Here is a cheap and easy 3.3v converter!

[bacteria]

I bought two of these off some guy in the USA (I live in the UK) for $13 delivered (about £6.40 ish).

Sony DCC-E230.
Input DC 12/24v
3v output at 1000mA

Anyway, that's what it says on the car adapter.

After reading lots of posts on this forum saying you need 3.3v for the N64 (as well as between 9.7v-12v for the other input) and 3v isn't good enough, I thought I had wasted money on the above car adapter - anyway, took it apart (ignore the fuse, you don't need it in the pic), soldered a battery adapter cable to the positive and negative, applied 12v battery pack to it (I had some regular AA batteries doing nothing at the time), and my multimeter gave a reading of 3.37v - perfect! I then, out of interest, applied a 4.5v battery pack, and got 3.3v again - this means you could, in effect, rig up anything from over 4v to (probably) 24v on batteries and output 3.3v.

Thought you guys might be interested, as there have been many topics on the N64 forum about 3.3v power.

I am in the early stages of making a portable N64 unit. This adapter has the right voltage, my only concern is that it is rated at 1000mA and I read somewhere you need 1330mA - no idea if that means this has enough juice? (perhaps someone can advise). I thought of hooking up to one set of batteries (9 x AA rechargable 2700NiMH batteries) to run the 12v in, a computer fan (to keep the N64 mobo cool) and this adapter for the 3.3v line. Comments??



Deleted link to e-bay site as link is very long (as per a request) - basically, search for "Sony 3v minidisc car adapter" should do it!

[jeroen]

No offense but a lot of people already knew this. What I didn't know was that you can use less then 12v.

[bacteria]

I know people know about car adapters, that is why I bought a couple; there have been various posts about them - however - they tended to report outputting 3v and not 3.3v and people were posting that 3v isn't enough (incorrect video and sound resulting). There have also been comments that whilst some N64's can take up to 5v many don't and some seem to have a tolerance only between 3.2v and 3.4v.

Why I thought this was interesting is that this one outputs the required 3.3v at lower battery inputs (eg 4.5v) and 3.37v at higher battery inputs (eg 12v).

So the other question - is the 1000maH from this adapter enough from a set of batteries as indicated? I have seen posts saying between about 800mah and 1330maH are needed from the N64....

[timmeh87]

sorry for being a unit nazi - but I think you mean just "mA"

anyways, the 3.3v line is the main CPU line. In my own experience it ran down to about 2.9v and I didnt test higher cause I dont like breaking things . Interestingly, undervolting the CPU in this way can save you a few watts of power if you are using a dc-dc converter.

Anyways, the current draw will depend on if the CPU is "thinking" or not. Menus and pause screens arent going to need as much processing power as four player 007.

the 1300mA figure might be closer to "peak" and not representative of the average. Im not entirely sure. The current limitation on the adapter is probably mostly for heat concerns. If the average current is around an amp youd be ok. Or if the theres a large safety margin.

Wost thing that can happen is you blow out the adapter I suppose...

can you tell if its a linear reg or a dc-dc converter?

does it get hot? is there a coil on the board?

[bacteria]

There is a coil on the board. Only tested it for a minute or so to test it - it is designed as a DC to DC car adapter so I would expect it to be fine.

Only going to use my unit as single player.

Going to incorporate a fairly large fan into my N64p, 50mm, only 170mah and extremely quiet (old salvage from dead computer). Fan should help to keep the adapter cool anyway.

[marshallh]

Looks like you are measuring the output voltage without any load. While it ideally would be the same with or without load, there is still a difference (the output might drop lower than 3v under peak.)

If that happens, just use a late-revision (colored case) n64

[bacteria]

I have 3 x N64 units, so have 2 to mod with if I need to. All three have their first 2 numbers on the serial number as "13" so I am hoping they can be RGB rather than composite (won't know until I open one up); someone posted that if this number is "17" or less it can be RGB'ed as it is an older system.

Yes, measured the voltage without any load.

I plan to rig up 2 battery packs:

1)
12v driving : 170mah fan, a car adapter for the 3.3v line, and the 12v line for the N64.
2)
8.5v driving the PSone screen (6 x AA rechargables, fully charged, are 8.45v, not 7.2v).

If the load on the 3.3v line is too much, I will try either just using 3 x AA rechargables, or 6v pack on the 3.3v adaptor. I need to experiment!

[Felino]

Firstly, this is not a dc-dc adapter, its a 3volt reg on a board. Thing is, the 3.3 volts you measured is under no load, under load this is going to be lower, looking at the pic there is no filtering or other protection, so this is a really cheap way of doing it.

