1-Chip with Tim Worthington's YPbPr Kit

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BONKERS
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Re: 1-Chip with Tim Worthington's YPbPr Kit

Post by BONKERS »

I am aware that the motherboards are different, but wouldn't it simply require finding the same points on a different revision to pull the RGB straight from the CPU?

Even you yourself mentioned
If you've tried this mod with any other version SNES, please let me know how you made out. Did it work? Did it improve the video quality?
And based on the schematic posted earlier
http://gamesx.com/wiki/lib/exe/fetch.ph ... _color.pdf

It looks like RGB is pulled from PPU-2 rather than the CPU
viletim
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Re: 1-Chip with Tim Worthington's YPbPr Kit

Post by viletim »

Skips wrote: With the older models cant you amp the rgb lines with a ths7314 then connect that to the component board? One ofthe 1-Chips I have is one I got cheap from a client who broke the rgb out legs off the encoder. I used a Ths7314 to restore RGB on it and connected the component board to the THS7314 before the resistors. I got the same results with it that I got with using the 1Chips's encoder on my other 1-Chip. In theory shouldnt the THS7314 work for these older models as well?
The THS7314 is not really suitable for something like this. It could be used, but would require a transistor stage before it, lots of resistors... It's probably easier to solder in a CXA1645 or BH7236AF actually.

Note that the video chip of the original Super Nintendo has some kind of slew rate limit on the rising edge of the RGB outputs. You're better off with the revised single chip version if you want good looking video.

See https://sd2snes.de/blog/archives/75
BONKERS
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Re: 1-Chip with Tim Worthington's YPbPr Kit

Post by BONKERS »

viletim wrote:
Skips wrote: With the older models cant you amp the rgb lines with a ths7314 then connect that to the component board? One ofthe 1-Chips I have is one I got cheap from a client who broke the rgb out legs off the encoder. I used a Ths7314 to restore RGB on it and connected the component board to the THS7314 before the resistors. I got the same results with it that I got with using the 1Chips's encoder on my other 1-Chip. In theory shouldnt the THS7314 work for these older models as well?
The THS7314 is not really suitable for something like this. It could be used, but would require a transistor stage before it, lots of resistors... It's probably easier to solder in a CXA1645 or BH7236AF actually.

Note that the video chip of the original Super Nintendo has some kind of slew rate limit on the rising edge of the RGB outputs. You're better off with the revised single chip version if you want good looking video.

See https://sd2snes.de/blog/archives/75
By video chip you mean the PPU? And does that mean that no matter what encoder you put in that sort of smeared 1px offset will always exist?
viletim
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Re: 1-Chip with Tim Worthington's YPbPr Kit

Post by viletim »

BONKERS wrote:By video chip you mean the PPU? And does that mean that no matter what encoder you put in that sort of smeared 1px offset will always exist?
Yes and yes.
BONKERS
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Re: 1-Chip with Tim Worthington's YPbPr Kit

Post by BONKERS »

Can a better encoder improve the other aspects of the video output in other ways though? You'd just have that 1px offset left?
(i'd be using this on a CRT)
I'd really like to get decent component out of my SNES without using a separate transcoder and scart. Getting a 1CHIP means dealing with the higher luminance levels. And it doesn't seem like anyone so far has had a concrete solution to that yet.

Also I've had this SNES my whole life. Guess I don't have any other choices huh? Or just deal with the softer output and use a transcoder.
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ApolloBoy
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Re: 1-Chip with Tim Worthington's YPbPr Kit

Post by ApolloBoy »

BONKERS wrote:Getting a 1CHIP means dealing with the higher luminance levels. And it doesn't seem like anyone so far has had a concrete solution to that yet.
Um yes there is, just sever the traces going to the RGB pins on the multiout, and then wire up 100~120 ohm resistors from the encoder to the appropriate pins on the multiout, just like modding an SNES mini. Problem solved.
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Pasky
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Re: 1-Chip with Tim Worthington's YPbPr Kit

Post by Pasky »

Or you could not destroy the traces and just replace the resistors already there assuming it's not a mini 1-Chip.
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RGB32E
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Re: 1-Chip with Tim Worthington's YPbPr Kit

Post by RGB32E »

ApolloBoy wrote:
BONKERS wrote:Getting a 1CHIP means dealing with the higher luminance levels. And it doesn't seem like anyone so far has had a concrete solution to that yet.
Um yes there is, just sever the traces going to the RGB pins on the multiout, and then wire up 100~120 ohm resistors from the encoder to the appropriate pins on the multiout, just like modding an SNES mini. Problem solved.
Has anyone even measured the levels at the multi-av output of 1CHIP-0x systems (non-mini)? I think there might be more than just a resistor on the RGB lines between encoder and the multi-av connector. I've compared a mini with 75 ohm resistors to a 1CHIP-01 and noticed that the mini appears brighter than the 1CHIP-01.

