Solved

What is preventing my computer from switching on

Posted on 2008-06-25
4
389 Views
Last Modified: 2013-12-11
Hi, I have a computer, a Shuttle SN85G4 with a socket 754 Sempron Processor, 256mb Ram, an 80Gb SATA hard disk. When I go to switch on my computer the blue power light flashes, the fans spin for a fraction of a second and then it switches off, further depressions of the power button produce no affect whatsoever. If I pull the power lead out and plug it in again the same happens, but after a few attempts it will boot up though the number of attempts varies to produce a result. Once it has booted up it runs fine.
I suspected the power supply and swapped it out, I thought it seemed better for a day or so, but now it is the same so I have replaced the original power supply. I have tried swapping the ram to no effect. I have removed the motherboard and cleaned and reinstalled it. I notice the bios reports the sempron processor as an unidentified Clawhammer type processor. Could a CPU cause these types of problems? What else could cause this?
0
Comment
Question by:textusdominus
  • 2
4 Comments
 
LVL 31

Assisted Solution

by:Frosty555
Frosty555 earned 75 total points
Comment Utility
I've experienced this on two computers before. Eventually after testing everything I could I decided it was the MB that was the problem and replaced the machine.

It may or may not be the case for you, but I would suspect the motherboard. Incorrect detection of the cpu I think also points towards a motherboard error. Perhaps try resetting the bios on the motherboard (via pin jumpering, check the manual).
0
 

Author Comment

by:textusdominus
Comment Utility
I have never flashed the bios and the processor is newer than the board, so maybe a bios update would resolve that. Could a incorrectly detected CPU cause these kinds of issues? Doesnt the processor send some kind of power good signal to the Power supply?
0
 
LVL 69

Accepted Solution

by:
Callandor earned 175 total points
Comment Utility
I agree with Frosty555 - you have a power problem, typically caused by bad capacitors in the power supply or motherboard.  The key is the fact that you are able to power up after removing the plug and it keeps running once it starts.  You swapped the power supply, so that leaves the motherboard, and that's what you have to replace.  The motherboard obviously has other problems, such as recognizing your cpu, but you need to replace the motherboard.  See www.badcaps.net for examples of bad capacitors (bad caps aren't always visible on the outside, though).
0
 
LVL 31

Assisted Solution

by:Frosty555
Frosty555 earned 75 total points
Comment Utility
Updating the bios to the latest revision is probably a good idea. I'll find you the website. There is a windows based tool that does it for you.

The jumper thing is to reset the SETTINGS. It's not a reflashing at all, you just place a jumper on the motherboard in the right place and it resets all the cmos / bios settings back to factory defaults.

Here is the website with info on your MB - bios updates and the windows tool etc.:
http://eu.shuttle.com/archive/en/sn85g4_faq.htm

And the manual is here. Apparantly the MB is model # "FN85"
http://eu.shuttle.com/download/Archive/Manuals/en/fn85/fn85en.zip

On page 26 of the manual (based on the numbers at the bottom of the page), is instructions on resetting the cmos settings by using jumper JP11 on the motherboard. Follow those instructions. A summary of the instructions:

1. Turn off system
2. Remove ATX powre cable (remove power cable from motherboard)
3. Remove jumper cap from JP11 (pins 1-2)
4. Place jumper cap on JP11 (pins 2-3)
5. Wait a few seconds
6. Remove jumper cap and replace where you found it (JP11 pins 1-2)
7. Reattach ATX power cable and power on the system

But look at the manual I gave you. It has diagrams on where you can find this jumper.
0

Featured Post

6 Surprising Benefits of Threat Intelligence

All sorts of threat intelligence is available on the web. Intelligence you can learn from, and use to anticipate and prepare for future attacks.

Join & Write a Comment

Suggested Solutions

So, if your PC is old or new and it does not boot or has no display then what do you do? Precautions : -During connecting or disconnecting devices, be sure to have the AC electrical power disconnected -Temporarily ground yourself, or use a wris…
In the modern office, employees tend to move around the workplace a lot more freely. Conferences, collaborative groups, flexible seating and working from home require a new level of mobility. Technology has not only changed the behavior and the expe…
Access reports are powerful and flexible. Learn how to create a query and then a grouped report using the wizard. Modify the report design after the wizard is done to make it look better. There will be another video to explain how to put the final p…
This video explains how to create simple products associated to Magento configurable product and offers fast way of their generation with Store Manager for Magento tool.

763 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

10 Experts available now in Live!

Get 1:1 Help Now