How many milliamps does the NES main board receive when being powered by a stock official wall wart? I have looked all over and can not find a rating listed anywhere.
Are you asking how many millamps it draws from the 5V regulator? What do you plan on doing?
The stock adapter says it's rated for 1.3 amps. I don't know how high it goes most of the time, though, probably much lower than that, but it puts an upper bound on what you should try.
The RetroVision cartridge takes an original Gameboy and runs that from a cartridge plus interface logic. Not sure if that helps to determine how much amperage you have to work with though.
In addition to the NES mainboard, the power adapter supplies power to the bridge rectifier and regulator, both of which use (waste) a significant amount of power.
The regulator also likely has plenty of spare capacity for powering more things, and it and the power adapter can be pushed beyond their specs, so that doesn't give us much of an idea of how much the mainboard uses.
These distinctions are why I'm curious as to the motivation behind the original question, what the poster plans on doing with this information.
What I am working on is running the board from a USB wall plug, and I want to make sure I am not pushing too much amperage to it. Could anyone with a stick power brick and an ammeter measure it for me? I would prefer to match spec if possible. I have a few plugs to choose from,m and the one that is physically smallest does 5v DC @ 1.0A.
I agree that the stock power path is terribly inefficient. 9v AC > voltage regulator > 5v DC. Why would they do that? BTW, the Famicom lists only 4v on the sticker on the bottom. Can the NES run in 4v too?
The 7705 regulator needs at least 6.5VDC in input to correctly output 5VDC at it's output, and there is a diode rectifier before it that will probably drop around 1.4V. Therefore the NES could probably be powered at 8V DC, or 5.7V AC. I have not tested this though.
My final objective is to entirely remove the RF circuit from the console. Deck will be nodded for Stereo AV and powered through a USB B type jack.
If you're capable of doing that, don't you already have the proper tools to measure current? Why wait for an answer from one of us?
Sadly, I have only 3rd party wall warts, and my multimeter doesn't measure amperage. Gotta buy a nicer one soon.
Quote:
Deck will be nodded for Stereo AV and powered through a USB B type jack.
The NES can't be in Stereo, ever.
All those so-called stereo mods are shit. They either send trebble to one side and bass to the other, or sends Square + noise channels to one side and triangle to the other.
The NES console and games were designed to be in mono, and this can't be changed by a mod.
This post implies that the toploading NES-101 powering two ROMs and no mapper hardware only consumes 390mA. More will be needed for games with ASIC mappers, although I don't know how much. I also don't know how applicable this is to a front loader.
I run my Famicom directly off of an Apple USB charger, bypassing the regulator, as that USB charger in particular is very well regulated and stable. I can tell you my Famicom in this fashion draws less than 500mA, even when running games with expansion audio that may draw more power.
My Sega Genesis and Super Nintendo have been retrofitted with a similar setup, but with a 1A USB adapter, also very stable. No voltage regulators, very stable 5V.
Here is how it is on the Genesis:
mikejmoffitt wrote:
I run my Famicom directly off of an Apple USB charger, bypassing the regulator, as that USB charger in particular is very well regulated and stable. I can tell you my Famicom in this fashion draws less than 500mA, even when running games with expansion audio that may draw more power.
My Sega Genesis and Super Nintendo have been retrofitted with a similar setup, but with a 1A USB adapter, also very stable. No voltage regulators, very stable 5V.
Here is how it is on the Genesis:
What is the jack to the left of the USB?
I measured the current draw FROM the 5v regulator at one point. Don't remember what it was off the top of my head how much it was. If you diligently search my posts I think you'll find it. I only found a post where I claimed 'couple hundred mA' which is about what I would expect from the 5v line. I've actually still got a jumper installed to measure it again if needed that bad, being a little lazy at the moment and don't feel like taking the screws out to gain access and remeasure it...
As for voltage I have ran my NES down to 3.3v without issue, it started to freeze around 3.15-3.2V. The colors are darker though when running at lowered voltages.
blargg wrote:
Undervolting the NES!
Yeah I actually was doing it for some prototyping using a 3.3v CPLD that wasn't 5v tolerant. It was great fun and made my life much simpler without a completed PCB at the time
pemdawg wrote:
mikejmoffitt wrote:
I run my Famicom directly off of an Apple USB charger, bypassing the regulator, as that USB charger in particular is very well regulated and stable. I can tell you my Famicom in this fashion draws less than 500mA, even when running games with expansion audio that may draw more power.
My Sega Genesis and Super Nintendo have been retrofitted with a similar setup, but with a 1A USB adapter, also very stable. No voltage regulators, very stable 5V.
Here is how it is on the Genesis:
What is the jack to the left of the USB?
There is no USB... The USB parts are internal. The IEC plug on the right side takes a standard PC power cord which feeds mains voltage into the internalized USB adapter.
mikejmoffitt wrote:
pemdawg wrote:
What is the jack to the left of the USB?
There is no USB... The USB parts are internal. The IEC plug on the right side takes a standard PC power cord which feeds mains voltage into the internalized USB adapter.
I think he was asking about the EXT port and the RF switch next to it.