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Paper clip 1, PSU 0?

Last response: in Components
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December 7, 2011 12:17:00 AM

Hi :heink: 

Would appreciate advice on how to proceed with troubleshooting a power problem after my PC nosedived today and refuses to start again that I suspect but am not sure may be due to PSU failure - even though the famous "paper clip test" shows the PSU fan is working ok. Is this possible?

Here is the score so far:
*The computer is a self build with a new i7 Intel mobo and an older 520W Ace ATX PSU.
* I have used the computer in its current configuration for several months with no problems.
* After I used the computer for about an hour this morning the cursor suddenly FROZE, there was a NOISE from inside the computer case like an engine moving up into a higher gear (maybe a fan?), this noise continued for about 30 seconds then the screen went DEAD and the computer crashed
* when I tried to restart the computer fans revved for about 1 second but it did not start
* unplugged the power cord, opened the case, plugged the cord back in again, turned on the power switch, as soon as I did this a GREEN LIGHT on the motherboard beside the PSU connector came on and stayed on until I turned off the power switch.
* repeated the above a few hours later. same as above
* removed PSU and tried PAPER CLIP TEST. Turn on power switch and PSU fan spins normally until power off. Green light on mobo same as before. HD does not spin.
* check HD on another computer with SATA-USB connector and separate power lead direct to HD. No problem. HD works fine and all data intact. Phew!!!
* Reconnect PSU to mobo and HD. Turn on power switch. Notice ALL FANS including CPU fan spin for about 1 second then all stops. Green light on mobo same as before. HD does not spin. My brain spins :-(

QUESTION: Is it likely that I have a FAILED PSU??? even though the paper clip test shows the PSU fan is working and the green light on the mobo beside the PSU connector is also working?

Or does the above point to some other problem such as for example (yikes) mobo failure?



More about : paper clip psu

a b ) Power supply
December 7, 2011 12:23:51 AM

The true test will come when you swap in a PSU that you know is running properly. In all probability the PSU is the problem. If the rig does not run with a different PSU (make sure it is adequate for the rig) then swap out the mobo.
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December 7, 2011 12:46:05 AM

Thanks Chester, looks like I need to find another PSU even though am not sure if I can get hold of one without having to buy a new one, which is why I am trying to eliminate other possible problems first.

After posting this thread I just removed the video card, SCSI card, RAM and disconnected DVD player. Strangely enough all the fans run for a little longer when I turn on the computer now - about 3 seconds instead of 1 before they all cut off. If I hear right even the HD does a little tentative spin. Then everything goes dead same as before. When I turn the computer off and on same thing happens again. Is it not likely that this change in behavior suggests the problem is NOT PSU??

Obvious solution is to go visit a good computer repair technician asap but that is not easy for me to do as am posted abroad. So any advice much appreciated.
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a c 272 ) Power supply
December 7, 2011 1:18:27 AM

Do you have a case fan that runs directly from the PSU? If so hook that up to the PSU when you do the paper clip test, if it doesn't spin or seems to spin slower than normal that indicates a problem with the +12 V rail which your CPU and most other major components run off of.

The paper clip test is a basic functionality check and unfortunately doesn't tell you anything about the voltages coming out, or its load capabilities, if it fails the paper clip test you know its dead, if it passes it doesn't actually tell you anything about its state.

Also, the green light on the motherboard is powered by the +5 VSB rail in the PSU which is a simple linear transformer often which is really hard to kill off, if that didn't come on it would indicate that your PSU was totally cooked, but its presence does not tell you about the main power in the system as the source for the +5 VSB rail is totally isolated from the other main rails they could all be blown to bits and your board could still get stand by power so all we know right now is that your PSU isn't entirely dead, but it still may be only marginally functional.
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December 7, 2011 2:55:52 AM

thanks :) 

as Hunter suggests I hooked up the case fan & this is what happened:
1) switch on, same as before (all fans including case fan) spin for about 1 second then all shut down
2) switch off, wait, switch on again: all fans including case FANS RUN and keep running for several minutes :o  , switch off
3) switch on, nothing happens
4) switch off, wait, switch on again: all fans including case fan run and keep running, HD SPINS for about 10 minutes and appears able to continue indefinitely:o  , switch off
5) switch on, same as before (all fans including case fan) spin for about 1 second then all shut down :( 

Would not ERRATIC be the right word to describe what is happening?

So I am wondering if this could be because problems with the +12V rail or other components of the PSU arise not abruptly but bit by bit or is the +12V rail an either working/not working component?
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a b ) Power supply
December 7, 2011 4:28:26 AM

I hoped for a funny story where the paper clip fell into the PSU and made havoc inside, but I guess this is a problem worth commenting on as well... :p 

Anyhow, if the PSU itself shuts down with just a fan connected, it's in all probability fried. Regulators, caps, transistors, resistors, coils, resistors, etc. don't all just simply fail from 100% working to 0% working all the time. Usually a PSU is able to deliver just enough power to keep the PC running and working until one day it receives just that little nudge in a game or application that pulls just that little too much power, the failure on the PSU increases dramatically and it stops producing enough power to power the PC, with symptoms as the ones you're describing.

If you don't have a "spare" PSU lying around there somewhere, you can take the PC to a local PC shop, tell them you are 99% sure it's the PSU that has gone and ask them to just test your theory with another (test) PSU to confirm. They should do this for free, if they are any kind of decent human beings.

