N64 RGB Mod - Poor quality image

[fathertime]

maybe someone can help..

I have a first edition USA N64 modded for RGB and used on a PAL TV that supports 60hz NTSC RGB.


The problem is
-horrible horizontal lines on the top 1/3 of the screen that "flicker"
-a X pattern through all the graphics.
Have a look at the attached image.


I modded this almost 15 years ago - It's modded with the same method as per mmmonkeys RGB "Method 2" on this page http://www.mmmonkey.co.uk/console/ni...ndo_64_rgb.htm

For the RGB cable, I've tried both my custom PAL SNES RGB cable and PAL Gamecube cable.

So... do I just need a different N64 specific RGB cable? Is the console just too old? Is my mod too old skool and I should do a different RGB mod?

I used to have a custom N64 RGB cable and as far as I recall it looked ok on my CRT, but that was 10 years ago and I don't have the cable anymore.. That's why I'm thinking I need to get an N64 RGB cable compatible with mmmonkeyes Method 2 - but where to buy?

-----
Update: Added more photos.
-SNES RGB PAL Cable with 75ohm resistors to ground on R, G, B and Composite Video
-GameCube RGB PAL Cable with 220uF Capacitors in series on R, G & B (and 75ohm resistor to ground and 220uF capacitor in series on Composite Video)

According to http://gamesx.com/wiki/doku.php?id=av:nintendomultiav those cables are perfect for SNES/Cube however for the N64 there is no info.. "N64 RGB Cable components will depend on the mod performed".

Hmm, are either of those SNES or Cube cables I have compatible with mmmonkeys Method 2 mod?

[bobzee]

Have you tried it on another TV and does it look the same?
Some LCD's are really picky about sync errors.

Check that the N64's RF shield still in place, and check the RGB wiring in the console to make sure it's still good.

[fathertime]

Hi bobzee - RF Sheild is in place and RGB mod wiring is still good according to the multimeter.

It may well be the TV.. TV is a 50" Plasma model PS50C680 - I actually don't have any other TV to test on though.

The first post is updated with the RGB cables I have available to me. I guess the question is to ask does anyone know if either of these cable should be giving a good image considering the mod performed? (right now the image is poor with either cable).

[retro]

Have you checked the RGB outputs, sync output, switching output etc. to ensure they're all in range?

[Oldgamingfart]

Yes I think it might be worth trying to disconnect (and separate) the resistors on the RGB and Composite lines (SNES cable), so there is a direct connection from the N64 to the SCART pins.

Also check the grounding for the RGB lines (pins 5, 9, 13, and 17 on the diagram >>here<<). Maybe 'tie up' all the ground points to the SCART outer shield (aka Pin 21), back to the N64 ground.

[fathertime]

Cheers folks for the replies. I'll re-mod and get a new cable.

It seems the whole N64 RGB mod topic is a bit of a mess to be honest... several different mod methods for both the N64 board and the cable itself. Then most of the board mods out there don't even say what is the correct cable to use after the mod.

I wish there was a just one guide for "the Ultimate n64 RGB mod with cable". Maybe I'll try this one first http://www.mmmonkey.co.uk/console/ni...64_rgb_new.htm and use the cube cable.

Will let you know how it goes!

[Bad_Ad84]

Just got my french N64 through the post and ended up with exactly the same problem you have.

The X pattern through all the graphics really kills the picture.

[sanni]

Try using the composite sync instead of composite video as sync signal. Maybe that will help.

[Mamejay]

Try using the composite sync instead of composite video as sync signal. Maybe that will help.

I agree with Sanni. I had the same problems with a PCEngine RGB mod I did when using Composite out for my CSYNC. Onces I changes it over to CSync the x pattern disappeared.

[mdmx]

I had the X pattern problem with my N64 and Super NES RGB cable aswell . I solved it as follows:

open the Multi AV connector at your RGB cable, remove the wire from pin 9 (Composite Video) and solder it to pin 7 (S-Video Y). This mod might not work with a flat screen TV.

[Lum]

I had the X pattern problem with my N64 and Super NES RGB cable aswell . I solved it as follows:

open the Multi AV connector at your RGB cable, remove the wire from pin 9 (Composite Video) and solder it to pin 7 (S-Video Y). This mod might not work with a flat screen TV.

Yup I really need to find someone in the states who mods RGB cables. Perhaps a trick like that might get this here Japanese Saturn to correctly trigger RGB mode, and remove my Genesis 2 cable's jailbars.

[Bad_Ad84]

Update:

I also switched to C-Sync and it resolved all of my N64 quality issues.

My scart lead didnt have a wire connected to Pin 3 (n64 side). So I decided to cut the trace going to pin 9 (composite video) and connect pin 7 (C-Sync) of the S-RGB A chip to the now disconnected pin 9.

