Sync on N64 Rev-04

So I just performed the RGB mod on my NTSC N64 Rev-04. For sync I ended up connecting pin 7 luma to pin 9 composite (with a 75 ohm resistor in between) and then cut the trace on pin 9.

It goes from the scart cable to an upscaler/converter and then from there, HDMI to my NTSC led TV.

I'm stuck with "No signal" constantly. I've checked, rechecked, and have redone many of my soldering connections just to ensure that wasn't an issue. I even disconnected my amplifier entirely and just went straight RGB to the multi-out and still "no signal". When I try composite though it plays fine in black and white (which should mean that just luma is coming through). I'm thinking now that it's an issue with sync.

I purchased a "Raw" SNES scart cable from retro console accessories. However, I am not sure what "raw" means. Does this mean that the cable pulls sync from the sync pin 3 on N64's Multi Out instead of the composite pin? Should I just bridge pin 7 luma with pin 3 sync instead if this is the case?

Any info anyone has would be greatly appreciated!

 

Raw sync cable means that it gets it's sync signal from the pin marked S in this picture:


So thats why you don't get any signal.

 

Gotcha, that was my suspicion, thank you for the quick reply! I will bridge 7 to 3 instead and see if that solves my issues.

 

Yep that did the trick and RGB looks damn good!

One more question though, seeing as how I didn't need to cut the composite trace after all... Does anyone know what pin/hole under the board carries the composite video signal? It would be cool to patch that back in so I am able to switch back to composite from time to time just to admire how much better RGB is, haha.

 

Yellow marker is the composite video signal

 

You rock man, thank you.

 

I have the same exact setup, and have the same issue. I added a 75ohm resistor between pin 3 & 7 but I still get no signal or sound. Also when I turn on the console and test pin 16 on the SCART connector I get 0v. Is there something wrong with the mod/amp?

 

For C-Sync you can use either composite or luma, luma is liable to give a better image as it is B&W whereas composite also contains the colour (chroma). To get the correct brightness of the image, ie dim the picture; don't use 75ohm as that is far too dark (which will be obvious in dark games like Doom64) - Nintendo use 38ohm in their cables for this so is therefore correct as they do it; put two 75ohm resistors in parallel (to get around 36ohm) - connect one end to ground and the other end to the luma pin; and obviously connect your C-sync to the luma connection then.

 

Thank you for the response, but the issue I'm having is that I get nothing to display on the tv. I get no audio or video through SCART, but through composite I get audio and video.

 

You need to feed SCART with voltage, pin 16 needs 1-3 volts otherwise it isn't in RGB mode.

I made an easy diagram to follow, many on the net aren't.

http://www.bacman.co.uk/home/scart/

 

What Bacteria said and also, don't use Composite video or Luma as Sync. You can tap true C-Sync from the console's U4 chip. It will give a better picture than Sync-on-Luma or Sync on composite video. Also, find a way to power pin 8 on the SCART plug with 12V. This will force the converter to display the signal in a 4:3 aspect ratio. It may look better with some games.

 

does the 1-3 volts for pin 16 come from the amp? I read your diagram but it just shows the pinout.

Do you have a diagram on how to tap the c-sync form U4 as well as how to power pin 8? is it a direct connection or should I put a resistor in line?

 

You can get 1-3V by using a 75ohm, 100 ohm, or 180 ohm resistor between pin 16 on the SCART plug and the +5V coming from the console. To get +12V on an NTSC system, you will have to use an external PSU that sends +12V directly to pin 8 of the SCART plug. Only PAL consoles have +12V on pin 3 of the multi-out, which is C-Sync on NTSC systems.

Getting C-Sync depends on the video chip (should be the U4 chip). If you have a DENC-NUS chip, it's pin 15. If you have a VDC-NUS chip, it's pin 14. If you have a AVDC-NUS or an MAV-NUS, you will need to install Tim Worthington's N64RGB board to get C-Sync. If it doesn't work, try connecting one leg of a 680k resistor to the chip then the other leg to a wire leading to pin 3 of the Multi-Out.

