Subject: Re: [TI994A] Re: Analog RGB to Svideo or VGA conversion

From: [email-masked]
Date: Thu, 17 Feb 2011 17:34:10 -0600 (CST)

Guess I missed this, yes, I'm interested. :)

On 02/10/11, Tony Knerr<[email-masked]> wrote:Another update, good news!

I added the LM1881 sync cleaner to the Neobitz board today.
A couple of capacitors, a resistor, and 2 jumpers are also necessary.
Also found a problem with the board layout, as pins 6 & 7 for the
LM1881 are reversed, easily solved.

The component video output is quite clear. I would say it's 90% as
clear as RGB, based on the S-video output being 75%. All in all a
quite good investment for the result. I still need to get 3 pots to
add to the circuit to see what the proper resistance for the RBG
inputs on the board should be, but that's a minor matter.

I asked the designer of the board if he could build some for us to
the specs required for the Geneve or other 9938 TI devices, and am
waiting to hear back from him. Worst case is I could buy stock boards
from him and modify them for our uses, or you guys could do it yourselves.

Anyone interested?

Tony

--- In [email-masked], "Tony Knerr" <tonyknerr@...> wrote:
>
> Ok, here's an update.
>
> I got the Neobitz board today.
> http://neobitz.com/Pages/Mods/SystemMods.aspx
>
> Hooked it up to a Geneve and a 15" LCD monitor via component inputs
> and - nuthin'!
>
> So I tried the composite output, and got a funny looking screen with
> the wrong colors, but it was viewable.
>
> Did some research, the Neobitz board accepts negative composite sync,
> the V9938 outputs positive composite sync (Thanks, Bob!)
> Found this:
> http://www.twobits.com/RGB/sync.html
> So I desoldered a 74LS04 out of a dead TI, and Voila! I've got an
> acceptable output on the composite and S-Video outputs of the
> Neobitz.
>
> The component connection still doesn't work, though. I'm guessing it
> needs a 'sync cleaner' added to the board. I'm waiting to hear back
> from the developer of the board on that point, seems like a good
> guy, hopefully this will work out.
>
> The S-Video output is not bad, it's actually fairly clear, and will
> be acceptable if no solution is forthcoming on the component output
> problem.
>
> I'll keep you posted.
>
> Tony
>

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