Audio from N64 but no Video after basic RGB mod

[0chaos0]

Hey,

Just installed Voultar's basic RGB mod for the N64, and I'm getting audio but no video.
Looking for any advice on what to check.

Could be compatibility issue, or maybe poor installation, wrong cable, etc.

Any input or direction to check first would be rad.

 

[koffieleut]

Have you tried another tv?

 

[0chaos0]

Tested setup with other N64, everything looks fine.
Tested with different jump/expansion cards.
Tested RGB cable with SNES, works fine.

 

[Coto]

I did RGB a N64 3 years ago but it seems you used a custom premade converter, (while I used a GBS-820) your best bet would be asking out at the seller's place.

Also because the older RGB mod could be performed on the R-G-B lines present through the vdc-nus older n64 motherboards had. (as opposed to mav-nus). If anything check for solder joints or cold joints (the n64 motherboard will require a good soldering iron).

also on the seller's site it says:

"My RGB kit is only compatible with N64 consoles that has a serial number beginning with NS1. If your N64 console begins with a serial number other than NS1, it is NOT compatible."

 

[0chaos0]

Yeah I'm going to reach out to Voultar next I think.

Here's some quick photos I took of it and the board.
imgur.c om/a/tc0ewnD

I did attempt to resolder the RGB lines after it didn't initially work, to no avail.

As for the compatibility, AFAIK NS1 just usually means 01-04 revisions of the board, mine is a Canadian unit so it's a NS6, but has the -04 rev so it _should_ work. That being said it could be a odd variance in the model.

 

[Coto]

Yeah your N64 is RGB moddable (I have two of them that are either CPU 02 or 03). Also the solder work looks clean. Perhaps the blue cable I couldn't see it very well so i'd rant about that one.

Other than that, since it seems to be an all in one chip, those require heavy timings (from the clock source) and the C-SYNC generator seems to be stripped from the embedded C-SYNC circuitry. iirc some N64s DID have the C-SYNC cut, thus, no video "sync" even if the signal is correct. In your case your motherboard has those ripped off:

http://nintendo64.wikia.com/wiki/NUS-CPU-04

And you need to generate that signal. Or either use a LM1881c-sync generator from composite video.

What I did (IIRC), the gbs-8220 generated own V / H Sync signals (15khz according to VGA standard). And I used the C-SYNC directly from my motherboard, a NUS CPU - 03 (into the S), signal:

(output lines from VGA port out)
C. RGBHV
30.5V - 32.5K
AUTO SCAN

and the setup (RGBS Setup):

(input lines )
N64 C-SYNC->H. Sync to Gray Wire/P11 (S)
•
N64 Red Line -> Red Video to Red Wire/P11 (R)
•
N64 Green Line -> Green Video to Green Wire/P11 (G)
•
N64 Blue Line-> Blue Video to Blue Wire/P11 (B)
•
(disconnected) V. Sync to Yellow Wire/P11 (VS)
•
N64 Ground Line -> Ground Ref to Black Wire/P11 (GND)



So your device must generate C-SYNC since that motherboard is missing the C-SYNC logic. And if no c-sync signal is present you won't have video out or wrong video

 

[0chaos0]

So the chip page voultar. com/index.php?route=product/product&product_id=50

Which if I understand correctly restores the CSYNC, but has some options. Should I perhaps try the TTL solder strap?

 

[Coto]

You can´t really generate C-SYNC on your own since the signal must be sincronized with the VDC chip. But it seems you were lucky there.
Since I never had ths issue myself, I tested C-SYNC through a capacitor, then through the VDC chip.

Also some guy managed to restore the C-SYNC signal on a NUS - CPU - 04 (and that´s why you are lucky):

"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"

So basically wire Pin14 from VDC chip into C-SYNC input from your device (the S leg on the embedded IC). IIRC I also did that because the C-SYNC signal was too weak for the converter I was using.

also I had to lift each RGB leg from the VDC chip or the signal would be too weak to display any image. (and that disabled composite video out). This is a NTSC N64 whose region should be the same as the one you have. PAL n64 instead have 12V+ instead of composite sync... but that is not an issue here.. ugh