PAL N64 s-video problem

I hope this is the correct board for my new thread.

I have a PAL N64 serial #NUP1638xxxx. I would like to connect it with s-video to a video projector. So I bought a s-video cable for SNES/N64/GameCube. This works fine with my US N64, but unfortunately the PAL N64 produces a much too bright picture.

I did some research and heared that people fixed this issue with two 75 ohm resistors on the luminance and ground lines.

So I bought 2 75 ohm resistors (5watts) and soldered it as described. Unfortunately without success. The image is still too bright.

I also heared that s-video is not possible with later N64 models. So I borrowed a N64 from a friend serial #NUP1269xxxxx. Unfortunately I have the same bright image.

I don't know what I can do now:shrug: I'm pretty sure that I soldered everything correctly:




I would be happy about any help

 

funny thing. When I connect my PAL N64 via RCA to the WEGA TV (CRT) we have, the colours are too bright as well! (un-playable)

The NTSC is fine though.

Comes to show how NTSC stuff is better i guess;p

 

Don't put a resistor on the ground line, try it on just the luminance. If that doesn't help, if you can, buy a small 1K potentiometer, connect it as a variable resistor then replace the 75ohm resistor with it. BTW, you can use normal 1/4W resistors for video work (~1Vpp)

 

I soldered two 1k potentiometer to luminance and to chrominance because only on luminance wasn't very helpful. The picture is better but still not as good as on the US machine.

 

It's the luminance amplitude which determines the brightness, I would try a voltage divider with two pots.

 

Just chip a NTSC N64 to play your PAL games - will that work......??

 

from my fuzzy memory you'd need the extra chip off PAL N64 to make NTSC N64 dual zone...???

 

I don't know if it's possible to PAL mod a NTSC N64. The only way would be to replace the security chip on the mainboard.

Does anyone ever tried something like that?

 

You'd need to replace the video DAC (on earlier boards it's VDC-NUS, later MAV) and possibly the peripheral chip which talks to the CIC chip on the cartridge.
Probably the DAC would be all you'd need. Worth a try, anyway.

I have a dead NTSC n64 mobo here which has a working video DAC (generates a dark green screen). If you are interested in it, let me know.

 

Hmm yeah, always wanted to try that. Maybe next time I'm in NYC i'll see if I can pick up a cheap NTSC unit.. I know I have a spare PAL one that I can cannibalise!

 

I decided to post some pictures about the problem. As I wrote before, I have a potentiometer on the luminance line. I can make the image darker, unfortunately not all colors are going darker. Have a look at Goldeneye: The image is set very dark, but the red/yellow colors light like a fire.



this happens also with blue and green, differs from game to game.

 

A guide I often use is viletim!'s post in thread below. It explains source impedance, transmission line impedance and load impedance.
http://nfg.2y.net/forum/index.php?showtopic=1733

Code:

Generic video circuit 
.   A   (220µ)  (75)           C
.  +@----Cc------Rz---@---TL---@+---Cin---->
.  |                  B         |
.  Zo (0)                  (75) Rl
.  |                            |
. ---                          --- 

A - video IC output
B - console video connector output
C - TV input

In this case:
Chroma = (A) DENC-NUS pin 19, (B) MultiAV pin 8, (C) TV s-video pin 4
Luma = (A) DENC-NUS pin 18, (B) MultiAV pin 7, (C) s-video pin 3

So for the best picture there should be 75 ohm and at least 220µF beetween A and C, IF the TV is like descripted inside. But I guess TVs might be different, and maybe that is way people at other forums get different results with different TVs.

Here is a scan of the (B) MultiAV connector on my PAL N64:


As you can see chroma have C11 as Cc, and luma have C12 as Cc. I would check these capasitors out. As you know the capasitor's impedance is frequency dependent, and that might be part of the explanation why there are different results at 50Hz and 60Hz.

I would try to:
a) replace C11 and C12 with 220µ (or 470µ) capasitors
b) make sure that signal from the video IC to TV is going through 75 ohm

CF

 

s-video for pal n64

Hi. This might be old news :katamari:, but here is how I made s-video cable for PAL N64. And it works great, on PAL N64 + USA and PAL SNES.

Pic: http://www.elisanet.fi/sjk/temp/svideo_for_pal_n64.jpg

Note: I wrote that it works on USA N64, but it does not, sorry about that. On USA N64 don't put the resistors at all. Funny thing is that it works on USA SNES.

 

I saved that some year ago, it's the pal/ntsc region mod. I took that from an old d4s website IIRC

 

Putting a resistor to ground on the source end doesn't make sense since with the 75 ohm load resistor in the TV (which should be there), they will be in parallel and in effect turn the 75 ohm load into a 37.5 ohm which will raise the level from 1Vpp to 2Vpp (bad!)

 

The official Nintendo AV-cables have the same 75 ohm resistor connecting ground and the video. Why? I don't have a clue. Open one and check, if you don't believe. It is the same way that makes the s-video work on PAL N64. Normal (OLD) AV-cables that were used with SNES, do not have the resistors, that is why they do not work on PAL N64, and the colors looks like overburned!

 

I understand now, the N64 must not output 1Vpp (0.7Vpp without sync) into 75 ohm which is the industry standard, it must purposefully output 1Vpp into 37.5 ohm. Why the resistor is in the cable and not inside the console I don't know...

 

NTSC cable don't have any resistor, I think that pal stuff are just weird by definition..

 

Yeah, pretty weird indeed. Possibly one of Nintendo's sick ideas not to be able using an import AV-cable :icon_bigg, sure. Or could Nintendo be so stupid to screw up the whole production of N64 motherboards and just patching the cable. I would like to know the real reason for this whole video output issue on N64. Like, why there is no RGB.

I have this "so called RGB" cable for N64 (Blaze's ULTRA64 Scart Cable). I bought it in 1997. It was used for NTSC version to show the picture in an old 50hz tubes. Now there is no reason to use it, because those old junk-tvs are gone forever :clap:!