Also, why use 15 AA batteries like you stated above? A 12-volt fan will never need the 12-volts, they run as low as 4 or 5 in some cases, when going at lower voltages they will make less noise as well. Also, using this car -adapter is going to be horrible on your batts. The thing is made to be used with a car battery. You are talking 120 amp hour, they are not going to worry about being efficient here.

This is kinda a waste of time. Don't bother, get a real dc-dc converter, and save yourself 15AA batteries. Honestly.

Using a fan from an old computer is probably not a good idea also, with that you will get tonnes of noise, and frankly, you are never going to get a 40mm one in an old PC. Ever.

Lastly, the number of times i say this is geting stupid, i have to make a sticky for this forum. DO NOT USE AA BATTERIES They are never going to supply the current needed, and will enver, i repeat never give you any play time, and this thing you are talking about will weigh a ton. 15 AA batteries, will be over a kilo, trust me. Who wants to lug that around.

Sorry to sound negative, but I am trying to stop you wasting money. Use sub-C batteries. Honest.

-Fel

EDIT: Also, 'sony'? My solder sucker...

[bacteria]

Filino - appreciate your comments.

Fan I was meaning was a 9cm fan, which is totally silent - tried it on c. 7.5v, 9v and 12v. I was thinking of relocating the cartridge slot to the rear at the top and the fan immediately under it - there is just enough space - after all, I will be holding the portable when playing it, so no issue having fan at rear of case. It will also help to keep the cartridge slot firmly in place. I tested the fan, yes it works on 4.5 volts but too slowly for much use - give it at least 7.5v and it works well - lots of nice cool air moving quickly, which is what you need. 7.5v is fine, after all, under this and the PSone screen dies. Other fans I have make a noise, this one is totally silent. This fan should keep everything cool - after all, it kept an old PIII I had cool for a number of years.

Tried to remove the N64 screws as some people indicated, gave up so bought a special screwdriver for it - when I have opened the unit up I will experiment - easy to rig some batteries, fan, etc to the two inputs and test, without doing anything further. Best to do this first anyway.

Took pic of the adapter - uses a step-down regulator by the looks of it, and uses capacitors too on the board. Connecting the rightmost pin to + on multimeter and - on the 2nd left pin gives readout - tried it with no load on a 4.5v, 8v and 11.5v battery pack, each time gave 3.4v reading unloaded, put a 3v torch bulb (yes, I know there isn't much draw but I couldn't think of a device I had using 3v presently with lots of drain - don't flame me!!); gave same result on multimeter. I am fully expecting the voltage to drop to a stupid level when given high load, after thinking of your comments further, however the proof will be in the pudding - might be wrong after all and it works fine - only way is to test it after all - either the N64 boots up and stays on for ages fine, or it doesn't - cut and dry.

I figured I would get the N64 working on batteries, and see what I get. If the N64 boots up, I will use a multimeter to see what voltage I get from this step down regulator, then try a game and do the same thing, then let everything run until it dies and see how long it lasts. If the N64 doesn't boot up because the adapter sucks, the adapter will be binned and I will try something else!! It will be interesting, after all the adapter is rated at 1000mA and fused at 1A. Might be I can play games like Mario 64 but not the likes of Donkey Kong.

I may as well try this experiment, I have a stack of powerful photo grade AA's (2700NiMH) and I have this adapter anyway, so only thing I may waste is time (having fun) - that's assuming it doesn't work of course - if it does work, great! Nothing to lose.

I know your comments on sub-C batteries are correct, however the AA's will allow me to test the unit as it stands; if it works (even for over an hour) on such batteries, it would be easy enough to move to sub-C ones to get more playtime (after all, all tests can be done prior to designing a case to put everything into) - however there is no point spending lots of money on these sub-C batteries and finding I can't complete the project (fried boards, etc) - I have no other equipment which uses this size of battery - that would be a waste of money then!! If I get it working (on test) with AA's, it will certainly work better and longer on sub-C batteries, if I use them. Don't be annoyed by people using AA's, there are many advantages to them - sub-C's are better yes, Li-ion are the best, but dangerous potentially so "not for me".

My design for my N64 portable will be a bit different to other ones I have seen on the forum; I will describe more at a future date assuming I can get everything working in principle ok - no point going into concept details too much at this stage. Good chance I may fail in my project at this early stage after all.

What do you mean by "EDIT: Also, 'sony'? My solder sucker..."?

[timmeh87]

Hm ok I have lots to say but I'll try to be brief...

1) some people might be missing the point of voltage regulators here. The point is that they will always output a constant voltage, regardless of load or input voltage. (obviously thats only if you operate them within their rated operating specs). the voltage from the device in question should /not/ drop significantly under load, and from what I hear it dosent.

