see details in the cpu power supply write
output got so many but i only wan the 12vDC with 9Ampere another one 12vDC is getting 0.5Ampere only.

But in the output got so many wires and colours i dont know which one is 12vDC 9AMpere output.
So how can i know which is the 12vDc with high current?
the output is one got 4 wire to motherboard then another is like 10 or more wires is also connect to motherboard but it is another socket,finally is the IDE for hard disk and cd rom one,
So which one is 12VDC 9 Ampere?
mostly which part of PC are using the 12vDC 9 ampere?

i Can get a DC power supply but quite expensive so wan modify my power supply only for 12vDC high current should be more cheaper

I get this idea is from a hardware seller he want to modify a cpu power supply for me is 12vDC and 8 ampere but the price is RM90 if i buy a DC power supply no need modify 6 ampere is only RM70,the reason that i wan to modify cpu power supply is for save money.
A power supply is cheaper then modify will save more money and get more high current.

Help Sifuu Tell me whic wire is 12vDC which colour is 12vDC.




All the Hardware Pro Help Here
Thank you

9A you crazy bo? need so many A for what?

i am not using for CPU anymore after modify i only take for power up another thing

probably need to run the full fan speed

This post has been edited by E-J@1: Dec 3 2006, 01:11 AM

black and red for the 12V line, at the molex

if ur talking about the 4 pin molex for HDD and CDROM...the red is the 5v

the 12v gets supplied thru the yellow wire.

try use mr google or wikipedia...more info from that u can get

i am modify it for Car amplifier.with fuse 20A
But i hear from someone he say he tried before but soon the power supply broke and burn.is it true ar???
Or got any idea can protect it to avoid the problem?

Squeezing extra ampere from the PSU will lead to early burn of transformer and switching controller.
build a custom power supply which output 12V DC @ 9A would be more feasible

This post has been edited by haylui: Dec 4 2006, 12:58 AM

fren then how to custom it with only 12vDC and 9A?

make new tranformer ??
How to make or ??
A tranformer is it available for DIY,following the ampere that we want ?
Let me know please Thank You

http://ituner.stores.yahoo.net/ac12v9aswpoa.html

buy this

mod the psu for car amp???

where can get the stuff?

no ideal, btw car DC output already 12V +- i think just need modify fuse can jor but becareful o... don't burn your car.

just to save 10-20 ringgit, you go through all the hassle, and also the possibility of your DIY mod not working and blowing things up.

fwush.

me, id rather just pay the money to get something that is guaranteed to work. besides, in the larger scheme of things, i dont think RM70 is that much.

but bro RM70 for 6 ampere T.T"

sometimes half the fun is in DIY, ie like buidlign a rig or oc...n the anticipation of seeing whether ur handiwork will work or not...of coz dont work then no fun

Well, i've done this project before. Using computer PSU for +5V & +12V power supply. It might be easier to work with if you got the old AT power supply. This kind of power supply can simply be 'on' by toggling the switch. As for the newer ATX, you need to find 'power on' cable and short it to 0V(DC ground). Beware that some ATX need 'dummy load' before can be powered up. Failure to do so may damage the power supply or simply refuse to run.

Reference:
http://www.instructables.com/id/E6D9DB9RPPEP286BR9/?ALLSTEPS

fren the diagram are show not clear.
Which cable should put to the fuse place and which for the switch.
the +12dc ,-12dc,+5dc,ground is it are there all using for hard disk and cd rom that one cable?
And where you get the stuff like the red and black plug?
Thank You

i agree, but the TS doesnt appear to be doing it for fun, as his apparent main concerns are the cost, cost and cost. looks to me like a case of penny wise, pound foolish, but thats just IMO.

