I recieve no power when I turn the PC on?

[davepegg10]

Hi,

I bought this PC from microdirect.co.uk,

http://www.microdirect.co.uk/produc...?ProductID=7640,

Once I recieved it, I started it up and installed XP and everything worked fine. I then turned it off and didn't use it for about a month as I had no available monitor.

I went to turn it on yesterday for the first time since, only to find it wouldn't turn on. Not even a blip. I was using all the leads from my old PC, which still works perfectly, so I don't understand why the new one doesn't.

I opened it up and the inside LED light on the motherboard is still on whilst the power is on, it's just that it won't start up.

What could the reason for this be? ANy ideas?

I appreciate the help.

[halovivek]

please check whether your SMPS (power supply ) inside the CPU

[davepegg10]

Please explain a bit further, what exactly should I be checking for?

[FastLearner]

If I was able to use Sylvander's flowcharts correctly (not sure), your power supply fan is faulty.

Check again to make sure everything is fully seated and when possible, try a known good power supply and see if it makes a difference.

Why not just change the PSU fan?--because the PSU is a field replaceable unit that a person who doesn't know exactly what they are doing (such as myself) is better off replacing without having to open up the PSU (where there is enough voltage to put us on our backs). Monitors fall into the same category.

[Sylvander]

Download a copy of my diagnostic flowcharts from here
www.erniek.eclipse.co.uk/downloads/sylvanderdiags.zip
and print them to leaf through.

Begin on the START UP chart.
1. Is the PC dead? No.
[An LED on the motherboard is lit (are there any other signs of life?)]
2. Did the POST appear to run? I'll assume not.
3. Did you hear a single short beep indicating successful POST? No.
4. Did you hear any other beep patterns indicating errors? No.
I'll assume the internal speaker works and that POST did not complete.

NO POST
5. Either use a known good PSU or assume for the moment that the existing PSU is ok.
6. Disconnect all peripherals and system adapter cards, but leave the keyboard and video/monitor connected. [At least 1 stick of RAM, CPU & CPU fan should remain connected].
7. If the POST still doesn't complete, then the system board or something that remains connected to it [including the BIOS settings] is faulty.

"I started it up and installed XP and everything worked fine. I then turned it off and didn't use it for about a month"
I believe that if WinXP is not registered with Microsoft within 30 days, then WinXP disables itself! :(
I wouldn't think that Windows could prevent the POST from completing though.

[FastLearner]

Sylvander, how is it that we both used your flowcharts but came up with a different analysis?

I came to the conclusion of the faulty PSU fan by following your flowcharts in the following way, so please correct me where I made a mistake:

1) Is the PC dead? - yes, nothing happens when he turns it on. To me, that's dead, but that appears to have been my first mistake.

2) DF2: System

3) Does fan run? - no

4) are power supply voltages correct? - yes. I assumed they were since his mobo led is showing. Probably my second mistake.

5) Answering the questions in that order, the diagnosis of the flowcharts is Fan in Power Supply Unit faulty.

Although your flowcharts are very good and thorough, they are a little bit difficult for hardware beginners such as myself to use. I guess it may be do to the general undefined terms like "dead". To me, if nothing happens when I push the power button, my baby is dead.

davepegg10: please disregard my post. I thought I was headed in the right direction, but it appears as though I have incorrectly used the flowcharts. Sorry...:(

[Sylvander]

"how is it that we both used your flowcharts but came up with a different analysis?"
Ah, it depends on which "route" you take through them, which depends on the "turning" you take at each "crossroads".

e.g.
"1) Is the PC dead? - yes, nothing happens when he turns it on. To me, that's dead, but that appears to have been my first mistake."
My decision was that the LED indicated that the PC was NOT totally dead. [Am I wrong?]
Any sign of life, no matter how small, indicates the PC isn't dead.
There must be power getting through. Can anyone confirm that?
Perhaps there were other signs not mentioned?
That's where we took different routes.
I assume that the PSU fan will be running if the PSU is working [unless the fan is faulty].


