nesdev.org

A little question:
If we ignore region-specific NES versions and the top loader, are there different versions of the NES or are all versions the same?
With games, there are sometimes two revisions: PRG0 and PRG1. What about the console itself? If I bought a standard American NES console in 1985, is it identical to a standard American NES console that was sold in 1990? Is the NES from the first American release completely identical to the one from the Challenge Set (the box that contained "Super Mario Bros. 3")? Or are there differences?

Don't know, but I bet you'd find some minor differences. Maybe they changed the layout slightly, or used different manufactures for the same components.

O.k., layout is not that important (except for the gamepads). I would rather be interested in the technical differnces and if they could have any practical influence.

I think there are different revisions of the CPU chip and maybe PPU chip. Also I believe they revised the hardware to try to prevent various lockout defeating methods. Something to stop hte CIC "stun" methods of running unlicensed carts.

There are three known released versions of the CPU: 2A03 F,G ,and H. F is known to not have the "tonal" noise mode ($400e.7), but is believed almost entirely exclusively used in arcade machines. There almost certainly were revisions A-E, but I don't think we've seen them. I don't know how H differs from G; but it's conceivable it fixes DMA-triggered double reads.

There are five major variants of the NES, and they're visually different: the standard Famicom, the AV Famicom, 'toaster' NES, the NES2, and the AV NES. They have minor variations (Famicom read $4016 bits 3-4 are open bus; 'toaster' NES has the lockout chip).

Beyond that, there are multiple revisions of the mainboard for each. I don't know about anything but the 'toaster' NES, but it has 10 different PCB revisions. AFAIK, those differences are very minor, and mostly pertain to various lockout defeat mechanisms.

Apart from the lockout stuff, have there ever been known things that actually influence the game once it is started?

Here some fictitious examples:

"If you change your weapon while being hit in Mega Man 6, Mega Man will have a wrong color. However, this only happens if you use an NES that was manufactured in 1985. The phenomenon does not occur with an NES from a later date."

"In the game Little Samson you will experience a slowdown at the third boss when you play with the NES from the Challenge Set. On all the other NESes, no slowdown occures there."

"The NES versions produced post-1989 have a little music stutter if too much is going on in Gradius which is not the case with earlier models."

Again, I'm not talking about differences between the actual different NES versions that were even marketed as different versions. I know that a Famicom is not identical to an NES. And a front loader NES is slightly different than a top loader NES. And a European NES is not the same as an American NES.
I'm talking about differences between machines that are generally supposed to be the same: Has there ever been a case where a standard American front loader NES behaves differently than another standard American front loader NES because they were manufactured at different times and thus use slightly different hardware? (Not counting the lockout chip mechanism and the mere tolerance of accepting or declining unlicensed games.)

On PCs, it can make a difference for example what graphic card I use. Has something similar been observed with the NES too? Like that the machines that were produced between April and September 1987 have a certain chip by Sharp while other versions have the chip by Fujitsu. And the models with the Sharp chip have some tearing problems with parallax scrolling, even though the NES was not advertised as a new version and is still supposed to be the standard NES.
Has something like that or something similar ever been observed? Or does every front loader US NES behave exactly the same?

JimDaBim wrote:Apart from the lockout stuff, have there ever been known things that actually influence the game once it is started?

Here some fictitious examples:

"If you change your weapon while being hit in Mega Man 6, Mega Man will have a wrong color. However, this only happens if you use an NES that was manufactured in 1985. The phenomenon does not occur with an NES from a later date."

"In the game Little Samson you will experience a slowdown at the third boss when you play with the NES from the Challenge Set. On all the other NESes, no slowdown occures there."

"The NES versions produced post-1989 have a little music stutter if too much is going on in Gradius which is not the case with earlier models."

Again, I'm not talking about differences between the actual different NES versions that were even marketed as different versions. I know that a Famicom is not identical to an NES. And a front loader NES is slightly different than a top loader NES. And a European NES is not the same as an American NES.
I'm talking about differences between machines that are generally supposed to be the same: Has there ever been a case where a standard American front loader NES behaves differently than another standard American front loader NES because they were manufactured at different times and thus use slightly different hardware? (Not counting the lockout chip mechanism and the mere tolerance of accepting or declining unlicensed games.)

On PCs, it can make a difference for example what graphic card I use. Has something similar been observed with the NES too? Like that the machines that were produced between April and September 1987 have a certain chip by Sharp while other versions have the chip by Fujitsu. And the models with the Sharp chip have some tearing problems with parallax scrolling, even though the NES was not advertised as a new version and is still supposed to be the standard NES.
Has something like that or something similar ever been observed? Or does every front loader US NES behave exactly the same?

