6502freak wrote:
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.