"Answering the questions in that order, the diagnosis of the flowcharts is Fan in Power Supply Unit faulty."
The PSU fan running or not is usually used to indicate whether the PSU is supplying power or not. Sometimes the fan itself could be faulty, so in this case its failure to spin should be disregarded as an indicator.

"To me, if nothing happens when I push the power button, my baby is dead."
Quite so, but it must be totally dead, no signs of life whatever.
What you're trying to decide is whether power is being supplied and getting through.
If it wasn't plugged in at the wall, how could there be signs of life?
Perhaps because capacitors were providing a small supply?
Could they power the LED?

[FastLearner]

Thanks sylvander. Now if I look at "dead" being no life at all, I come to the exact point in the flowcharts as you did. Cool...:D

So if POST runs, the next step will be to reconnect the floppy drive and run advanced diagnostics. If it does not, mainboard is shot (assuming his PSU is functioning because of the LED "life"). Is this correct?

I'm not convinced, though, that just because an LED is on, that means that the voltages of the PSU are correct. How could he verify this?

I downloaded your flowcharts a while ago and they are really excellent, Sylvander.

[Sylvander]

"How could he verify this?"
------------------------------------------------------------------------------------------------------------
TESTING ATX POWER VOLTAGES

See this http://www.pcguide.com/vb/showthread.php?s=&postid=152496#post152496

Black = ground
Red = +5 volts
White = -5 volts
Yellow = +12 volts
Blue = -12 volts
Orange = +3.3 volts (?)
Green = power on

Turn the power on. The fans should at least come on so that you know you have power.

Turn on the voltmeter and set it to measure DC voltage. Start with an IDE power connector that is not used. Place the black lead of the voltmeter in the hole of the connector that has a black wire (ground). Connect the red lead of the voltmeter first to the yellow hole and then to the red hole. The voltmeter should read +12v and +5v respectively.

The other voltages may usually be measured at the motherboard power connector by simply sliding the red multimeter test probe down the hole where each colour wire goes (with the black probe connected to any black wire as before). Really you only need to check the orange wire for 3.3 volts at this connector. If +12, +5, and +3.3 volts are all okay, then your power supply is probably fine.

Unfortunately, a low voltage measured in this way may mean a bad PSU or that some other component (motherboard, etc.) has a short and is pulling the voltage down. Therefore, the main value of measuring voltages is to eliminate the PSU as a source of the problem (if it has normal voltages).
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"Now if I look at "dead" being no life at all, I come to the exact point in the flowcharts as you did."
This is a learning process for me too.
I'd like to hear from someone who knows, whether the LED is getting power from the main supply, or whether this is simply a small source of stored energy held in a capacitor. In the absence of sure knowledge I assume it's coming from the main supply and therefore the PC isn't "dead".

"So if POST runs, the next step will be to reconnect the floppy drive and run advanced diagnostics."
I believe most people don't have a diagnostics prog. My PC came supplied with a diagnostics floppy that does comprehensive tests.
You can get Tuff-Test Lite = http://www.tufftest.com/free.htm for free.
If you boot with this in the FDD, it runs automatically and you just sit back and watch as it tests.

"If it does not, mainboard is shot (assuming his PSU is functioning because of the LED "life"). Is this correct?"
I wouldn't go so far as to say the "mainboard is shot".
Just that either the motherboard [or something "on" it] isn't functioning.
It could be something as simple to fix as an incorrect BIOS configuration setting.

[FastLearner]

very good info. Thanks Sylvander! I've printed it out for future reference. I really like the way you talked through the testing using a voltmeter. I have purchased a cheap, battery operated, digital multimeter for under $10, and now I feel much more confident in knowing how to use it.

[Sylvander]

I'm only passing on info supplied by "gwallen4".

I don't even have a multimeter. :(

So perhaps you can teach us something. :)

Every little helps, so long as the movement is ahead eh?

Here's one I came across today
Testing PSU Voltages
http://www.ochardware.com/articles/psuvolt/psuvolt2.html

[CoachB22]

I would suggest checking the case power switch connection to the motherboard. I assume this PC was mailed to you and perhaps you moved it a couple of times while it was not in use?? LED on indicates mobo is getting power from PSU.

CoachB