1.5) just cause the reg was made to put in a car dosent mean it is crappy. If its a dc-dc it cant be worse than a linear reg. The right part probably costs exactly the same as the wrong part (ie pennies), whats the point of making a crappier product? just cause the power source is infinite dosent mean things are purposely made to be wasteful.

2) the thing on that board looks suspiciously like a linear regulator (not good). you say it dosen't get hot under load (has to be under load)? I say this because I dont see many of the parts required for a Dc-Dc (except the coil). but it could be all inside that chip... I tried searching that model number (lm2979? could you verify that?) but came up with nothing.

3) rechargeable batteries will express a higher voltage (maybe up to half a volt per cell) when they are fully, fully charged, however that is temporary and cells (ni-mh at least) should settle back down to 1.25v each after a few minutes of load. dont expect your 6cell pack to actually have 8.45v, ever, because

4) batteries voltage DOES go down under load, unlike the regulators discussed in 1). this is because there is internal resistance in there, zero current will drop zero volts across it, but the higher the load the lower the pack voltage will dip.

5) when felino was saying not to use AAs, he was trying to tell you that AAs can't actually supply enough current to turn on a n64+screen.

6) but you are using two battery packs, and potentially a dc-dc, so it might work. however most people (including me) advise against using two battery packs. for one thing one of them will always die first (the n64 one). and also:

7) nothing in your portable actually needs 12v. why are using a 12v battery pack? /EVERYTHING/ will run off 7.2v. the higher the voltage you give to the n64's 12v line and the screen, the more power you are just wasting. but you cant use one 7.2v (6cell) AA pack of course (See 5)

8 ) you are still confusing mA with mAh. one is like speed, and the other is distance. (km/h vs km. the second one is multiplied by hours)

9) if you need a power source for testing, dont screw around with rechargeable batteries. rig yourself up a bench power supply from an old computer. I did it, most useful thing I ever made. you get 3.3, 5, 7, and 12v sources to play around with. (you can make other combos too i just listed the useful ones). theres 100 articles on doing it, it takes about an hour.

http://www.instructables.com/id/E6D9DB9RPPEP286BR9/

10) could you please shorten that link in your first post?

ok Im done for now I think. happy hacking.

[bacteria]

Thanks for the reply timmeh87. Comments please on point 3!!

1) That was my understanding too.

1.5) Indeed. If it works, no issue.

2) No idea how hot it will get under load, I will be using a large (9cm) computer fan to keep everything nice and cool; hoping it will remove the need for heatsinks by using a good fan instead.

Writing on the regulator (my camera is bad at closeups):
JM34AL
LM2575T
-ADJ P+

3) Ok, I was concerned that as the PSone screen doesn't like going over 9v that I could only use 6 batteries (fully charged are 8.45v), if they are rates at 1.2v each = 7.2v. I thought if I put in 7 batteries (7 x 1.2v = 8.4v) that 7 x fully charged batteries would be about 9.9v and blow the PSone - is that right? Please advise!!

4)

5) I know that, I discovered it in my BigBoy Advance project - after about 5-10 mins the power drained, the batteries got extremely hot. That's why I used 2 battery sets (one for PSone, one for Transformer) - same principle for this N64 project. I found in this configuration that the batteries didn't even get warm and I got about 1.75 hours playtime - using a mix of 2500NiMH and 2600NiMH batteries (equivalent of one battery pack of about 5500NiMH). Also, with the N64 project, there is very little draw on the 12v line a lot on the 3v line and very little with the fan - so these three items can go on the same battery set, and another one purely for the PSone screen.

6) Indeed, once proof of concept is done, I might well go for the sub-C cells and put everything onto it - unless the overall weight is similar or there are issues with battery height. Yes, one battery set will die first, quick to put right.

7) I take your point on board.

Thanks. My electronics knowledge is improving in bounds, but there again it was very minimal until recently!!

9) Interesting, but I wouldn't play with one of these things, they can store a considerable amount of electricity after a long time. I once took apart an old camera which had been doing nothing for a while and got a sharp electric shock from it - wouldn't want this from an old computer PSU!

10) Done it, as you requested.

[timmeh87]

3) Ok, I was concerned that as the PSone screen doesn't like going over 9v that I could only use 6 batteries (fully charged are 8.45v), if they are rates at 1.2v each = 7.2v. I thought if I put in 7 batteries (7 x 1.2v = 8.4v) that 7 x fully charged batteries would be about 9.9v and blow the PSone - is that right? Please advise!!

