Will it run on 5v?

Discussion in 'General Discussion' started by ToastBucket, Apr 26, 2010.

  1. ToastBucket

    ToastBucket tost

    The N64. We all love it. But wouldn't we love it more if it could run on 5v instead of 7.4v/12v? Or maybe even solely 3.3v :eek: Once I get an N64 from Jlee I'll play with this but if anyone else can test this before me post results here :awesome:
     
  2. tkh

    tkh Newb

    You can step up the voltage from 5 or 3.3v to a suitable level however it is not very efficient and will take a large hit on battery life.
     
  3. bentomo

    bentomo Frequent Poster

    It needs at the very least 6v, but even then the current draw is a lot bigger.
     
  4. βeta

    βeta ModRetro Legend

    He is talking about bypassing the 7805, I believe.
     
  5. ToastBucket

    ToastBucket tost

    this

    The only problem is that the 12v line goes into a chip and a couple caps before it gets regulated to 5v. I'm going to take off the 7805 and put 5v before and after just to see if it works.



    We can always dream bentomo.
     
  6. You can do it with the gamecube as the only thing that really needs to use 12v is the fan (You don't really need the fan if you replace the heatsink and thermal paste with something better, just don't play it for hours on end)

    The N64, however, I haven't tested it, but I doubt it will work, especially if the 12v line goes into a chip. Usually the chip will have a working tolerance of between 9v and 14v where 12v goes in (again, I haven't tested this) so although you could theoretically get it working at a lower voltage like 9v, it might not work at all at 5v. Even if it works, starving the chip of power might have unexpected results (freezing, resets, lag, etc)
     
  7. LOCtronicz

    LOCtronicz Formerly known as zenloc

    You can power the n64 with a single 3.7v battery cell. But as bentomo stated it would have a higher draw. All you need is the following:

    Little step up from 3.7v to 5v for the video chip. The sound chip also works at 5v so connect 5v to it aswell.
    Switching regulator to get a stable 3.3v line.


    As for the gamecube:

    The sound chip also uses the 12v line. Altough you can power it off 5v not every gamecube board I have done it on likes it. Some will sound distorted. As for the 5v line that is only used for the disc drive motor and 5v controller line for rumble. So if you were to use the step up from above you could also power the gamecube of 3.7v. Ofcourse you need to have a step down from 3.7v to 1.9v and to 3.3v check my custom regulator topic for more info on that. Which is also what I'm going to do in my gcmini. I would also advise to keep a fan for the cube even if you have a different heatsink and add better thermal past it still get's hot.
     
  8. Bibin

    Bibin Frequent Poster

    Zenloc that sounds more like the amplifier that needs 12V, not the audio processor. Try pulling line out from the audio then using your own amp.
     
  9. snowpenguin

    snowpenguin Frequent Poster


    N64 works perfectly with no mods at 7.2+v on the 12v line, this is the usual battery voltage used (7.2/7.4).

    I don't really see a use to running it off of 3.3v, but it would be awesome if it would run on 3.7 or 3.3 as that would mean you could run the n64 with one cell and no stepup.

    As the 12v line draws little of the power the n64 uses, efficiency would not take too large a hit.
     
  10. Basement_Modder

    Basement_Modder He who mods in thy basement.

    Or, better yet, you could get the traditional 2 cells but wire in parallel instead of series, which, if you use 4700mAh or so, would give 3.7v @ 9.4Ah, and would seem to more than make up for the additional draw from the sound/ video chip's step-up card.
    ...but this is only in theory.

    On a 3.7v cell with a full charge (4.2v) the step-up would only be 0.8v, and the reg would draw about an amp for the 650-700mA being drawn by the 5v line.

    The 3.3v would be a bit trickier, as there are no (cheap/ good) switching regs that will accept 3.7v to output 3.3v. That said, you would have to take a PTH08000/ 08080 and step it down from the stepped-up 5v source.

    Here lies the primary obsticle. The 3.3v line (on a rev. 4) usually draws 1.5-1.7A. (1500-1700mA). You would need a step-up card capible of about 3A of draw on the output line (incase the 3.3v line's draw spikes to >2A, which it does do.), which would draw about 4.5A from your battery, giving you just over an hour running the N64 alone on a single 3.7v 4700mAh cell. If you had 2, it would go about 2.5 hours, vs. 4.5 or so when wired at 7.4v (neither of these include a screen.)

    Also, you would not even be able to think about using a PSone screen with this setup, unless you want to be even more ineffecient. (We're talking like 20 minutes of battery life and another step-up card to 6.5v)

    I assume, however, that you would use a 3.5" with this setup. Great. That will draw about 250mA at 5v, and 350-400mA at 3.3v, if you're lucky. Have fun with your uber-small portable that gets 45 minuites of battery life.

    OH WAIT-I forgot! The screen's power draw overloaded th step-up card! Now you need to connect it directly to the battery, causing more power draw! Now you get 35-40 minutes! This is with a jumper pak, no sound, and no controller.

    tl;dr: don't do it.
     
  11. ToastBucket

    ToastBucket tost

    :gonk:
     
  12. snowpenguin

    snowpenguin Frequent Poster

    No.

    Dunno if that's what that rev draws, but, lawl, average n64 draws like 1.1 amps on the 3.3v line. Having the n64 run on 5v is mostly useless unless you're going ni-mh, and if you're going that route, I doubt you care about smallness that terribly much.

    Dunno what 3.5" screen you're thinking of, mine doesn't draw nearly that much.

    That all said, having the n64 run on 5v is mostly useless unless you're going ni-mh, and if you're going that route, I doubt you care about smallness that terribly much. Stepups are inefficient, etc.

    Now, if you could get a 4.2v/3.7v->3.3v regulator and find a way to run the main 12v line off 3.3v, things would be mighty dandy.

    Anyone have an n64 to see what exactly is powered off of the 5v regulator line and the 12v line?
     
  13. Mako321

    Mako321 I like purpale ponies

    doesn't the 5v = 12v line, you're making it really unclear now.
     
  14. ToastBucket

    ToastBucket tost

    The 12v goes into some chips and caps before getting regulated.

    at 3.3v mine will pull 185mA. I think a LOT of BM's numbers are wrong =/
     
  15. Basement_Modder

    Basement_Modder He who mods in thy basement.

    Those were mostly estimates/ IIRC things, not exact. Also, I have had a 3.5" screen that drew that much at 5v. The 3.3v line will always pull at least an amp.