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how to increase wattage/amp output of a power supply? Answered

Hey everybody im back with yet another question.

I have here a adapter for a motorola cyber surfr wave, i intend to use it as a sort of pico psu, since it outputs 5v and 12v. the only problem is that I dont think it supplies enough current or amps to meet at least a 145w psu's equivalent.
I would also like to know what resistor or voltage regulator to use to get 3.3v.

the 145w supplies:
+12v 4.2a
+5 18a
+3.3v 13a
-5v 0.3
-12v 0.8a
+5vsb 2a

the unknown motorola supplies:
+5v 1.5a
+12v 0.75a

does it need -12v, -5v and 5vsb for the computer to work? does a picopsu supply those?
I just need to switch the main transformer with one from a decent psu right? then the wattage will be increased?
If i cant, how can i make a picopsu? i cant order online and have a extremely limited budget.

there is a picture of the insides as well



Best Answer 7 years ago

That won't put out much more than 20 watts I bet. (8 + 7.5). You cannot even remotely expect it to put out 5-10 times as much power wiyh ANY diy mod you can fathom.

You need to get a power supply. There are DC-DC atx power supplies that can take a high current dc source and split it out to run whatever.

Yes, your motherboard REQUIRES ALL the voltages spit out by the psu.

is there any way that i could minimalize the psu?
maybe i could remove it shell, machine new heatsinks, and make a new shell that is a smaller form factor? I dont really want it to be inside the case of my computer, i am trying to build essentially what you would call a game console, but to keep it small i would need to either get a extremely small psu (almost impossible) or get an external one.

i am thinking of making a power brick style external psu then, making the psu pcb as small as i can get it, (ie: the height of it) and putting it in a new enclosure. I would still need to have the grounds solidly connected, but a new, smaller shel would work nicely too, right? I know it sounds like a stupid idea but i really want it as small as humanly possible, i cant afford those fancy pico psu's.

I have a playstation 2 that i can rip the psu from, but from reading with a multimeter it looks like it only supplies 12v, so thats not an option is it?

also, if i post this project in the forums, do you think i would get lots of help? or should i post it on another site?

You can buy something like a laptop (or ps2 if its adequate) power supply, and then an adapter that spits out the required voltages to the motherboard's atx power plug. Again the search term is something along the lines to 'dc atx power supply'. You supply it with dc and it supplies the motherboard with the required power.

Lastly, again, you cannot turn 50 watts into 100 watts, it is MORE POWER, so you need a bigger power supply than the computer needs.

Last case scenario, buy a laptop.

aahh,but your last case scenario might not work for my requirements, considering i want to build a game console with the hardware that of a pc. With a laptop in order to get the video memory and cpu speed even it would cost me some money, too much for this real-low budget project. I will see what the wattage is for a ps2 power supply, if its low enough i will use that and a dc atx converter, if its not good enough i will need to make a external power supply from an existing PSU, i have minimalized a psu before, but because it was of such a low quality (and i forgot to keep the mosfets separate with insulating pads) it blew out destroying one of my small motherboards. it was okay since it used old slow sdram though. I am currently running a 1.6ghz pentium 4, a 256mb ati radeon hd2400 pro, and windows xp on just a 145w psu, but i think i might need more wattage if i want to play games like flatout or trackmania.

I would greatly appreciate it if there was a how-to for making a dc to atx converter, that would help me stay in my budget even easier, i am going to google it and i might turn up some results. wish me lots of luck!

so frollard, what resistor might i want to use to get 3.3v from 5v?
also, how do i get -12v from 12v?
i was looking around on the web and to me it essemtially looks like the power wires are pretty much just connected to their respective pins after being converted to the correct voltage.
I am not sure if -12v is necessary though, because i did have a older board start up through the at (?) connectors without the -12v or -5v. (i am unsure what the connectors are called, this motherboard was the kind that had a psu that started from a switch connected to the psu, not the motherboard. the plugs were 6 pins each. I noted that none of them supplied 3.3v, there must be a 3.3v regulator on the board?) the motherboard didn't go past post though, maybe it was because i was using those old connectors and a 256mb video card, or the -12v and -5v was missing. it still went into the bios settings though.

so what im asking is:
-how do i get 3.3v from 5v? and is there a 3.3v regulator on the older board that i can use?
-how is the -12v line created?
- -5v isn't in a standard 20 or 24 pin atx plug, its not necessary?
-is a picopsu's board as simple as it seems? just wires, some strange black square things and plugs and fuses?

i have uploaded some pictures of picopsu's i found on the net. what are the square black things on the two sides of the board and what do they do? (3rd pic)


the regulators are cheap, easy to buy, but really for a project like this, you won't be running a gaming rig:
a) on a picopsu
b) on 120 watts.

A good gaming system runs 300-1200 (extreme case) watts.

I have a 'gaming' end laptop, and it pulls 90 watts on all 'mobile' components. regular case size components draw huge power.

As for reversing the voltage to have a -12 volts you need some smarts in the plug to do the conversion. There is no easy way to just invert the voltage on a common ground.

ok then, i'll just recase the original psu so it looks good outside the shell of the pc, I know that at least that can be done, I'll just need a printer cord or something...

printer cord? You need proper power cables.

gaah, im running out of ideas here. why wouldn't the printer cable work? are the wires too thin to carry that much current?

I have only one idea left- Create a power supply that connects to the side or pack of the system, with a full power supply inside. i really wanted to do an external power brick type thing though, since with my design there isn't any space for a psu inside the unit.

is there any kind of cord that i can use that is long and has at least 30 wires inside it and isn't too thick?

computer psus need to move a lot of power. a printer cable is designed for low-loss transmission of VERY LITTLE power. Power supply wires are thick to reduce the voltage drop over the wires, since low voltage dc is more succeptible to those losses.

I'm not trying to shoot down your idea, but you MUST take proper electrical design into consideration or you'll let the smoke out, like your last psu.

Miniaturize, fine - but use the same (or better) gauge wire.

ok so one last question (i think)- can I use just one black wire and one red wire and one orange wire, etc. instead of all of the multiples of one color? or would i need a higher guage wire for that too? i think im just going to make a power supply that pretty much can be separated from the device for moving it from place to place. i wanted to make it more or less portable so that i can take my pc games and scores to friends' houses if i wanted to play there. This is proving to be more difficult than i expected!

The power supply can inded be separate, and often is - just use an online lookup table for how much power you can put through various gauges of wire, and start from there. You don't need all 12 +5v lines, you can just have one beefy one, and split it once its inside the case.

i think im going to need a new video card though. my motherboard uses agp as its primary and the pci card i had, the drivers for it werent installing (thanks ATI), so i installed my 32mb (will be upgraded) video card and the computer has been freezing and the vdeo card isn't smoking but it is generating a smell...

i will also have to replace that 145w PSU...

PS i am using a 145W psu, but i am going to see if i can get something more powerful, It has wifi and a video card and doesn't seem to be struggling though...

I could also just use the 12v line and then use voltage regulators or resistors to get the 5v and 3.3v.