 

This is what I understand for 1-3 volts:
open the SCART connector and using a multi meter place one probe on the +5v of the multi-out and using the other see which pin it is on the SCART connector. Then using a resistor jump pin 16 to that pin. Correct?

Do i have to remove the resistor on the multi-out between pin 3 and pin 7?

I read that the on the rev-04 boards the sync components are not installed (to save money i guess) so just jumping pin 14 of U4 to pin 3 is enough?

sorry for so many questions.

 

It's ok to ask many questions. Remove the resistor between pin 3 and 7. For the SCART plug, the cable you bought already has the resistor for pin 16 so don't change it. It is jumped from pin 8 though, which is being fed +5V in that cable. It would be much easier to just manually change the aspect ratio to 4:3 with the TV's remote. The SCART plug has the pins labelled on the outside where the pins are.

Don't just jump pin 14, check your U4 chip model number first. It is printed on top of the chip. If it is a VDC-NUS, then C-Sync is pin 14. If you don't have a VDC-NUS U4 chip, check here to see where C-Sync is on your chip. This guide is for a NUS-CPU-03 board with the VDC-NUS U4 chip but should show you how to wire it up.

You need a 680k resistor or you won't get a picture. Simply wire the resistor to the C-Sync on the U4 chip (differs by model number). Next, solder one end of a wire to the resistor then solder the other end of the wire to pin 3 of the Multi-Out. You should get C-Sync after this.

 

Will manually changing the aspect ratio get me picture? or is it because I don't have C-sync I don't get picture? my U4 is VDC-NUS so I will try and follow the guide you posted. also like I said when I checked pin 16 on the SCART connector it was at 0v?

 

No it will not give you a picture. The aspect ratio is just whether or not it's widescreen (16:9) or pan and scan (4:3). Some N64 games looked stretched when in 16:9 so that's why I mentioned it. Sorry for the confusion.

It will say 0V because there is no power coming through it. You need the system on when checking for power lol. I have the composite video as sync version of the cable you bought from the same seller. You don't need to make any changes to the cable. The problem is within the console itself.

Since you have the VDC-NUS, just do the 680k resistor and wire from pin 14 on the chip to pin 3 on the multi-out and you should be good to go. Make sure to remove the resistor between Multi-Out Pin 7 (Luma) and Pin 3 (C-Sync for NTSC consoles, +12V for PAL consoles) first.

 

Thanks for the reply MonkeyBoyJoey, the console was powered on when I tested pin 16, but just to clarify my SCART Cable is from ebay. it came with the HDMI converter I bought. and the reason why I tried the resistor on pin 3 and pin 7 is because I believe it is "raw sync" is there any way of telling from the connector what type of sync it is?

 

Yes there is a way. If you get continuity between Pin 7 (console plug) and Pin 20 (SCART plug), it's sync-on-luma. If you get it with pin 9 (console plug) and pin 20 (SCART plug), it's sync on composite video. If you get continuity with Pin 3 (console plug) and Pin 20 (SCART plug), it's C-Sync. To make testing this much easier, plug the cable into the console and use the pins on the Multi-Out for testing continuity.

Raw sync is a cable wired for C-Sync as the sync source. Can you measure how many volts pin 10 on the Multi-Out is getting? If it is outputting +5V, then your cable doesn't have a 75 ohm, 100 ohm, or 180 ohm resistor connecting the wire from that pin to 16. Also if you haven't already, open the SCART connector by untwisting the plastic piece where the cable meets the plug. After that, carefully open the SCART plug. Do not apply too much force as you could break it. It should be a snap-together kind of plug.

 

so plug the SCART cable in and then test pin 10 on the multi-out?

which kind of sync does the cable have to be to work properly?

which kind of sync is needed for adding the 680ohm resistor to pin 14 of U4 to pin 3 of the multi-out?

so to enable RGB mode I need 5v from pin 10 of multi-out to pin 16 of SCART?