Making an DC-DC power supply

**Stingah** · 06-01-2005, 06:16 PM

A guy told me that i could make myself a DC-DC power supply with some easy modifications. Is this even possible? The power supply originaly run on 230 volts but i want it to run on 12 volts.

The reason I am doing this is that the ******* inverter (DC-AC) was the cause of the flickering on the monitor. Anyone maybe know how to fix this? The electrical noise from the inverter has to go trough the powersupply, in to the gfx-card and in to the monitor. I tried with two diferent computers and got the same result. But when i removed the converter the flickering stopped.

I would realy love to get some respons on this mather, because I am going to tare my hear of soon.

**wizardPC** · 06-01-2005, 06:29 PM

What screen are you using?

**Stingah** · 06-02-2005, 06:38 AM

Originally Posted by wizardPC

What screen are you using?

It's a sharp monitor. Pictures: http://www.mp3car.com/vbulletin/show...777#post517777

**evandude** · 06-02-2005, 07:49 AM

There was a thread on this subject not long ago. The end result was that it is NOT worth bothering trying to convert an ATX supply to run on 12v... if it were even possible (not likely) it would take a lot of work and probalby cost more than just buying a DC-DC.

**Rider** · 06-02-2005, 08:01 AM

It is possible...

This is translation from Slovenian forum:

In attachment you have schemes...

Pull out everything that is marked on "shema2",Pins 9 and 10 are originaly on the same GND. Separate them and connect it to transistors , pins 10 and 8, That are originaly outputs connect on +9V og 7809 regulator.

Part of sheme with 78L05 Is not in evera supply, If you haveone, live it in and connect on it's input, output of 7809. In that case you only need to buy 7809.

Two IRF 540 are enough, But i've put 4 on cauce of greater power...

I didn't try to make it yet, but i know that supply is working

**Gobby** · 06-02-2005, 08:10 AM

Sounds like a hell of a lot of effort when the M1-ATX, Carnetix etc are around and pretty cheap.

**Rider** · 06-02-2005, 08:16 AM

It is cheap if you live in countries where they sell those things... I live in Slovenia and here there we can't buy nothing of this (yet) to import to our country it's juts to expencive...

Let's say - modding AC-DC in our country costs about... 20Eur!! Do you get 200W power supply for that money? If you do (Even for 40Eur) i'll buy it immediatly (If there is someone who can send it to me)

**Gobby** · 06-02-2005, 08:20 AM

If it was possible to do easily, I'm sure more people here would have done it.

**evandude** · 06-02-2005, 08:28 AM

from that little excerpt you showed me Rider, it sounds like you only implement the lower voltage rails of the power supply... the 5v rails and other lower rails most likely run straight off the 12v rail, which would allow you to connect an external 12v rail and then the lower voltage rails could run off of that. Essentially you would have a very large, very crappy version of the PW200 DC-DC.

However, you would have to build a separate DC-DC to supply 12v to it, because otherwise it wouldn't survive crank, plus you'd be supplying between 11 and 14+ volts to your 12v rail, so anything using the 12v rail would NOT be happy.