Broken Desktop. How to test PSU?

[DeusEx]

My desktop stopped working a while ago and i think its about time i fixed it.

Symptoms: Computer turns on and shuts off. Sometimes computer turns on and stays on, however the monitor says its not getting a signal and defaults to power saving mode.

I bought a new video card (one of the low end passively cooled 5xxx radeons ). I plugged it in but it made no difference. One thing that i may point out is that this card came with no cables. Does this mean it does not need to be connect to the psu for power ? Or did they just not include a cable?

Ram has been ruled out, so its either the CPU, motherboard or the PSU. Since the failure rates of CPUs are extremely low, i am thinking Motherboard or PSU.

My questions.

1. Whats the deal with the video card? Does it really not need any power? You just plug it into its slot in the motherboard and its ready to go ?its the HD5450 passively cooled. [i noticed 1 small connector on the card, but assumed its for a fan which is not on the card, so therefore useless for me. is this correct?]

2. How do i test the psu to make sure its not faulty? I can get voltmeter etc... can someone tell me of a detailed procedure how to test it?

3. How do i test the motherboard to make sure its not faulty?

[pwcmed]

What are the temps of the CPU in the bios?

Most 5670 and below are powered by the PCI Express slot. That connector is most likely for a fan. Have a model number?

Power supply testers are pretty cheap.
http://www.newegg.com/Product/ProductLi ... er&x=0&y=0

Because motherboards and CPU are hard to troubleshoot I would rule them out last. I've never had a motherboard or CPU go bad without help from my hands.

[Apoptosis]

Does the video card have a power connector on it? Got a link to the cards page on the companies site? I haven't seen a 5450 need extra power as the PCIe slot provides more than enough for the Radeon HD 5400 series. I got a couple of those cards here and they have no power headers on them nor do they need it. I don't think that will be the cause of your issue.

Do you have another PSU to swap yours out with to try?

If you have a volt meter you can check the 5V and 12V rails on one of the 4-pin molex connectors real quick and easy. The 3.3V needs to be checked on the 24-pin ATX PSU connector and is a bit tougher to find and get to. If you have a volt meter I can walk you through it though. I'd check the PSU first and then the board/cpu. The PSU is easier to check if you are wondering why I'd do that first... no other reason.

[DeusEx]

My video card is this: http://www.newegg.com/Product/Product.a ... 6814131339 . I also think that the connector is for the fan, but since the card is passively cooled they didnt include it. (b/c it actually has no fan).

-I cant check cpu temps in bios because bios doesnt start up. All i get is a black screen. i have disconnected and reconnected the monitor and the most i can get is a confirmation that the monitor findsthe dvi port. Cant see much besides that.

-I do not have another psu unfortunately. I can get a voltmeter... However i am a total psu newbie and do not even know what a molex is or the rails are. I can take the picture of the psu if needed and I could upload it here so it is obvious what we are discussing. A walkthrough is exactly what i need! so id appreciate the help.

[Major_A]

My endeavors with testing a PSU with a multimeter, might help. Turned out the two RAM kits I had installed weren't playing well with each other.
http://forums.legitreviews.com/about30319.html

[pwcmed]

Do you have the speaker hooked up to the motherboard. It could point you in the right direction with the error beeps, if it gets that far. I would buy a cheap tester and test it with that.

Google is not only my friend but he is yours as well.


With a tester

[DeusEx]

Thank you for the guidance so far. I will look into how to test the psu based on the information you guys provided and report back with the results in the next 1-2 days.

Still have to do all of that xmas shopping !

[DeusEx]

okay so i took a look at the 2 videos. I dont have a tester so only the first one was relevant. However i ran into a major problem... My connectors on the Fan as well as the PSU are completely different. The psu has black connectors, the fan has a solid white one. I took a pic of both. I do NOT have the clear connectors as shown in the video (for both the fan and the PSU).

I cant connect the fan to the psu. What the heck am i supposed to do now?

http://img707.imageshack.us/img707/328/ ... 143923.jpg
http://img222.imageshack.us/img222/241/ ... 144649.jpg

[Major_A]

You are supposed to jump the power supply at the 24 pin plug (the big one on the motherboard - green and black). Then you can take the multimeter and get readings using the molex connections.

[pwcmed]

Deus I would suggest you get a better understanding of a power supply before you put a multimeter on one.

http://en.wikipedia.org/wiki/Power_supp ... omputer%29

The easiest and safest bet would be to buy a tester.

If you go the multimeter route, I did a quick Google search and found a picture that will help you identify the type of connectors.



Here is my recommedation again

Power Supply Tester

http://www.amazon.com/Coolmax-Power-Sup ... 483&sr=8-1

[Major_A]

Might want to mention this too. Unplug the PSU from the wall before you start putting wires in the ATX plug to jump it.

[lordvic]

+1 for pwcmed; the black plug in your picture was a SATA connector. The 20+4pin is ALWAYS the big blocky one.

You gotta be careful when you do the "paper-clip" trick; you don't want all the amperage and volts from the wall to go through you. If not, your PC isn't the only one that's going to be dead, if you get my drift.

Ground yourself...and I'd recommend that you wrap electrical tape around where you would hold the paperclip.

Good Luck.

[DeusEx]

i know where to put a paperclip. The instructions you provided says that you need to have the psu plugged into a fan before you can go through testing it. which connector do i used to connect my fan to the psu given the one i have? (as is evident in the picture).

Or are you suggesting to just bridge the green + black wires and then test the voltages with a volt meter?

[Major_A]

If you buy a power supply tester, you get two things from it.
1) Did the power supply turn on?
2) If yes to 1, what are the reported voltages?

You can do both of these with a paper clip and a multimeter. I guess it said to hook up a fan to put a load on the PSU, but how much of a load would that be? I think hooking anything up would be a waste of time. The only load that might draw from the power supply would be a daisy chain of 20 Sunon Tornado fans running at 12V.

[DeusEx]

in that case i just need to find out this. After i bridge green + black and put the power on... Where exactly do i put the 2 rods from the volt-meter to test each wire's voltage? Ill wear gloves so no worries there, just not sure how to proceed.

Obviously 1 rod must go into the wire being tested. But what about the other one?

[pwcmed]

in that case i just need to find out this. After i bridge green + black and put the power on... Where exactly do i put the 2 rods from the volt-meter to test each wire's voltage? Ill wear gloves so no worries there, just not sure how to proceed.

Obviously 1 rod must go into the wire being tested. But what about the other one?

Deus I applaud you for trying to test your power supply but I recommended the tester because your earlier comments and now this last one. You should really try to educate yourself on power supplies before proceeding.

[Major_A]

Google came back with this, might help.
http://hardwarelogic.com/articles.php?id=5075

[DeusEx]

If i knew what i was doing i wouldnt be on the forums asking for help. Thanks for the article ill give it a glance. Im in no rush so i can take the time to learn whatever i need to learn, but i do not have money for a PSU tester.

PS: I may consider video taping my efforts so in case something goes horribly wrong we can all have a nice laugh about it later.

[DeusEx]

just to give an update... I did not have time to test the psu with a voltmeter (holidays, etc..). But my brother was buying a new pc. We swapped the PSUs.... (new one from newegg).. And - Nothing. Same deal.

So i remembered reading somewhere that the 3v round battery in the motherboard could cause problems if its dead. So i replaced it and believe it or not that was the culprit! after almost a month of not working my pc is running again thanks to that small insignificant battery.

Wow.

[Major_A]

Never had one of those go bad I guess. It's cool that got it fixed and I'll keep that in mind if I run across this in the future.