NESRGB with SNES SCART cable? (re: sync not working)

[sofakng]

I'm having a problem with my NES and my PVM monitor. I'm pretty sure this worked a few months ago but I put it away in storage and haven't used it.

The NES is a front-loader with an NESRGB 2.0 and an NES I/O board (older revision) and a multi-out port.

The CS# pin from the NESRGB is wired to the NES I/O multi-out. (no resistors I think!)
NESRGB J8 is closed (set for 75 Ohm C-SYNC).

The SCART cable I'm using is wired for C-SYNC and attenuated with a 470 Ohm resistor.

The current SCART cable and settings causes the OSSC to not detect any signal and my PVM has a picture but it's completely out of sync.

Do I need to change NESRGB J8 from CLOSED (C-SYNC) to OPEN (TTL) ?

[Guspaz]

If the NESRGB is set for 75ohm, you don't nee the resistor in the cable. The resistor in the cable is only needed if the device is sending TTL.

[sofakng]

Got it, thanks!

I've found a "TTL" cable (presumably without a resistor) that works. It sounds like the other consoles (SNES, Genesis, GCVideo, etc) all output TTL C-SYNC which requires the resistor in the cable?

By the way, is there a lookup table with each console the correct RGB cables?

For example, the SNES also requires 220 uF capacitors on the R/G/B lines, right? What about the N64, GCVideo, etc?

[Jon Nielsen]

Got it, thanks!

I've found a "TTL" cable (presumably without a resistor) that works. It sounds like the other consoles (SNES, Genesis, GCVideo, etc) all output TTL C-SYNC which requires the resistor in the cable?

By the way, is there a lookup table with each console the correct RGB cables?

For example, the SNES also requires 220 uF capacitors on the R/G/B lines, right? What about the N64, GCVideo, etc?

Here's a good overview of how scart cables for various consoles are configured:

http://members.optusnet.com.au/eviltim/ ... escart.htm

If you read the descriptions you may notice that the cables differ for various reasons - and that the SNES and GC cables illustrated use composite video for sync, not csync. Use of csync is mostly for supporting specific receiving equipment.

For N64 and NES and other systems that have been modded to support RGB it depends on the mod configuration, and some just choose to target a cable type that's common.

[viletim]

I'm having a problem with my NES and my PVM monitor. I'm pretty sure this worked a few months ago but I put it away in storage and haven't used it.

The NES is a front-loader with an NESRGB 2.0 and an NES I/O board (older revision) and a multi-out port.

The CS# pin from the NESRGB is wired to the NES I/O multi-out. (no resistors I think!)
NESRGB J8 is closed (set for 75 Ohm C-SYNC).

The SCART cable I'm using is wired for C-SYNC and attenuated with a 470 Ohm resistor.

The current SCART cable and settings causes the OSSC to not detect any signal and my PVM has a picture but it's completely out of sync.

Do I need to change NESRGB J8 from CLOSED (C-SYNC) to OPEN (TTL) ?

The problem is you closed J8. It should be open.

J8 will be removed in the next hardware revision because so many people do this! It's fine to connect CS# to a 75 ohm video input with J8 open. There is already a series resister connected on the NESRGB board, but another one in the cable doesn't hurt anything (I do wonder why the cables without a resistor even exist).

[sofakng]

Got it. Thanks!

The NES pinout documentation (https://etim.net.au/nesrgb/NESRGB-Pinout.pdf) says the following:

1. Jumper J8 appears only on board V1.4 (NESRGB14) and later.
It is for selecting composite sync output type.
Open for TTL, short for 75 ohm (recommended).

I'm not sure if that's why I set mine like I did, but now that I understand more about sync (TTL/75-Ohm) I can see what I did wrong.

Thanks again for the help!