January 30, 2018 at 10:13 AM #18846
Hi, with the OSSC on its way, I am a bit worried about whether my N64 setup will work.
I bought my Japanese RGB modded N64 on eBay here: https://www.ebay.com/itm/Nintendo64-N64-RGB-US-JP-NTSC-model/202209466974?hash=item2f149f9a5e:g:SOkAAOSw9V1ab-u9
I was hoping someone could tell me what kind of RGB mod this is (pic: https://imgur.com/a/tWGH0), and if I will encounter any issues using the official PAL RGB GameCube cable from Nintendo (I also use this for the Super Famicom, and the cable works on both consoles perfectly when plugged straight into the SCART input of the TV). I couldn’t find the technical specs of this specific cable. Would you recommend using another cable?January 30, 2018 at 12:43 PM #18852
I’m certainly not an expert, but for all RGB mods for the N64 I would recommend the SFC SCART cable, as the PAL cable is wired differently, and if you use it, you could fry your equipment.
With regards to that mod, I’ve never seen that particular circuit board before, but it’s a standard THS7314 mod it looks like, and not a very good one. If you look at the board, he has terminated the outputs with 75 Ohms, which is correct, but not necessary if your SCART cable already has 75 Ohm resistors in it. I’ve also noticed he’s jumped the capacitor terminals on two of the colour outputs, whilst leaving the third colour with its capacitor in place. These capacitors are all components usually present in your SCART cable, the only way to know for sure is to open it and have a look. Also, the eBay listing says his consoles are wired for CSYNC, but there is nowhere for the CSYNC to run on his circuit board. The likelihood is he is using older Japanese models that have TTL sync already hooked up to the multi out, but without proper attenuation via a 470 Ohm resistor in the SCART cable, you again risk damaging your equipment. My advice? DO NOT plug that wonky N64 into your OSSC via any means, the shoddy workmanship may damage either your N64, your OSSC, or both.January 30, 2018 at 11:10 PM #18860
The board looks fine to me. 75 Ohm on the outputs is correct for an NTSC console. All three capacitors C4,C5,C6 of the color outputs are bypassed as they should be. The big capacitor on there is likely a 100uF power filter. It is next to a smd cap and the schematics of the 7314 recommend a 0.1uF and a 100uF capacitor between power and ground.
TTL CSYNC out of the multi-out is also correct. All NTSC SNES and N64 CSYNC RGB cables should have a 330-470 Ohm resistor on the CSYNC line.
An official PAL RGB Gamecube cable uses composite video for sync and it has a 75 Ohm resistor to ground and a 220uF capacitor on the sync line. Composite video sync and luma sync cables with NTSC consoles should have no components on the sync line. As your Super Famicom also works with the cable it may work with the N64 too. The only thing that can happen is that you can get unstable sync because the resistor on the sync line lowers the voltage. As long as it works it is safe to use with the OSSC.
If you have sync issues or see diagonal interference in the image then its best to use a NTSC luma sync RGB cable.January 31, 2018 at 10:38 AM #18864
Thanks for the help! Just to be clear, the official RGB cable for the GameCube works perfectly on my Super Famicom (regular version, not 1CHIP) and my modded NTSC N64 (the one posted above). Also the guy from eBay has been doing doing the RGB N64 mod for more than 7 years. If there was anything wrong with it, I’d think he’d have figured it out by now (I hope). Will look into buying the NTSC luma sync RGB cable if I face any issues.
I’ll get back to you once I get my OSSC, and will post the results.January 31, 2018 at 12:41 PM #18865
Where in the world are you based? We can recommend cable vendors to you based on that. You can use a CSYNC cable with the N64, as the other poster mentioned, you need to have a 470R resistor followed by a 220uf cap on the line to correctly attenuate the signal.January 31, 2018 at 1:02 PM #18866
I’m located in the Netherlands. So based on what exactly should I get the CSYNC or Sync on Luma cable, since they both seem to work?January 31, 2018 at 3:20 PM #18875
If you get a properly-shielded cable, I believe sync-on-composite is the most correct/normal type of cable to get, otherwise sync-on-luma. Csync really isn’t needed unless you’re using a PVM/BVM that really doesn’t like sync-on-composite/luma, and it’s not needed at all if you’re using something like the gscartsw_lite (which has a sync-stripper built-in) or any other SCART-capable equipment (which basically expects sync-on-composite[/luma?] because that’s how it’s been done for years).
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