9) Interesting, but I wouldn't play with one of these things, they can store a considerable amount of electricity after a long time. I once took apart an old camera which had been doing nothing for a while and got a sharp electric shock from it - wouldn't want this from an old computer PSU!

2) I asked about heat to see if it was a linear or a switching regulator. Quick part number lookup reveals that it is indeed a switching reg. the efficiency looks like its around 80%, which isnt bad but isnt great. the 1A limit seems to be strictly imposed, there is a "current limit" module grouped with the "thermal shutdown" module in the block diagram.

http://cache.national.com/ds/LM/LM1575.pdf

3) is a point that has actually been discussed before. Im not exactly sure what the consensus ever was. It seems a bit sketchy to be using a 7 cell pack for the reason that you stated. I believe the point is moot anyways, since it will work fine with 6 batteries, right? what did you need to use 7 for? AFAIK the screen runs fine on 7.2v.

9) aye, it can be a bit shocking to find a charged capacitor (pun intended) but you can just go short them all out with a screwdriver or something. In my own experience the caps in ATX power supply dont seem to stay charged. Cameras tend to purposely isolate charged capacitors to use with the flash; in power supplies for the most part they just drain into whatever is being powered. I think.

[bacteria]

Thanks for your reply timmeh87, appreciated; and for taking the time to look into this.

I looked at the pdf you listed, I don't understand much of it, but you indicate it is ok, so that is fine by me. is its output enough for the N64?

Reason for 7 batteries - if you recharge 6 batteries, they hold about 8.45v. As you say, leave them for a short while (day or two) they reduce to about 1.25v or thereabouts. This reduces them from about 8.45v to 7.5-7.7v. This is fine, but means they don't last for long before there isn't enough voltage to power the PSone screen (tried this); in contrast, freshly charged batteries give their maximum playtime.

My logic is this (please comment): if you intend to play your games system immediately after the batteries recharge, you are fine with 6 batteries. If you are happy to use batteries charged a day or two before (no issue if you have many of these things anyway), then you would be better using 7 batteries (giving about 8.8v instead of about 7.5v). Best to use a multimeter first to find a set of 7 batteries which give under 9v to protect the PSone screen. 7 batteries would not only give maximum playtime, but, in theory, give 1/7th more playtime too - if you get for example 1.75hours on freshly charged AA's, the extra battery (7th) might raise this to about 2 hours, ie extra 15 mins playtime (is this right or am I talking waffle)?

This question is relevant to AA cells, or sub-C cells after all. For purpose of testing, I will be using 12 x 2700NiMH AA's (2 x 6 battery packs); which would be the equivalent of 6 x sub-C 5500NiMH (as the PSone will be powered with one AA set, the other set for everything else). Yes, using sub-C batteries is better, and lighter and smaller in a final project (I just did some research), but overall power would be similar in either combination.

Another question - what sort of LED would you use to alert you to the fact that the batteries are about to die - would be useful to have this incorporated!

[Felino]

You aren't listening to eithe of us, and we both have extensive knowledge in electronics. Please listen to us in this.

Firstly, you can not, i repeat can NOT use AA batteries, they will NOT supply the current to wither devices, and charging 7 AA's is not fun. Use a 7.2 volt pack like everyone else. The reason yur batts are getting hot is you are drawing WAY to much current from them, and are damaging them..

Secondly, mixing battery types is not a good idea either.Also "using a mix of 2500NiMH and 2600NiMH batteries (equivalent of one battery pack of about 5500NiMH)" yet again is not true. Please read up on things before you say them.

Thirdly: What you would have found in a camera is around 400 colts, not fun, but i am making a coil gun so that sort of shock is normal, now i wear gloves, but still its hard not to get shocked. You get over it.

Fourthly, you can not just use an led to indicate vltage, at the minimum you would need a resister and probably a small circuit.

Ask us before you buy stuff.. it will save you money in the long term.. honestly man.

-Felino

PS Spell my name right will ya?

[bacteria]

Felino - I am listening to all comments. You made reference to hot batteries, which I stated above is not correct - two packs keep very cool during constant use (on my previous project); and the fan (reference to your previous post) is virtually silent so is not noisy (you also didn't read this - yet you made a reference to "listening") - and you can use these batteries to power a PSone screen (you said "either"), I did so before - ok sub-C are better of course, but anyway - I was talking proof of concept at this stage.

Sorry mate, appreciate the spirit of your comments, but you come across rather rude in your posts; I doubt you mean to be, but you do. No-one knows everything, new people to a scene need encouragement, and anyway, they can often come up with new ideas and improvements as they think about things in a different way and bring their experiences to use. Anyway, made my point, if you don't like this post, re-read yours and imagine how yours came across to me. Rant over.