Snes jr. with a cxa2075

Drakon · **Posted:** Fri Jan 27, 2012 5:33 am

Since I was so impressed wtih the cxa2075 in my sega genesis making the picture quality much sharper than the cxa1645 I decided to try wiring the 2075 into my snes jr. Sure enough....the s-video picture quality is an improvement over the encoder built into the snes jr. So I tapped the rgb, sync, and colour subcarrier inputs of the encoder built into the snes. Don't worry the original encoder is still in the snes jr. and it still works great. I have s-video wired into the s-video output from my cxa2075 circuit:

Here's a screenshot

The screenshot looks a little messy but believe me the picture is definitely sharper than it was before. My capture card just picks up strange things that don't show up at all on my crt tv.

ShockSlayer · **Posted:** Fri Jan 27, 2012 6:58 am

Boss.

Drakon · **Posted:** Fri Jan 27, 2012 7:47 am

ShockSlayer wrote:

Boss.

Thanks! It means a lot to get such nice comments from such a great modder like yourself.

Screenshots comparing the s-video from an un-modded snes model 1 vs. the s-video from my snes jr. with a cxa2075 installed.

ShockSlayer · **Posted:** Fri Jan 27, 2012 8:02 am

Definitely looks crisper to me.

Drakon · **Posted:** Fri Jan 27, 2012 8:09 am

ShockSlayer wrote:

Definitely looks crisper to me.

The video encoder that's built into the snes jr. is also crisper looking than the model 1, it's about the same as a cxa1645. But the cxa2075 is definitely crisper than the cxa1645.

thelukestir · **Joined:** Wed Nov 04, 2009 5:07 pm **Posts:** 217

win, want to get a couple of these for myself 8)

Drakon · **Posted:** Sun Jan 29, 2012 7:21 am

PM me for a commission. Or if you're good at modding yourself it isn't too difficult really. All you need to do is pick up a cxa2075 chip. Then you need to buy a sop to dip adapter for it. Then solder it into the adapter and solder the adapter into a precision socket or a breadboard. Then solder up the ntsc internal trap application circuit from the cxa2075 datasheet. I used this pinout sheet to find out where to tap r, g, b, sync, and colour subcarrier from the encoder that's built into the snes jr.

Then you just wire everything up and assuming you wired and built things right you're good to go. Another note...using a 75 ohm resistors on the luma output was a little dark so I used a little less resistance than that. Also the snes jr has an issue with the chroma line I use a 470 ohm resistor on the chroma line before passing it through the 220 uf cap otherwise you get diagonal bars on chroma. Don't worry using 470 ohms doesn't weaken the chroma line.

XCVG · **Posted:** Mon Jan 30, 2012 5:33 pm

Where did you find the CXA2075? I can't even find a datasheet

Drakon · **Posted:** Tue Jan 31, 2012 5:03 am

XCVG wrote:

Where did you find the CXA2075? I can't even find a datasheet

ebay link after I typed in "cxa2075"

http://www.ebay.com/itm/SONY-Encoder-IC-Converts-IC-CXA2075-CXA2075M-NEW-/250369826117?pt=LH_DefaultDomain_0&hash=item3a4b345d45

Try the alldatasheet link. It's the first thing that comes up when you type "cxa2075 datasheet" into google...

Hydrobradman · **Joined:** Fri Jan 27, 2012 7:22 am **Posts:** 7

Wow, it looks a lot sharper and the contrast is vastly improved. It almost seems a bit too sharp?

Snes jr. with a cxa2075

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