine too!

Parts+labor+postage to have some modder add component to my SMS, SNES, Saturn, PS1, etc, is sticker shock. o_o

[Lastcallhall]

Don't forget POTs on the RGB inputs.

Now, I was thinking of making some pre-assembled RGB to Component converters with the rest of the BA7230LSes I have and selling those off. I don't have a PCB design to use, but once I get a PCB design for the different variants of the box, I will be taking custom orders and making a price for the boxes. I will make boxes with the following options:

-RGB input type: SCART connector (with optional audio pass-though), DB9 with Commodore 1084S pinout plus optional RCA jacks or 3.5mm headphone jack for audio, separate RCA jacks for RGB, Sync and audio (audio input could also be a headphone jack)
-Component output type: RCA jacks for Y/Pb/Pr and audio (or a headphone jack for audio), DB9 or VGA connector with custom cable for all outputs

I'm hoping to build boxes which will sell around the $30US mark, but as I will supply a DC 5V power supply and Component cables with each box (you will have to provide your own RGB cables), it may be a bit difficult as those might cost more to get than the box itself.

Cool, I think you and I are on the same page here. As soon as I get those parts in, we'll go over the fine details.

Also, do you really think we need fine tuning on the ins and outs? Just curious.