Is it possible to reproduce the NES CPU and PPU?

I have seen people trying to do the NES hdmi mod, where they have ruined the chips when trying to remove them.
People often seem to buy a whole new NES-motherboard to try it a second time.

Why is it that we can't reproduce these chips, with some reflashed newly produced one, like on some of the Commodores?

 

Well would be good if someone could make new chips with the silicone wafer like how they where originally manufactured i found desoldering nes ppu and cpu if you have the right desoldering tools i used Desoldering Station ZD-915 works perfect even for sega mega drive cpus

 

Iirc the CPU is an off the shelf CPU that is still manufactured today. Maybe FPGAs could replace them if needed.

 

i have watched gametechus on youtube a lot back when we was still doing nes stuff and have always wondered myself about this, i believe there is a company making ppu's but i think they are pal only even if they say ntsc but i cant really remember

 

No, both the CPU and PPU chips are custom chips. "We" can't reproduce these chips because they were made in an industrial facility and not someone's garage. They are not magic, they are integrated circuits. With enough money you could certainly have them produced again. But considering the cost it's not economical to do this. You could possibly make a standalone clone of each chip using a FPGA and other components. This obviously is done in the Analogue NT Mini and the RetroUSB AVS clone consoles.

The Commodore computer may use a standard 6502 CPU chip. This makes replacement not a big deal. I'm not sure what you mean by "reflashed". Integrated Circuits are not "flashed". Certain programmable devices might be. But that's not the same as creating new ICs are are drop-in replacements for the original chips.

 

Ah ok. I could've sworn I read somewhere that the CPU was off the shelf. I guess wherever I read it was wrong.

 

The CPU is a customized 6502 which is a "off the shelf" CPU. The SNES is the same situation where the CPU is a 65816 but the chip that contains that also is custom and contains other hardware for custom features. Ricoh produced both for Nintendo.

 

That makes much more sense. Thanks for the clarification!

 

It should be technically possible. Mark Smith managed to clone the ULA on ZX Spectrum 128. Google "ULA SLAM".

 

Expense, basically. It'd cost too much money. For the sake of preserving old hardware, I hope someone does come up with a drop-in replacement someday, but without a wealthy benefactor or improbably successful crowd funding campaign it's not likely to happen any time soon.

 

Or maybe advances in manufacturing might make it more economical.

 

i remember hearing a while back about a repro ppu but it was pal only

 

Exist 2 project dont finish...universal PPU and Universus. My Xmas gift when I was young my first console NES pal modded with CPU/PPU US and NES Hi def (HDMI from Kevtris ingeneer of Analog). Missing 3 thing: double sprite option, free region (US game on PAL PPU/CPU slow or EU game on US PPU/CPU too fast...) and add missing arcade palette.
So source code about and schem about Universal PPU is avallable, if some one can finish it and be compatible with NES HI def...

 

"drop-in" "repro"s have been around for a long time. Supposedly they're not as good as the real thing but I've never noticed anything particularly bad about them. Bad famiclone sound is a meme largely perpetuated by people who have never heard what an actual original famicom sounds like with it's filtered RF output. Modern man has been able to reverse engineer ancient Chinese technologies like copiers to create flash carts. It's only a matter of time before he advances to the point of being able to reproduce more complicated things like a bootleg 8 bit CPU.

 

The reason people thought that the sound on most famiclones sounded off was that it did. The commonest chipset used in the early clones was made by UMC and apparently designed by TXC/Micro Genius - it was a pretty good copy, but it had an error in the sound subsystem that effectively swapped over the 25% and 50% duty cycle settings - the result of this was fairly subtle but it did mean it sounded wrong to people that were used to the original Nintendo chips. When UMC made their single-chip NES device, they basically merged the CPU and PUU designs into a single layout, so the same error occurs there.

 

Subtle is being generous. In certain games the effect of the swapped duty cycles is blatantly obvious. In some games I would agree that it's more subtle. I think SMB's Coin sound is really wrong and also the jumping sound. You could simulate it in an emulator.