This allows me to use my unmodified RGB scart cable with the N64, with C-Sync on pin 20 (scart side).

I obviously wont get composite out of it anymore - But if I wanted composite I wouldnt have gone to all the trouble of getting a RGB moddable console in the first place.

[fathertime]

Guys, thanks for all the advice.

A couple of things -

First of all, I picked up a retro 29" Sony Trinitron CRT. This thing is HUGE and weights a ton so I can't get it into the house just yet. It's out in the shed for now but I hope to test it soon and I'll let you know if it looks good on a CRT.

The second thing purchased is the 'Sync Strike', 'cga2vga Scaler' and 'SLG3000' - I'm sure a lot of you guys know about this set of products but apparently it is supposed to take in a Scart RBG cable, clean up the composite sync to a clean c-sync, output to VGA and then the SLG3000 adds nice scanlines on a 50" plasma! Can't wait for this package to arrive.

Thirdly - also still waiting on the THS7314 for the RGB amp mod but have all the other bits ready to go.

If after all of this, the image still looks poor, then I'll consider your advice on the PCB c-sync to composite mod. From past experience though, when I cut a trace it will be destroyed forever ;)

[Bad_Ad84]

I have a homemade "sync strike" and a cga to vga scaler - as detailed here: http://www.mmmonkey.co.uk/console/other/rgb2vga.htm

It still looked like crap until I switched to C-Sync.

[link83]

Was there a 75ohm resistor to ground on Composite video inside the SCART cable? If not thats likely the reason for the poor sync signal since all PAL N64's need this.

Also its worth knowing that C-Sync is only present on specific N64 motherboard revisions, so its not a solution that can be used on all N64's.

[fathertime]

Was there a 75ohm resistor to ground on Composite video inside the SCART cable? If not thats likely the reason for the poor sync signal since all PAL N64's need this.

Also its worth knowing that C-Sync is only present on specific N64 motherboard revisions, so its not a solution that can be used on all N64's.

Inside the scart cable there is a 75ohm resistor to ground and 220uF capacitor in series on Composite Video. Is that right? (It's a PAL Gamecube RGB cable being used on a USA N64 - you can see it in the first Scart Cable picture in the first post).

[link83]

Inside the scart cable there is a 75ohm resistor to ground and 220uF capacitor in series on Composite Video. Is that right? (It's a PAL Gamecube RGB cable being used on a USA N64 - you can see it in the first Scart Cable picture in the first post).

No NTSC Nintendo console requires external components on Composite video (i.e. inside the cable/plugs)

I just took a look at your first post and can say that if you have used Method 2 from that guide with the 'internal boost' part from the bottom of the page then that will be the cause of your problems. It is strongly not recommended, and I emailed mmmonkey some months ago and he updated the guide. If you look at the top of the guide there are now links to better mods that use an RGB amplifier to give a much better picture. I am afraid there is no way to just 'join a few points' in the N64 and get a good RGB picture, you have to add components.

The quote from GameSX which states "N64 RGB Cable components will depend on the mod performed" was written by me, and it means exactly what it says. Some amp designs will allow you to keep the 220uF capacitors inside the cable since they are needed for the circuit anyway (So no point in removing them) Other amp designs will expect a straight connection to the TV - you have to look at the amplifier schematic (of which there are quite a few) to determine whats best for your particular mod, although most expect a straight connection with no components inside the cable/plugs.

[fathertime]

This package arrived :clap:


Looks like you need to order the VGA cables separately so no testing just yet... :-(

[Bad_Ad84]

There wasn't originally a 75ohm resistor in the cable, I did add one. But, it made no difference either way.

And which RGB moddable N64's dont have C-Sync available? the NTSC ones? I was under the impression all RGB moddable N64's have C-Sync. The french one certainly does as I am using it.

I thought pin 14 on the VDC-NUS was C-Sync?? which is on the NTSC console.

[link83]

Hmm, a 75ohm resistor to ground (Not in series) should have fixed it, glad you got it sorted anyway :nod:

NUS-CPU-04 is an RGB moddable NTSC N64 that has C-Sync output removed, but its also absent from all subsequent NTSC motherboard revisions as well (Although they are not easily RGB moddable either) Also, no PAL N64s (French or European) have C-Sync output available as standard either.

For anyone interested in more info please see my thread about N64 motherboard revisions here:-
http://forums.benheck.com/viewtopic.php?f=5&t=27684

<EDIT>The VDC-NUS chip is only present on the first four NTSC motherboard revisions and the French specific N64 motherboard. Pin 14 is C-Sync, but you should not use it directly as it needs to be buffered - its these buffering components which are removed on the NUS-CPU-04 motherboard revision.