I believe no such difference has been documented. The only one may be the earliest no-periodic noise 2A03 (which I think never reached the NES itself) and apparently some early CPU / PPU bugs in the first run of Famicoms (the square button ones).

Alright, then everything is fine.

Didn't they have to recall the Famicom when it was already out because of such a bug?

Yes the Famicom was recalled and re-released later. I'm not sure what the apparent problems might have been. There are some original Famicoms in the hands of collectors.

"If you change your weapon while being hit in Mega Man 6, Mega Man will have a wrong color. However, this only happens if you use an NES that was manufactured in 1985. The phenomenon does not occur with an NES from a later date."

"In the game Little Samson you will experience a slowdown at the third boss when you play with the NES from the Challenge Set. On all the other NESes, no slowdown occures there."

"The NES versions produced post-1989 have a little music stutter if too much is going on in Gradius which is not the case with earlier models."

My bet is that those are fake, or at least involuntary made up by wrong assumptions. I can't see how a different PCB layout or different lockout defeat, or even a different CPU revision, could have those effects.

I think the CPU revision can affect controller reading, and OAM reading though.

A CPU-controlled CIC stunner, such as that seen in Color Dreams games, might need different numbers of resets on different NES revisions, and that might change certain things that depend on CPU/PPU alignment.

There is also an RP2A03 that has no revision letter, I have one on a VS Unisystem PCB. I don't know what's different about it. Some have reported though that an H-revision CPU doesn't work with a few VS games (TKO Boxing was one that comes to mind, if anyone was curious).

I know the first post said no region differences, but one of those that's interesting is that the controllers from the NTSC NES don't work on a PAL NES. IIRC, was something to do with a resistor change on the controller board.

JimDaBim wrote:Alright, then everything is fine.

Didn't they have to recall the Famicom when it was already out because of such a bug?

Yeah there are a lot of differet Famicom board revisions and the earlier square button ones have a problem where they freeze when playing sometimes, but nobody really seem to know the details. Revision HVC-CPU-05 is the last of the square button versions and the only one of them that doesn't have the freezing problem I think. There are round button 05 units as well but some of them might just have had their controllers changed, because the square buttons often broke. The HVC-CPU-XX run has at least 8 revisions.
Then there is the later HVC-GPM-XX run with at least 2 revisons and HVC-GPM-02 being the most common one.

GPM-02 is reported to have a fuse which earlier models don't have and the sound may be a bit different between revisions. It's hardly noticable between the red and white Famicoms though. This video (under ロットロット) http://retrogame-db.com/%E3%83%95%E3%82 ... %E3%83%88/ shows a comparison between many revisions including New Famicom and the Twin Famicom variations.
Other than that I don't know if there's any notacible differences between board revisions when playing games.

Proof of a CPU-08 revision (rare):
http://offgao.blog112.fc2.com/blog-entry-22.html

Proof of a CPU-01 revision (first version I guess, probably extremly rare):
http://offgao.blog112.fc2.com/blog-entry-24.html
The 01 verison seems to play some games without trouble but both Rambo and Fantasy Zone has graphic glitches with this particular unit.

Bregalad wrote:My bet is that those are fake, or at least involuntary made up by wrong assumptions.

Erm, yes they are:

JimDaBim wrote:Here some fictitious examples:

I consciously made up some hypothetical situations to demonstrate what I mean with "different behavior" to ask if something in this category was ever observed. You know, like different graphic cards on PCs can affect the smoothness of scrolling in a game.

Bregalad wrote:I think the CPU revision can affect controller reading, and OAM reading though.

How would this express itself? What could be different?

JimDaBim wrote:

Bregalad wrote:I think the CPU revision can affect controller reading, and OAM reading though.

How would this express itself? What could be different?

I think most games that would be subject to this bug were aware of it so they required the same value for more than one read. Because of this the end user wouldn't notice whether the bug existed or not.

To answer your question: No. There aren't any noticable differences in the different versions of the NES to the end user aside from the CIC circuitry. Meaning that some early pirated games might only work in old NES's. But if the game runs you'll never see any differences. Sure Nintendo could have fixed/improved some minor things but you'll never notice them even if they exist unless you're a dev'r specifically looking for these extremely obscure differences to the end user...

There are no differences on the level of what you're asking 'scrolling is different for different graphics cards' I'd bet large sums you won't find anything like that. If there were, we would have noticed it by now...

As an aside why are you curious? Is there something specific you're wondering about?