# [SOLVED] No post, no beep, no fans



## kunit1 (Jul 25, 2008)

Hi all,

I have been stuck with this problem for two days now and come here in hope of some help. I have a PC which I built some time ago, and suddenly it stopped working. When pressing the power button absolutely nothing happens, no post, no beeps, and non of the fans spin. 

The first thing I test was the PSU. I took out the 24 pin plug, shorted the green wire and the PSU fan started spinning. I tested some of the pins and they showed the expected voltages (12V showed 11.95V etc...). 

At this point I started thinking that the Motherboard (Asus P5B Deluxe) was the problem. So I went and bought a new motherboard(BioStar G41-M7) and new set of RAM sticks. I replaced the motherboard and the RAM but the same problem remains. When pressing the power button absolutely nothing happens.

I am really stuck here. I even tried a different graphics card but the same issue. I also tested the power button for continuity and it was fine

My questions are:

-Can a bad CPU cause the computer to do absolutely nothing (no fans, no beep)?

-Is it still possible that the PSU is bad even though it provides the correct voltages?

I would really appreciate your help as I am really stuck here.

Thanks,


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## [email protected] (Nov 16, 2004)

*Re: No post, no beep, no fans*

From your described symptoms, it is still possible that the PSU could be the problem, but also, a short somewhere could _make_ the PSU behave this way.

Over time, vibration can even short out a wire to the front panel if it's over a sharp edge or crushed by a case component.

Your eyes are the best tools to use. Inspect all wiring.

Take out the mobo, and lay it on the cardboard box it came in. If it has an internal video system, use it. Remove the PSU, and plug it into the mobo. Also the kybd and your monitor. Nothing else. Turn on. Momentarily short the two pwr pins on your mobo with a flat blade screwdriver. (You might need to look up your mobo or check the book - don't just unplug the front panel without having a guide).

What happens?


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## Dblanchard1278 (Jun 18, 2009)

*Re: No post, no beep, no fans*

Can you psot the specs of your pc? (Brand and model)
CPU
Motherboard
Ram
Video Card
Hard drive
cd/dvd drive
PSU (Brand, Model, and wattage)

A bad psu can cause all sorts of problems if they don't provide stable power to the system. I would start by getting another quality psu and start from there, most likely you pushed the old one and it over volted the board and or other componets causing damage. But it's hard to say with out knowing what you have and as of right now it could be a few things and it will take some work with parts swapping to diagnose the problem.

Two things you can do is 1. Reset the bios. Unplug the power cord from the tower or pc.
Remove the side pannel and look for a jumper call clr_cmos and move the jumper over one pin to clear the cmos. (example, if pins 2 and 3 are covered then move the jumper over pins 1 and 2 for 5 minutes) Or remove the large coin sized battery from the board for ten min and reinsert it.
Then plug in the power cord and satrt the pc.
Another thing you can try is removing all the ram sticks and see if you get a series of beeps.


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## kunit1 (Jul 25, 2008)

*Re: No post, no beep, no fans*

thanks for the replies

let me start with the specs

*CPU:* Core 2 Duo 2.13GHz
*Motherboards:* Asus P5B Deluxe(originally in the system) and BioStar G41-M7(New, just bought)
*Memory:* 4x1GB Kingston ValueRAM (originally in the system) and 2x2GB Mushkin (New, just bought)

*Video card:* ATi 4870 1GB

*PSU:* SilverStone 500W
Hooked up PSU, CPU, one memory stick, used internal Vid card and then shorted the power switch pins with a screwdriver. Nothing happens, not even a single thing.

Tried the samething without memory sticks installed, and again on both motherboards I get no response or any sign of life.

Another thing I tried was to take out the CPU and try starting up without it and again I get nothing.

I also tried resetting the CMOS on both motherboards; I even checked the voltages on the CMOS battery and it was 2.92V which should be fine.


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## [email protected] (Nov 16, 2004)

*Re: No post, no beep, no fans*

Well, looks like the CPU has an internal short that shuts down the PSU the instant you try to power up. That would explain why there is no POST beep or any of the fans starting up. You've changed everything else and tested with minimal devices connected. Kind of points to the CPU.

I'd pull it out and visually inspect all the CPU's pins. Make sure none of them are bent or broken off.


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## Dblanchard1278 (Jun 18, 2009)

*Re: No post, no beep, no fans*

First of all 500 watts is not enough for that system and that could be the problem, I douybt the cpu is the problem due to the fact that you pretty much replaced everything and no improvement. The only thing thats sticks out is that low quality psu. But the only way to tell is by putting the cpu in a system You know that works and can handle it. 

For your system you should be running 650 watts with a quality psu like this http://www.newegg.com/Product/Product.aspx?Item=N82E16817139005

I would try getting a quality 650 watt psu like the one I posted or one from seasonic to power that video card.


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## [email protected] (Nov 16, 2004)

*Re: No post, no beep, no fans*

I got called away suddenly and didn't finish my thoughts. And Dblanchard1278 is right of course, try a substitute 650W PSU before you make any decisions.


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## kunit1 (Jul 25, 2008)

*Re: No post, no beep, no fans*

I understand what you guys are says, but I have been using this same PSU on this same system for over a year now and it had no problems. But just to eliminate all possibilities from least expinsive to most, I am going to buy a new 650 W PSU tomorrow and then report back. I am trying to leave replacing the CPU as a last resort cause it's the most expensive out of the rest.


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## dai (Jul 2, 2004)

*Re: No post, no beep, no fans*

i would prefer to see a 750w being used with that card


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## kunit1 (Jul 25, 2008)

*Re: No post, no beep, no fans*

I am back,

Let me start off by expressing my thanks to all of you. 

I was able to get the computer up and running with no problems.

For the benefit of other users:

The motherboard was find, CPU was fine, and RAM was fine. The problem was the PSU. Even though there was voltage on the terminals that doesn't mean that the PSU is working properly. P=IV hence, the only way to be sure is to check the current flow under load which is tough with a PC PSU.

Long story short, the PSU was not outputting the correct amount of power. As a result, the motherboard was being underpowered and that's why it was not starting up. I bought a new PSU today and computer started right away.



Thanks,


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## dai (Jul 2, 2004)

*Re: No post, no beep, no fans*

glad you have it sorted


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