Does NES have an A/V Pass-through?

JackFrost22 · Post by **JackFrost22** » Thu Dec 09, 2004 5:19 pm

option twos kinda hard

SgtBowhack · Post by **SgtBowhack** » Fri Dec 10, 2004 9:22 am

But not really. I mean, it's basically "When a button is pressed, set a pin of the cartridge output high. Oh, and output no graphics please. Thanks."

MM007 · Post by **MM007** » Fri Dec 10, 2004 1:51 pm

SgtBowhack wrote:But not really. I mean, it's basically "When a button is pressed, set a pin of the cartridge output high. Oh, and output no graphics please. Thanks."

I guess my next questions would be this:

I know the Atari gets composite video by connecting Luma and Chroma.

Should I connect Luma and Chroma to get composite(I hear it sometimes causes problems on some monitors), or does the NES have Luma and Chroma pins as well?

If it is the former, do you forsee any problems getting it to work with the NES?

Finally, will this in any way reduce my ability to use the NES with an RF adapter?

SgtBowhack · Post by **SgtBowhack** » Fri Dec 10, 2004 5:26 pm

Errrr... connecting Luma and Chroma are the only way to get Composite video. So, yes, you should connect them

You may need to use a cap in there, as the info on this page shows: S-vid to composite
Unless the Atari already does this, in which case, you just pull from the composite area.

It will not affect the NES video at all, but it also won't send the Atari video up into the NES. To use only one set of video cables, you'd need to send all video through your Atari box under the NES. I'd suggest using a DPDT switch for the composite video and audio that's going into the Atari's RF modulator too (involving breaking some traces):

Code: Select all

AtariV  ToModulatorV NES-V
   o         o         o
   o         o         o
AtariA  ToModulatorA NES-A

Though you'll have to make sure(!) that Atari and NES ground are connected to do so. I think you might be able to get away with a making a splitter for the power supply connector of the NES, and connecting one end to your little Atari box and one end to the NES, thus making sure ground is one and the same without making internal connections (though making those connections probably wouldn't hurt).

In short, yes, you can't use your NES RF switch unless you make your Atari box support the NES video through that sort of switch. You may want to include a video and power switch on the front of the box, since the NES shouldn't really need to be on when the Atari is. Or, actually, you can simply switch where the power is plugged into by the method of your choosing, since you can't play Atari and NES at the same time. You wouldn't need a power supply splitter cable then, nor would you need the DPDT switch mentioned above. So, erm, just take those as ideas in case you really decide you want it that way.

HK-47 · Post by **HK-47** » Fri Dec 10, 2004 5:30 pm

Heres the link: S-vid to composite

SgtBowhack · Post by **SgtBowhack** » Fri Dec 10, 2004 6:03 pm

Ah crap, sorry, put it without the / in the close brackets.

HK-47 · Post by **HK-47** » Fri Dec 10, 2004 6:13 pm

There you go...

MM007 · Post by **MM007** » Fri Dec 10, 2004 8:58 pm

Okay, thanks! ^^