N64 power question.

khaag · Post by **khaag** » Thu Dec 28, 2006 12:02 am

According to this diagram:

It says there is 12V power input as well as 3.3V power input. If I use 1 7.2V RC battery, and the dc-dc converter, will it power the N64?

doctorjames · Post by **doctorjames** » Thu Dec 28, 2006 12:28 am

Yes that will work, because the 12 volt input runs to a 7805 on the N64. So anything from 7 to 30-something volts will work.

Neildo_64 · Post by **Neildo_64** » Thu Dec 28, 2006 3:00 pm

Nice choice on the diagram.

khaag · Post by **khaag** » Thu Dec 28, 2006 10:59 pm

Yes, its a very nice diagram.

codeman · Post by **codeman** » Fri Dec 29, 2006 5:11 pm

So...i've seen this everywhere, that the 12v line only powers a 7805. After a quick look at the motherboard it looks like the 12v line might also drive the audio amplifier. But anyway...has anyone tried removing the 7805 and using a second DC-DC converter to drive the 5v line? It would have a much lower dropout voltage, and the system would ultimately run for a longer period of time on the same batteries. (well, depending on the discharge voltage curve) Has anyone tried that, or at least thought of it?

Post by **marshallh** » Fri Dec 29, 2006 7:30 pm

I've thought of it, but the 7805 only runs the audio/video DAC and little else. The draw is so small I don't think anything other than linear would be needed. It also works down to voltages > 6.5v in my testing. I guess the DAC isn't very picky about the tolerance of the 5v.

ATOMICMAN · Post by **ATOMICMAN** » Fri Dec 29, 2006 11:22 pm

marshallh wrote:I've thought of it, but the 7805 only runs the audio/video DAC and little else. The draw is so small I don't think anything other than linear would be needed. It also works down to voltages > 6.5v in my testing. I guess the DAC isn't very picky about the tolerance of the 5v.

considering how power hungry the 64 is i think even a small increase would help even if it meant a few more minutes of play time since the damn things dont seem to get more then like 2 hours of play time. its not like its all that expensive (since you can get the freebies) and doesnt take long.

timmeh87 · Post by **timmeh87** » Sat Dec 30, 2006 11:31 am

most of the power hungriness is the 3.3v line (the cpu) and the screen. the 12v line dosent suck much power.

id be worried about powering the DAC with a dc-dc, because you might find you start having the audio equivalent of the 'diagonal line problem'. dc-dc converters can be pretty noisy

codeman · Post by **codeman** » Sat Dec 30, 2006 5:14 pm

They can be noisy, but under lighter loads they tend to be ok, and the 12v line doesnt draw much current. I might just replace it with an LDO linear regulator. I just dont want the stupid 12v line to be the reason i dont have the longest battery life possible.