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PostPosted: Thu May 24, 2018 12:57 am 
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I was thinking of modding my NES to be able to play Famicom games on it and enjoy the expansion audio as well. I need to ask a few questions related to them to know if it is even worth it on PAL NES.
-Do famicom games run correctly on PAL NES?
-Is expansion audio present and processed on NES carts even if they aren't mixed in with the internal audio?
-Is it possible to get NTSC games to run at correct speed on PAL NES?
-Is it true that the expansion audio can be enabled by soldering a resistor between the audio in and audio out pins on the expansion port?
-Someone said that you need to use a potentiometer instead of a resistor to be able adjust expansion audio to correct levels between games. Is this actually true?
-What size of resistor/potentiometer should be used?
-Are there connectors available that would fit the expansion port? I'd like to solder the resistor/potentiometer to it rather than the expansion port directly.

Any other things I should know before doing these mods?


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PostPosted: Thu May 24, 2018 1:09 am 
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SusiKette wrote:
-Do famicom games run correctly on PAL NES?
Sometimes. Really depends.
Quote:
-Is expansion audio present and processed on NES carts even if they aren't mixed in with the internal audio?
Usually no. Of all the mapper ICs that generate sound, only the MMC5 was also used in places that used the 72-pin connector. And even among those, the physical ROMs on games released in 72-pin land don't program values into the MMC5's sound registers.
Quote:
-Is it possible to get NTSC games to run at correct speed on PAL NES?
No.
Quote:
-Is it true that the expansion audio can be enabled by soldering a resistor between the audio in and audio out pins on the expansion port?
Approximately. (There's other variables, like "what carts do you want sound from")
Quote:
-Someone said that you need to use a potentiometer instead of a resistor to be able adjust expansion audio to correct levels between games. Is this actually true?
-What size of resistor/potentiometer should be used?
Using a potentiometer lets you tune the relative volumes of the internal audio vs expansion audio. I've seen people recommend values from 20k to 100k, but most people seem to use 47k?
Quote:
-Are there connectors available that would fit the expansion port? I'd like to solder the resistor/potentiometer to it rather than the expansion port directly.
Not really. Years ago Chykn made a small run of bespoke things, called the ENIO. InfiniteNesLives claims they're still being made? INL has also been working on simple card that can be inserted instead: see here.


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PostPosted: Thu May 24, 2018 1:56 am 
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lidnariq wrote:
SusiKette wrote:
-Do famicom games run correctly on PAL NES?
Sometimes. Really depends.


The speed they run at is what I'm mostly concerned of. If they run at incorrect speed it might be better to just get NTSC NES and mod it instead. I'm assuming the PAL NES power supply works for NTSC NES as well. I doubt they have different output specifcations. Can a PAL TV (if TVs even have regions) handle NTSC signal?


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PostPosted: Thu May 24, 2018 2:16 am 
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As for the 47k resistor, that’s just a very common value on a resistor in general. Different games/audio chips will be louder/quieter, so there’s not really an optimal standard. The potentiometer will let you adjust to taste, though.

I’d advice to wait for INL:s expansion port dongle (pro: least amount of modification), but there’s no ETA on that afaik.

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PostPosted: Thu May 24, 2018 2:36 am 
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SusiKette wrote:
The speed they run at is what I'm mostly concerned of.

The speed will always be wrong. Every NES/Famicom game I'm aware of (except for a select few homebrew titles) locks the gameplay to the NMI rate, and PAL has only 50 NMIs per second, as opposed to 60 on NTSC. The audio pitch will also always be wrong, since the CPU (where the APU is) clock is different. This is the BEST case scenario though, since it's also possible you'll get graphical corruption that can render games unplayable.

Quote:
If they run at incorrect speed it might be better to just get NTSC NES and mod it instead.

I just imported an AV Famicom myself, instead of trying to mod anything. They weren't particularly expensive a few years back (I was only screwed by the import taxes imposed by my country).

Quote:
Can a PAL TV (if TVs even have regions) handle NTSC signal?

TVs certainly do have regions. Newer models are more likely to be able to handle whatever you throw at them, older models used to be less versatile. Most HD TVs handle retro video game consoles like shit though.


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PostPosted: Thu May 24, 2018 2:48 am 
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tokumaru wrote:
I just imported an AV Famicom myself, instead of trying to mod anything. They weren't particularly expensive a few years back (I was only screwed by the import taxes imposed by my country).


This option could be better since most games were released in Japan anyway. Lastly, I'm assuming flash carts can't adjust the speed either.


