NES Schematics

This is an archive of a topic from NESdev BBS, taken in mid-October 2019 before a server upgrade.
View original topic
NES Schematics
by on (#215001)
I'm working on an art piece involving the NES-001 schematics, and I'm having trouble finding a correct version of it. Each one seems to have different deficiencies.

So far I have found:
Console5 , which has some obvious incorrect connections in regards to pin 65/37 on the cartridge connector (clock line connected to an address line) It's also hard to read many of the labels, making it even harder to use.
Famicom - Which is useful, but obviously the famicom and NES cartridge connectors are different, and the lack of the extension port does not help.
Hackaday.io - Missing most of the support circuits, but otherwise appears correct for IC to IC connections.

Are there any versions I'm missing, or other definitive versions that people reference?


For those curious, I'm working on making something similar for the NES - to this one I did for the Commodore 64. I'm making a new schematic from scratch for this piece that avoids named nets, hence realizing the issues with the other schematics.
Re: NES Schematics
by on (#215003)
Definitive? No, but I have been occasionally working on fixing the Electronix Corp reverse-engineered schematic that's on console5, here
Re: NES Schematics
by on (#215005)
Thanks - that one is definitely better :)

I have a feeling I need to buy an NES-001, and check the nets myself... All I have right now is a top-loader.
Re: NES Schematics
by on (#215008)
I haven't noticed anything else obviously wrong with the existing schematic.

Uh, ok, there's a few pin numbers that are wrong but you said you were going to remove them anyway.
Re: NES Schematics
by on (#215010)
Did I just help you find more issues with it? Yay :)

I'm keeping the pin numbers, I'm just trying to avoid named nets in the diagram I'm doing. I like seeing real traces going from chip to chip.
Re: NES Schematics
by on (#215011)
Not so much "find more issues" but "provide a kick in the pants to upload the corrections I made two months ago"
Re: NES Schematics
by on (#224818)
I came across this by random, and it seems to contain most of the NES schematic on pages 33-34

http://www.videogameconsolelibrary.com/ ... 9sv111.pdf

I'd say this is the closest thing to an official NES schematic we are likely to find :)
Re: NES Schematics
by on (#224820)
From centering and size adjustments on page 9:

>Select a local channel.

First thought: "Why would you need to do that?"
Second thought: "There wasn't 240p Test Suite back then to turn any random console found in the field into a cheap signal generator."
Third thought: "Now that only low power channels are compatible with analog receivers, good luck finding a local channel."
Re: NES Schematics
by on (#224826)
On page 25, they give the pinout for the PPU, a 74'368, and what's supposed to be the CPU ... but is actually another copy of the PPU :(

I'm also amused (from the PCB reference on page 18) that they basically just used the NES-CPU mainboard verbatim. The only obvious changes of layout are the omission of the RF modulator and changing the power supply input. It even includes a space for the expansion connector.

Page 33 does appear to provide a name for CPU pin 30 ... which appears to be "REDY" ???
Re: NES Schematics
by on (#224827)
The Sharp NES TV's NES mainboard is shown off in this video : https://youtu.be/1_9GsVBJ5bw?t=313

There are subtle differences between that mainboard and the regular NES mainboard, such as the different connectors and the complete removal of the RF box. Note the different silkscreening and designation style as well.
Re: NES Schematics
by on (#224831)
That's a pretty neat find. I'd seen that service manual listed somewhere before, but I never expected it to have the NES schematic in it.

lidnariq wrote:
Page 33 does appear to provide a name for CPU pin 30 ... which appears to be "REDY" ???


Huh. Meanwhile, the one schematic I know of that actually controls pin 30 (PC10) just leaves it unnamed.
Re: NES Schematics
by on (#224833)
I mean, we know it's definitely not 6502 RDY ...

I could have sworn the PC10 schematic called it ... SPECIAL ? (looks) OH, I see, on the package it's unlabeled, but it goes to the /SPECIAL net.
Re: NES Schematics
by on (#224840)
If you're interested in some famiclones schematics, Esrael Neto has revised and redraw one here and other here.