Oh, and the right word to describe this issue would be AGE. PSU's doesn't have long lives, they're one of the parts on a PC most likely to go and there's pretty much nothing you can do about it. Also, generic parts doesn't really help.
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December 7, 2011 7:20:05 AM

Oh, and the right word to describe this issue would be AGE. PSU's doesn't have long lives, they're one of the parts on a PC most likely to go and there's pretty much nothing you can do about it. Also, generic parts doesn't really help...

in other words PSU's are just like human beings!

one thing about leaving a problem stand and stew in its own juice for a couple of hours is that everything seems clearer in the morning: time to get a new PSU. Fortunatley my wife is home visiting family so I can order a new one and have her bring it back in her luggage. Meanwhile making do with my old laptop.

So now already know in advance what Santa will bring this year.

Thanks to all for the great advice :) 
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a c 144 ) Power supply
December 7, 2011 7:37:59 AM

Toxxyc said:

PSU's doesn't have long lives, ...

Not entirely true. I have a nine year old 400 watt Antec that still runs fine.

The following is extracted from my troubleshooting hints.
=====================================================================================================
You can use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire (standby power supply): 5 volts always on. The green wire should also have 5 volts on it. It should go to 0 volts when you press the case power button, then back to 5 volts when you release the case power switch. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=yout...

A way that might be easier is to use the main power plug. Working from the back of the plug where the wires come out, use a bare paperclip to short between the green wire and one of the neighboring black wires. That will do the same thing with an installed PSU. It is also an easy way to bypass a questionable case power switch.

This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.
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a c 243 ) Power supply
December 7, 2011 7:44:55 AM

jsc said:

You can use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire (standby power supply): 5 volts always on. The green wire should also have 5 volts on it. It should go to 0 volts when you press the case power button, then back to 5 volts when you release the case power switch. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=yout...

I know you're busy with the new responsibilities, but how long would it take you to turn that into a little guide to add to the sticky ? ;) 
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a b ) Power supply
December 7, 2011 7:51:04 AM

jsc said:
Not entirely true. I have a nine year old 400 watt Antec that still runs fine.

Exception to the rule. Also, it's an Antec... :D 
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December 23, 2011 9:32:29 AM

Today not only my wife landed but she also brought in her suitcase a new Corsair GS700 PSU for my Intel DP55WB :wahoo: 

PSU looks very fine BUT have just noticed it is "2x PCI-e - 6 pin and 8 pin compatable" (as shown here) whereas the motherboard only has a 2x2 processor core power connector (as the product guide shows on page 49 here)


So am I fried??? or do I need an adapter??? or...
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a c 243 ) Power supply
December 23, 2011 9:50:19 AM

lowep said:
Today not only my wife landed but she also brought in her suitcase a new Corsair GS700 PSU for my Intel DP55WB :wahoo: 

PSU looks very fine BUT have just noticed it is "2x PCI-e - 6 pin and 8 pin compatable" (as shown here) whereas the motherboard only has a 2x2 processor core power connector (as the product guide shows on page 49 here)


So am I fried??? or do I need an adapter??? or...

No, the psu has a 4+4 connector that splits to give you two 2x2's for cpu power
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December 23, 2011 9:59:20 AM

DELLUSER you should change your user name to FATHER CHRISTMAS!

Maybe I should change my username to USEYOUREYES :ange: 

So all I need to do is split the 4+4 into 2 2x2's and use either of the 2x2s, right?

Thanks and MERRY XMAS!!

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a c 243 ) Power supply
December 23, 2011 10:04:36 AM

Yes

Merry Xmas to you as well
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December 23, 2011 11:57:00 AM

Good news is the new GS700 PSU seems to work fine.

But bad news is that the computer does not work any better than before I replaced the PSU

Oh well :ouch:  maybe it is the mobo that is kaput?

When I connect the PSU to the computer and turn on the power switch the green light on the mobo lights up; the whole system starts up for about 1 second then goes dead no fans nothing. I remove the power cable from the PSU, replace it and switch on the system again and this time apart from that little green eye on the mobo nothing happens....

Just in case it was the power cable or the UPS I tried the paper clip test on the new PSU that worked perfectly also driving the case fan that I plugged in.... but when I removed the paper clip, connected all the computer cables and tried again nada - not even the case fan...
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December 23, 2011 2:02:29 PM

Hmm... looking to track down this turkey found this comment on another forum:

Make sure your computer is turning on, if you press the power button and nothing happens (no lights, no sound, no fans, etc.) then this issue is not a NO POST but is an power related issue.

As my computer is sometimes turning on just for a second or two but mostly not turning on at all with no beeps and no fan movement either my conclusion for now is:

(1) what I am facing is not a POST but a power related issue.

As I have just tested the system with a new PSU

(2) I can rule out the PSU as being the cause of the problem

So this suggests that the problem is either

(3) incorrect connection of the PSU to the motherboard - even though am sure the 24-pin connector and 4-pin connector are setup right and besides this the computer ran for months before it suddenly stalled then nosedived one day without any mucking around with the innards of the computer

(4) some other part of the system such as RAM etc but this is unlikely as even with everything removed from the motherboard and only the psu plugged in nothing happens, same with only one stick of ram installed instead of two, and if I swap the 2 sticks of ram with each other

(5) so maybe some part of the motherboard to do with power supply is damaged - eg capacitators. Is there any way to check this?
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December 28, 2011 7:32:31 AM

As the problem with my computer now seems more likely to be with the motherboard than the PSU I have started a new thread here in the motherboard section of the forum.

Thanks to everybody who helped me get this far in the troubleshooting :hello: 
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January 12, 2012 2:33:17 PM

Thanks Bevanjenn, did you read this:

But bad news is that the computer does not work any better than before I replaced the PSU

Oh well :ouch:  maybe it is the mobo that is kaput?
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