Tim proposed one idea in this thread for the mini to use 100 ohm resistors for the luma signal, and changing the N-C 75 ohm resistors to 100 ohm and calling that close enough. The other idea being to add 15 ohm resistors before the 75 ohm resistor to ground (voltage divider) on the RGB lines between the S-CPUN and the encoder to get proper levels on the encoder output so that no modifications to the N-C need to be made.

In any case there will be those who will never be satisfied with any solution from anyone (e.g. NES expansion audio, and using anything other than composite video). BONKERS, I'd suggest you save your concerns until you've installed and tried this kit. :P
RGB0b
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Re: 1-Chip with Tim Worthington's YPbPr Kit

Post by RGB0b »

RGB32E wrote:Has anyone even measured the levels at the multi-av output of 1CHIP-0x systems (non-mini)? I think there might be more than just a resistor on the RGB lines between encoder and the multi-av connector. I've compared a mini with 75 ohm resistors to a 1CHIP-01 and noticed that the mini appears brighter than the 1CHIP-01.

Tim proposed one idea in this thread for the mini to use 100 ohm resistors for the luma signal, and changing the N-C 75 ohm resistors to 100 ohm and calling that close enough. The other idea being to add 15 ohm resistors before the 75 ohm resistor to ground (voltage divider) on the RGB lines between the S-CPUN and the encoder to get proper levels on the encoder output so that no modifications to the N-C need to be made.

In any case there will be those who will never be satisfied with any solution from anyone (e.g. NES expansion audio, and using anything other than composite video). BONKERS, I'd suggest you save your concerns until you've installed and tried this kit. :P
Actually, Ultron on the Assemblergames forums measured the proper output of both 1CHIP and SNES Mini systems and was able to correct the THS7314 mod to output the exact brightness:

http://www.retrorgb.com/snes1chip.html#brightness

http://www.retrorgb.com/snesminirgbmod.html#brightness

As for using different output resistors, Calpis (also on assembler) kept trying to tell me that you're not supposed to use anything other then 75 ohm (for NTSC...150 ohm for PAL) on the output side of the THS7314, as it sends the wrong signal to the display. I actually contacted TI about that to double check, as I'd seen many people on this forum suggest using 100 (or 120 ohm) resistors instad of 75 ohm to lower the brightness. Calpis was right: Using the bigger resistors won't necessarily damage any equipment, but it could cause unwanted artifacts, since the signal isn't exactly up to PAL or NTSC spec. That being said, if you have a mod that uses the THS7314 and no one has tested the output with a scope (for example, with the N64), you can add resistors to the input side of the circuit. I use 75 ohm on both the input and output of my N64 mod's, but it's safe to go higher on the input side if needed.

BTW, I'm sorry for linking back to my own site, but the assemblergames fourm has been down for while. If the site ever comes back online, I'll try to copy the whole thread to PDF, just as an archive. Here's the link with all the details of Ultron's work, proving the correct levels, resistors, etc...assuming the thread is still there when the forum comes back:

http://www.assemblergames.com/forums/sh ... asurements
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Konsolkongen
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Re: 1-Chip with Tim Worthington's YPbPr Kit

Post by Konsolkongen »

RGB32E wrote: Just didn't find it to be a big deal with the XRGB-mini. I've discussed in the past of using a higher than 75 ohm resistor with the SNES mini, just not 100 ohms or greater. This being an example of 100 ohm resistors being used with a mini s-video mod:

Image
Not true. That's RGB with 100ohm resistors (as I didn't have 75ohm at the time). I took that picture using the screen capture program on the XRGB-3 :)
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RGB32E
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Re: 1-Chip with Tim Worthington's YPbPr Kit

Post by RGB32E »

Konsolkongen wrote:Not true. That's RGB with 100ohm resistors (as I didn't have 75ohm at the time). I took that picture using the screen capture program on the XRGB-3 :)
Whoops! :mrgreen: Yes, should have read RGB, not s-video... http://gamesx.com/wiki/doku.php?id=av:snes2rgb
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mikehaggar
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Re: 1-Chip with Tim Worthington's YPbPr Kit

Post by mikehaggar »

were all the kinks worked out for this? It seems to be a really good solution!

If so, are there any experienced modders that can do this mod for me for a good price (on a snes mini)?
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