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PostPosted: Thu May 24, 2018 10:48 am 
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SusiKette wrote:
Can a PAL TV (if TVs even have regions) handle NTSC signal?
The vast majority of PAL TVs seem to be multi-standard, supporting PAL, PAL60, and NTSC. Hopefully your owner's manual will verify if yours is.

SusiKette wrote:
Lastly, I'm assuming flash carts can't adjust the speed either.
Correct. The speed of the gameplay is entirely determined by the NMI rate and the specific software running on the cart.


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PostPosted: Thu May 24, 2018 12:53 pm 
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Unless your CRT is some old no-name brand, there's a very good chance it'll support both 60hz and NTSC. And if it doesn't you can probably get a new, much better one for free. Hell, even top notch B&O CRT models are regularly changing hands for just a few bucks around here.

SusiKette wrote:
The speed they run at is what I'm mostly concerned of. If they run at incorrect speed it might be better to just get NTSC NES and mod it instead.

100% absolutely yes!
There's pretty much no reason to even own a PAL NES except from the few select PAL titles you've already ended up with that are actually correctly optimized for PAL speed.
I'd vouch for the AV Famicom as well, as you don't need to mod composite video into it as you would with a US Top Loader NES.

Quote:
I'm assuming the PAL NES power supply works for NTSC NES as well. I doubt they have different output specifcations.

Yes, to my knowledge all PAL and US NES models use the same specifications for the power supply. Japanese models require DC however, so don't connect a European PSU to any kind of Famicom. (though the other way around would probably work - I use the same unoriginal DC adapter for all of mine)


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PostPosted: Thu May 24, 2018 2:08 pm 
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Sumez wrote:
There's pretty much no reason to even own a PAL NES except from the few select PAL titles you've already ended up with that are actually correctly optimized for PAL speed.

Or, if you develop homebrew games, for testing your software on a PAL NES.


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PostPosted: Thu May 24, 2018 5:59 pm 
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I'm not 100% sure right now because it's been a while since I last used my AV Famicom, but I think it works with a Genesis power supply.


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PostPosted: Thu May 24, 2018 6:40 pm 
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Correct.

The Sega MK-1602 power brick for a Mega Drive or Genesis model 1 or Sega CD supplies -9 V or -10 V DC ... at up to 1200 mA. The 3025 for the Master System is similar, but rated for only 1000 mA. Both the Genesis and Famicom require 9-10 V DC with center negative polarity, but the regulator in an NES Control Deck contains a diode bridge that rectifies 9-10 V input regardless of polarity. So take your 3025 or 1602 (or a CE marked substitute), put white-out on the "Ge" and "is", and you have a working replacement for the NES-002 or HVC-002 power brick. But if you don't already have one, make sure to buy the 1602 subtype that matches mains power in your area (120 V ~ vs. 220 V ~).


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PostPosted: Fri May 25, 2018 11:39 am 
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I don't think it was mentioned here yet, but one use for removing region lock on PAL NES is the ability to play both PAL-A and PAL-B games. I wasn't even aware of that there are "sub-regions" in the PAL region code until now. I received my Mega Man cart today and when it was constantly resetting I decided to make sure it was actually a PAL game. The game cart was PAL-A cart (UKV) and my NES is PAL-B (SCN).


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PostPosted: Mon May 28, 2018 2:12 am 
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You want to play the European release of Mega Man 1 on an NTSC NES anyway.
Both the game and the music runs at the same speed as the original NTSC version, so if you play it on an PAL console, everything will run too slow.


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PostPosted: Mon May 28, 2018 6:45 am 
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Sumez wrote:
You want to play the European release of Mega Man 1 on an NTSC NES anyway.
Both the game and the music runs at the same speed as the original NTSC version, so if you play it on an PAL console, everything will run too slow.


I actually tested this on emulator by shooting a single shot right after spawning to Cutman's stage and measuring the time how long it took to go off screen. Both NTSC and PAL took 29 frames. The music is just slower in PAL version, but that's just about it. I guess it kinda deceives you as I thought it ran slower until I tested it.

Besides Mega Man isn't the only game I want to play. By having access to both PAL-A and PAL-B games I have a bit more options when buying games. Especially if the game I want is only available as a PAL-A game at a reasonable price.


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PostPosted: Mon May 28, 2018 6:49 am 
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Are you 100% sure of that? I've done the same test, but using Mega Man's walking speed as indicator.

It seems weird to me that they'd change the shot speed, but not optimize the music, which is usually the "easy" one to fix.


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