nes-101 toploader video mod?

i looked around online and it seems that the best way to improve the video is to use a ppu from a playchoice 10 or vs board, and even then the colors are off.

is there any other work around that doesnt involve taking a ppu off an existing board?

the toploader i would use is pretty trashed and i dont care if it ends up looking like ass. i think i saw one with one of those multi-port av connectors. does anyone know exactly how many revisions there were and what exactly are the differences?

and heres a dumb question, is it possible to play famicom or nes games on the playchoice or vs machines...nevermind as i was writing this i found

http://playchoice.riemen.net/eproms.html

has anyone else tried this?

thanks

 

The official multi-port av USA version is very rare. A revision Nintendo made few units of.

While all famicom ones have the multi-port standard, yet lack RF.

That playchoice 10 mod is expensive. Because those needed chips are disappearing as they get used for mod projects. IIRC they've gone up in price since I last asked about it.

 

Just mod it for composite video with cleaner output or buy a Toaster NES.

 

I've forgotten what top loader revisions can be modded for Famicom expansion audio. That'd basically render another in-game benefit of toaster obsolete. I recall something about a break through discovery of the sort being found. Unless it was a hoax...

 

Total misinformation; people exploit Playchoice PPUs for RGB output, not for clearer composite video (which it does not provide). If you must mod the console, you can get PERFECT composite video with a PNP transistor, two resistors and a capacitor. Or you can rework the video output of the console itself. Any NES can be modded for expansion audio, it only takes a single resistor, but you must also add a jumper wire in your 60->72 pin converter.

 

Calpis

id love details on these various hacks

• PERFECT composite video with a PNP transistor, two resistors and a capacitor.
• You can rework the video output of the console itself.
• Any NES can be modded for expansion audio, it only takes a single resistor, but you must also add a jumper wire in your 60->72 pin converter.

 

The PPU outputs a perfect 0.7V so AV mods need only a common-emitter amplifier (a basic topology with a gain of 1 ie no voltage amplification). With a single transistor common-emitter you get full feedback = perfect linearity. This can be accomplished with the following circuit which has been simplified from the A/V FC:



It would be better to use resistor values of 100 and 330 ohms as not only are they more common but together they very closely match the 75 ohm characteristic impedance for an even cleaner signal. The transistor is any general purpose small signal PNP. I would use a 2N3906 or the Japanese transistor already in the console (this is what I mean by reworking).

As for the audio mod, on the converter you must jumper the Famicom audio input pin to one of the expansion pins on the NES connector. I forget which is preferred, but one is Nintendo ordained because I recall that NES MMC5 games put their audio on the pin. The same expansion pin is tapped inside the console and mixed with the PSG audio with a resistor. The value is up to you.

 

I've heard both 100k and 47k I think for the audio resistor.

 

It depends where in the audio path you mix it in, those values are really high though. Probably the best way to determine a value is to look at a Famicom MMC5 game and a NES MMC5 game. The FC game will include mixing circuitry on cart so you can grab the ratio, scale it to the mixing point, and subtract any output resistance in the NES game's circuit.

 

thank you very much for the information.

 

There's a thread about it on NESDev and I also brought it up on Famicom World (I'm 2A03 over there). I've tried the expansion audio mod on my top loader and while it's not perfect, it works fine for the most part. The original NESDev thread is here: http://tinyurl.com/5va2tqx

This is the method I use when modding top loaders. Originally I used a 2N3906, but now what I do is desolder the 2SA397 already in the system and use it in place of the 2N3906. I found that using the 2SA397 gives slightly better video quality and keeps the vertical line issue to a minimum. Just make sure to isolate pin 21 of the PPU (the pin that provides composite video) and you're golden!