Ok, let's play safe, shouldn't we ?
Never open the PSU casing and poking around even it's already powered off. My method might be not so elegant, but should be "safe enough" for most people to experiment

1) Please mark your cable with proper label. You can get cable layout & definition from here:
http://pinouts.ru/Power/atxpower_pinout.shtml
http://pinouts.ru/pin_Power.shtml

2) After finish marking, you can cut & remove the 4-pin molex, ATX connector and any unwanted connector. Group & bundle them together based on their function. Eg: +3.3V, +5V, +12V, -12V, -5V, PS_ON, PS_OK(sometimes called 'Power Good'[PG]) and so on so forth. As for 0V(DC ground or DC Common[COM]), try to distribute it "equally" between required voltage. Eg: 1 wire needed for PS_ON, the rest should be divided proportionally between +12V & +5V (also +3.3V if you want).

3) You can use small toggle switch if you want to enable on/off the PSU. Else, just short it to 0V (Tie the PS_ON to 0V). If you decide to use switch, simply connect one point to PS_ON and another point to 0V. Use continuty tester/voltmeter to test the switch connection.

4) Since typical ATX is a switchmode power supply, they need a minimum current load for proper operation(Eg: for LC filter operation). This value ranged between 2% to 5% of full current load. So, depend on how you use your PSU, most likely you'll need dummy load. Typically we use resistor as dummy load. For example, if your +5V has 10A max current, then 5% of 10A is 0.5A. To find dummy load power rating:
Power = Current x Current x Resistance
If you choose 10 Ohm resistor, minimum power rating for resistor is:
Power = 0.5 x 0.5 x 10
Power = 2.5Watt.
Of course if your +5V has higher current(eg: 20A) then, you'll need higher wattage resistor. Eg:
Max current load = 20 A
Minimum current load = 5% of 20 A = 1 A
Minimum resistor power rating = 1 X 1 X 10 = 10 Watt.

5) When finish calculating your dummy load rating. Go buy them at your local electronic store. Make sure you specify:
- Resistance (unit Ohm) (should be exact or with minimum difference value)
- Power (unit Watt) (It's ok to buy higher rating, but the higher the rating, the more it cost)
You can choose to substitute dummy load with some equivalent electrical device. Just make sure it have equivalent rating. Example: Automotive bulb, high power fan etc..
If you choose to substitute the dummy load, always ensure that the substitute can never be removed(Eg: permanent assembled). Or design it to make sure power can never be 'on' when no load(eg: ATX motherboard pin design).

6) Now you got resistor/dummy load in hand, assembled them to +5V and 0V.
PSU ---- +5V cable ----> resistor <----- 0V cable -------- PSU

7) Please insulate all unused cable with proper insulation(eg: insulation tape or heatshrink). Make sure they won't touch any cable or PSU casing.

8) Connect your PSU to main socket and power it on. It should work. Use voltmeter to ensure correct operating voltage.

9) As for the fuse, you can connect it for each voltage you want. Eg:
PSU ----- +12V ------> fuse ----> 12V output
PSU ----- +5V -------> fuse ----> 5V output
PSU ----- +3.3V -----> fuse ----> 3.3V output
As, for the 240V AC side, most PSU already had built in. You "can" open the PSU casing to confirm it.

10) Now to use, simply hookup any electrical device to output voltage, eg: for 12v device, connect it to 12V output(that is output after the fuse).
Eg:
+12V output ------> Your electronic device <-------- 0V --- PSU
+5V output ------> Your electronic device <-------- 0V ---- PSU

Sidenote:
- If you just want single unregulated power supply, eg: 12V, better buy transformer and do full bridge rectification. It's cheaper that way.
- If you want single regulated power supply, the cost for this DIY and buying new one is quite balanced. Cost reduction may or may not happen.
- If you want multiple voltage regulated power supply, eg: similar to lab PSU, then this DIY has bigger advantage and come with cheaper cost.

Good Luck.

Btw, good reading:
http://www.smps.us/computer-power-supply.html

This post has been edited by mokona_modoki: Dec 7 2006, 12:56 PM

THanks Bro.THanks a lot.
i also like to DIY one can save cost second is you can done it with your own right or not??
Anyway THanks You

Yeah, money can't buy experience. I myself also prefer DIY rather than buy existing products. As long as there is satisfaction for the works/projects, than thats good enough