RGB modding on a PAL NES

[6502freak]

Hello folks,

i was wondering if someone managed to mod a PAL NES board to RGB using a 21,47Mhz Oscillator, 2A03 CPU and a 2C03 PPU.

Basically, what I just need to know is: do the PAL 2A07 CPU & 2C07 PPU chips have the same pinout as their 2A03 and 2C02 NTSC counterparts? Since there are no PAL NES schematics available on the net, I am asking if someone knows for sure that the pinouts are identical.

If that's the case, then I am going to mod one of my PAL NES consoles to a NTSC RGB console using the PPU and CPU from my Playchoice 10 arcade board, which is collecting dust here. The biggest advantage is the sharper picture, and being able to play NTSC games in colour on most PAL television sets.

Thanks for your answers!

[Jeroen]

You'd have problems with the internal clock dividers inside the pal nes cpu and ppu. (iirc)

edit: oh wait you want to make it ntsc. I suppose it should work then. To my knowledge the cpu and ppu pinout is the same.

[6502freak]

You'd have problems with the internal clock dividers inside the pal nes cpu and ppu. (iirc)

edit: oh wait you want to make it ntsc. I suppose it should work then. To my knowledge the cpu and ppu pinout is the same.

That's also my assumption, because so far, the pcb traces of my PAL board (NES-CPU-11 (C)1987 Nintendo) match the traces seen on photos of NTSC boards. But I just wanna be 99% sure before I expose my precious 2C03 PPU to potential danger.

Thanks for the help.

[Jeroen]

welll cpu is the same. It works for my pal copynes

[6502freak]

welll cpu is the same. It works for my pal copynes

Wait, you did change the 2A07 CPU to a 2A03 CPU, but kept the 2C07 PAL PPU?

[Jeroen]

you plug copynes in between the nes board and cpu. So the pinouts the same.

[6502freak]

you plug copynes in between the nes board and cpu. So the pinouts the same.

Duh, of course!

Now I need someone to confirm that both PAL and NTSC PPU's have the same pinout. Or am I the first PAL NES user who wants to perform a RGB mod on his console?

[6502freak]

Case solved, both NTSC and PAL PPUs share the same pinout!

Well then, one PAL NES is going to get a nice makeover in the next few days...

Finally, I can develop on a native NTSC console and simultaneaously play shoddy PAL versions like Mega Man 2 and Castlevania at the correct speed and sound pitch!

[mark_k]

If that's the case, then I am going to mod one of my PAL NES consoles to a NTSC RGB console using the PPU and CPU from my Playchoice 10 arcade board, which is collecting dust here. The biggest advantage is the sharper picture, and being able to play NTSC games in colour on most PAL television sets.

You could buy a French NES console. They have RGB output on a special 10-pin multi-out socket.

Before you get all excited, the RGB output isn't RGB quality! The French NES board is the same as other PAL boards. The difference is in the video/modulator section, which contains a PAL-to-RGB video decoder. So picture quality is pretty much the same as a normal PAL NES, except you can't adjust colour intensity on most TVs.

I mention that because if you're fitting an RGB PPU, it might be worth getting a French NES. You could potentially connect the RGB output pins of the PPU to the correct place in the video/modulator box (maybe cut some traces in there too), to have the signals amplified/buffered inside the console. And you could use the RGB/SCART cable that comes with the console to connect to your TV.

Of course the down side to that, or modifying any originally-PAL console that way, is that you'll need to desolder both CPU and PPU in addition to the crystal. Or maybe you can get an NTSC NES main board and replace the modulator with one from a French NES?

[Lord Nightmare]

AFAIK no PAL RGB PPU exists. The french NES has a PAL composite ppu along with a PAL->RGB converter.

LN

[mark_k]

AFAIK no PAL RGB PPU exists. The french NES has a PAL composite ppu along with a PAL->RGB converter.

I know.

What I was suggesting was, inside the power/video box of the French NES there may be circuitry that amplifies/buffers the RGB lines, similar to what you would need to implement yourself. That could be tapped into/used when making a full-on RGB mod (which would involve replacing the CPU, PPU and crystal). And having RGB out on the already-present RGB-out port would be a really neat solution.

I haven't looked inside the French NES video box -- they are really hard to desolder and I don't have a spare to work on anyway -- so that may not in fact be possible. For example, if there's a single composite->RGB decoder chip which provides already-buffered RGB outputs. But it'll definitely be worth looking into.

Another reason the French NES video box could be interesting is if the composite->RGB chip is multi-standard; then by perhaps changing external components it could be possible to make it work for NTSC input. Very useful for people in PAL countries whose TVs show NTSC in black and white.

-- M

[rt9342]

I happened to come across this thread. I don't know if this info. is too late or already answered, but the NTSC CPU & PPU (RP2A03 & RP2C02) have the exact same pinout as the PAL CPU & PPU (RP2A07, RP2C07). In fact, the NTSC & PAL motherboards are IDENTICAL - it's the same board - the only difference is in the parts. These are the parts that are different: CPU, PPU, CIC (lockout chip), RF modulator/power supply, X1 (clock crystal), identification label (just a sticker to identify whether the board is NTSC or PAL). Everything else is the same. I have an NTSC board with the lockout chip disabled and sockets for the CPU, PPU, and crystal; all I have to do to convert it to PAL (if I use the A/V jacks, rather than RF output) is change out the CPU, PPU, and crystal - that's it. By the way, as long as you have the right PPU and crystal, you can interchange the CPUs, but the music will be in a different key, and some games may experience graphical glitches. Also, when using the PAL PPU with the NTSC configuration, slow-down will occur more often and will be worse. Hope that helps.

