This page is a mirror of Tepples' nesdev forum mirror (URL TBD).
Last updated on Oct-18-2019 Download

US NES - AC adaptor polarity

US NES - AC adaptor polarity
by on (#58949)
Can someone with a US NES tell me the polarity of the AC power adaptor?

I made the mistake of not checking once before. :(

Thanks

by on (#58955)
Depends on when you're asking. It changes every 1/120 second (1/100 second in Europe). :)

by on (#58956)
But which line is hot and which neutral?

by on (#58964)
Neil the nes has a rectifier inside so you can just plug in any polarity.

by on (#58966)
tepples wrote:
But which line is hot and which neutral?

The output of the adaptor is from a transformer, so they're both isolated. And on the NES, they go into a rectifier, so they have the same characteristics.

As for using a DC adaptor with the NES, the main problem I've had with some is excessive hum. I believe a Sega Genesis adaptor works fine though. I'd avoid using over 9V though, as it'll heat up the regulator in the NES more.

by on (#58981)
Heh, thanks gents. I was just being cautious because I blew up my Famicom AV last year by having the + and - the wrong way about (one of those multi-volt AC adaptors).

I shall plug it in with confidence :)

by on (#58987)
Hmmmmm. What does a blinking power light mean?

I assumed my PowerPak would work on a Famicom or a (US) NES - am I wrong?

Or is it something completely different that causes the blinking?

by on (#58989)
Blinking power = problem with CIC connects to cartridge, probably due to dirt, etc.

by on (#58990)
Doesn't the PowerPak use the ciclone? Hit the reset button a few times to change its region. Battle Kid power flashed a lot when I first got it.

by on (#58991)
blargg wrote:
Blinking power = problem with CIC connects to cartridge, probably due to dirt, etc.


Hmmmm. The Ebay shop said it's had a new 72-pin connector (and it looks new from looking at it).

by on (#58993)
What a dunce.... it was the Ciclone thing. Hit RESET a few times and it's all working now :)

by on (#58995)
So I guess a game designed for a board that uses CIClone should say something like this if it detects two resets before the title screen:
Code:
BLINKING?

IF YOU JUST BOUGHT THIS
GAME PAK, TRY PRESSING
RESET A FEW TIMES.

OTHERWISE, CLEAN THE
GAME PAK'S EDGE CONNECTOR
WITH A COTTON SWAB.


by on (#58997)
How about flashing a graphical depiction of how to disable the lockout chip in the NES.

by on (#58998)
I kinda like having an obvious warning if your cartridge connection may be bad. That way you don't get an unexpected crash later.

by on (#59046)
This topic is useful for me because my adapter got fried.

I found an adapter that was very similar but I think it had move voltage than the actual one.

by on (#59051)
blargg wrote:
I believe a Sega Genesis adaptor works fine though. I'd avoid using over 9V though, as it'll heat up the regulator in the NES more.

I used a 9V MK-1602 Genesis adapter for a while when my original broke, and never had any problems.

Be careful, though--for some reason, Sega also made 10V (MK-1602-1) adapters with the exact same housing/plug. I dunno what model of Genesis they correspond to, or if the extra volt even matters, but it's something to look out for. (Fortunately, the 10V model is a perfect match for an AV Famicom! :D)

by on (#59060)
Generally AC adaptors aren't regulated anyway, and rely on the voltage drop under load (without load, they often measure 11 volts or more). AC-output adaptors are virtually guaranteed to be unregulated. So the main effect of a higher voltage on many things is more heat dissipation from the regulator (newer ones use switching regulators, which are much more efficient and thus won't dissipate much differently in either case). I can't say for sure, but I'm pretty sure the NES doesn't use any of the unregulated 9V. I try to run mine with the top cover off though, because I'd rather it run as cool as possible. The regulator gets quite hot as it is.