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Vedran

ATX power supply

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Hello! :D

I have one old ATX power supply from my old PC, it is 230W and it is broken! I will to fix it so I am wondering can i somehow add some kind of voltage regulator and regulate voltage ( for instance 1-12V)?
Anyone has shematics of ATX power supply?

Thanks! ;D

Vedran 8)

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http://computer-power-supply.globalspec.com/Industrial-Directory/atx_power_supply_schematic_diagram
Probaj ovaj sajt Vedrane. Cisto za svaki slucaj reci cu ovo i na engleskom...
Try to find something on this web site.
U alredy hev +5, -5, +12, -12 on power supply.
Its esay to regulate voltage if not need hi current. U can get that by puting a primitiv pot. If you need hier current, u have to incorporate little compicated unit...

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Thanks for link!

Hvala za link, sada sam na faksu ali kada budem imao više vremena kod kuće prućit ću to malo detaljnije...

Gdje bi konkretno trebalo spojiti potenciometar? na sam izlaz? kako se uopće pali ATX napajanje, gdje je kontakt koji treba prebrikat da se upali!

Puno ti hvala!

Thank you very much!

Bye ;D

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Guest Yevgenip

Oh, He speaks Ukraine!!!
I'll try to translate, since I speak russian:

He sais thanks for the link and that he will do something with the fax once he has those components.

He also asks where exactly do you need to solder the potentiometer? On the 'Izlaz'? (I don't understand the next bit, something about where to put the ATX).

Thank You!

J'aime ce forum!!

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Hey guys,

Sorry I was speaking Croatian... I just found shematic for ATX power supply and going to repair it. There is also pinout for ATX so now I know all that i was interested in. I also find some interesting links on internet about how to make your ATX PS handles more current!

Thanks all of you! Bye! ;D

p.s. I attached shematics in case somebody else was interested or has old atx PS at home!

atx.pdf

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Hey!

You see my fuse is all burned out ;D

I have to replace that green capacitor first but i don't know what capacity is it? I wrote some letters and numbers i can see!

Please help me to recognize, or suggest me what capacitor should i put instead! It is connected between fuse and greatz!

Thank you very much!! ;D ;D

post-207-14279141998459_thumb.jpg

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Hi Vedran,

The fuse looks like it has exploded, there must be a shortcircuit in your PSU. Is the capacitor shorted? Are you sure it is a capacitor? What kind of symbol is there on the pcb under the

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Hi Ante,

There will be many questions and answers here before i fix my PSU!
Yes that is ceramic capacitor like one on the picture but in green color and unknown type (capacity) and i am trying to find that up! Fuse did explode and i also think short cicuit was in that capacitor! I don't know! Greatz is (i didn't know how to say on english) made of 4 diodes turning AC to DC.... you know....( ~ -> - ) :D

I really want to fix it! Should i put any capacitor and try it on?? 8)

bYe ;D

Vedran from Croatia

post-207-14279141998568_thumb.jpg

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Hey Ante hello again,
Yes capacitor is broken! Its resistance is 36ohm and it should be much more. I can also see it has mechanical damages! I want to replace it but i can't see the capacity because it has small "like a hole" damages! When I find out what capacity it is and buy new 5A fuse i am going to try it on!
Thanks!

Vedran

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Don't ground out the PS on unless you are sure. I think there is something in your circuit that is causing your fuse and capacitor to blow. Try this. Unsolder components. Just take them out, except for the rectifiers. You might even cut a trace to isolate the problem. This is going to be major troubleshooting, so use every means possible. Suspect whatever semiconductors you have. I'll take a look at your circuit. This is going to be a soldering nightmare so be careful not to damage the traces. When you are done, you might have to rewire a few things but that is the price you must pay. Just be dilligent. You might try and replace the fuse with a small wire to save you from going through fuses. It may be that the current draw is a little higher than the fuse. Try pulling the parts closest to the fuse as they are most circumspect. Don't bother with the resistors. Good Luck.

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Hi Ante,
Do you think it is C4 on the schematic that has blown? I have never seen a ceramic cap marked 221J before, even a little 220pF cap would be marked 221Z5U or 221COG. A 220nF ceramic cap is usually marked 0.022. I think it is a 220V 5% MOV, which would be Z2 on the schematic.
Maybe someone plugged it into 230V with its switch set to 115V. The peak of 325V would have fried the MOV until it was "well done" and explode the fuse too.
How about testing it with a lightbulb replacing the fuse? If the PSU draws too much current the lightbulb would increase its resistance and limit the damage.

"PS-ON" says on the schematic, "0V run, +5V stop". Maybe this PSU is the same.

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Hi Ante and audioguru ;D

Ok I will try that bulb experiment so we will se what happens. Where should i look for the switch for changing input voltage (230,115)?

On pin9 5V_SB there should be always 5V no matter is PS_ON activated (of course if AC is pluged) and i measure it but it is NULL.

I replaced fuse and as i can see rectifier bridge is working fine... i don't know how to test it more further....

Thanks :D

...:::Vedran:::...

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Hi Vedran,
The 230V/115V selector might not be an expensive switch but is probably just a wire with a jack that plugs onto a pin. The pins should be marked.

You are correct. The schematic shows a separate 5V supply that powers PS-ON, which should measure about 4V. It is powered from the rectified mains. Is it getting power?

Please be very careful, you are working with mains and high DC voltages.

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Hey audioguru,

No i can't see such a jumper wire, but on my PSU there is big sign (only for 230V) so I that isn't the problem. It might be that fuse blowed with my fault, PSU stopped working so I opend it and accidentaly short circuit it when I was testing it. So that you don't be on wrong trace. There is no power on any pinout, it seems it is not getting to the end... Error is somewhere in the middle! ???

...:::Vedran:::...

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Hi Vedran,
The FryGuy has an interesting way to get lots of power.

I don't like to short together the outputs of power supplies without resistor or diode isolation. They won't have exactly the same output voltage so the higher one will "hog" the load current.
I also don't like to short the output of a TTL gate to ground without an isolation (current-limiting) resistor.
His description of PS-ON is the opposite to the description on your earlier schematic. Which way is yours?

It will be very difficult for you to repair your PS unless you have its exact schematic. There are differences between them such as the opposite PS-ON function, and whether the +5V standby comes directly from mains AC (with a small mains transformer) or mains rectified DC (with an HV oscillator feeding a small transformer).

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Hi Vedran,
A Metal Oxide Varistor (MOV) is a voltage surge arrestor that quickly limits a voltage to its rating. Its effect on AC voltages is similar to two back-to-back zener diodes. Its small size limits the amount of time it can withstand an overvoltage condition without damage, so it is used only for arresting short duration surge spikes. It looks similar to a ceramic capacitor but maybe thicker. Sometimes its symbol is a capacitor in a circle. ;D

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Yeah i think that was my mistake!!! I thinh that was burned not capacitor... but i don't know what type should i put????
Look at attached picture on one of my before posts i wrote sybmols I can read, ones I can't read are ?
So maybe that was the problem! Yeah it was thicker than regular capacitor.... It was green.... and it was on AC part of schematic....

Thanks! Bye! ;D

...:::Vedran:::...

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Hi Vedran,
You wrote "221J", which would make it a 220V 5% MOV. It would safely limit voltage spikes on the 115VAC side of the circuit, which is half the circuit when 230VAC is used. Its diameter determines its power handling ability. ;D
Since your PS doesn't work without it, it's too bad that more stuff must be broken. :'(

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