[MeTrOiD_shift1]

Hi, rt9342.

I am interested in some info you may be able to help me with...

I am trying to make an (auto) switchable 50/60Hz NES.
I have the 2C07 and 2A07 running fine with the 26MHz crystal.
If i change the crystal to the NTSC (21MHz) one, i get the system RUNNING, but no syncable video output (but there IS an image there).

I have swapped the CPU (piggybacked the 2A07 and 2A03 but disabled the 2A07).
I have (at EACH 21MHz and 26MHz, AND 14.318MHz) got either a dead 2A03, or a system in lockup. (screen syncs to blank at 26MHz).

You mention "By the way, as long as you have the right PPU and crystal, you can interchange the CPUs, but the music will be in a different key, and some games may experience graphical glitches."

What are the right PPU and crystal i should be able to use, or is my 2A03 dead?

I have the 2A03, 2A07, 2C07, 21MHz, 26MHz and various other crystals at my disposal. I am currently in search of a 2C02/2C03, as until i read your post, assumed the CPU/PPU need to be paired correctly....

But if i plan to have the correct pitch/tone/speed, do i require the 2C02/2C03 regardless? The clocking on the schematic is a little crazy to me, and i can't work out what takes control of the speed...

I am currently working on this in this thread at NFGGAMES:
http://nfggames.com/forum2/index.php?to ... 2#msg28702

[Live_Steam_Mad]

Hello folks,
i was wondering if someone managed to mod a PAL NES board to RGB using a 21,47Mhz Oscillator, 2A03 CPU and a 2C03 PPU.

Yes. See this page ;- http://nfggames.com/forum2/index.php?topic=1592.40

>Basically, what I just need to know is: do the PAL 2A07 CPU & 2C07 PPU chips have the same pinout as their 2A03 and 2C02 NTSC counterparts? Since there are no PAL NES schematics available on the net, I am asking if someone knows for sure that the pinouts are identical.

Yes. RP2A03E NTSC CPU has same pinout as RP2A07A PAL CPU. Their internal clock dividers are different (NTSC CPU has 12x divider from 21.477(27R)MHz Crystal and runs at 1.78977(27R) MHz and PAL CPU has 16 x divider from a 26.6017125MHz X'Tal and runs at 1.66260703125MHz LOL).

PAL CPU also has different values of components in the audio section than NTSC CPU to take into account lower speed of operation (50Hz instead of 60Hz). However this doesn't explain when I try PAL NES with PAL Super Mario Bros 1 and the music plays too fast. When I try NTSC with NTSC Super Mario Bros 1, speed is same as PlayChoice 10 (perfect).

Yes, pinout of RP2C02E-0 NTSC PPU is the same as RP2C07-0 is the same as RP2C03B (PlayChoice 10) is the same as RC2C03B (Tennis / Duck Hunt) is the same as RC2C05-99 (Famicom Titler) is the same as RC2C05-01,2,3,4 (see above topic, watch out for address lines A0,A1,A2 needing Baku's logic circuit mod).

Some person on that forum I posted the link to has done the RGB mod to his PAL NES by transplanting NTSC X'Tal and NTSC CPU into PAL NES PCB, as rt9342 mentions. Relatively easy to do, and you can get the NTSC CPU with legs intact, ready for putting into the newly soldered in CPU socket on the NES PCB, by taking it from the PlayChoice 10 PCB, which has an RP2A03. Make sure to disable the CIC chip (break off pin 4 of CIC) otherwise no NTSC games will load I suspect! Probably not worth it though since PAL boards I think tend to be late revision ones and will therefore show jail bars much worse than the early (e.g. revision 6) NTSC NES's.

>If that's the case, then I am going to mod one of my PAL NES consoles to a NTSC RGB console using the PPU and CPU from my Playchoice 10 arcade board, which is collecting dust here. The biggest advantage is the sharper picture, and being able to play NTSC games in colour on most PAL television sets.

The big advantage to RGB picture is sharpness PLUS the REMOVAL of zig zag lines on vertical edges that the NTSC encoding generates. If you look at my screen shots in that forum you'll see that NTSC looks OK but has zig zags, whereas PAL looks absolutely terrible.

RGB PPU will change your color palette significantly. The visual result depends on the game. Most look more vibrant and still look nice. Some don't work at all, some look awful. RC2C05-04 (NOT the titler's RC2C05-99 PPU, the one from some VS. games) allegedly has the NES palette, I'm trying to verify that for sure. Bear in mind that the latter PPU requires alteration of memory address lines 10,11,12. See Baku's schematic, he was the first guy to solve this problem (he's a Famicom genius).

Palette in 2C04-ox is different and not usable at the moment.

Cheers,

Alistair G.

[TmEE]

Pinouts are same, but internal dividers etc are not. The PPU is locked to 50 or 60Hz, you cannot make a 50Hz PPU do 60Hz and vice versa.

Boards are same too, differences being the part as mentioned earlier.

Regarding Super Mario, if it is PAL version then it has music speed adjusted so it would not be so slow, and if you play it on a 60Hz machine the music will be way too fast.