Solved

Computer will not power on - Help needed

Posted on 2006-10-19
6
179 Views
Last Modified: 2010-04-26
I have a custom built system that has worked fine for about a year.  The other day the system will not power on.  When you press the power on button the leds flash for a second and all fans begin to turn but then nothing.  No changes had been made to the system hardware.  I pulled all the cards checking with each removal and still the same thing.  I also tried each of the two memory sticks individually and in different positions, same result again.  I pull and reseated the BIOS battery but have not chaecked it for voltage (need to bring a meter home from work).  The MB power light is on whenever power is applied.  I also disconneded the drives, DVD's, floppy, etc. with the same result.  I also pulled the CPU fan and reseated the CPU and fan again still the same problem.  I also disconnected the MB power caple and jumpered the Green to Black wires and the power supply started (again I do not have a meter to test the output).  Upon reconnecting the MB power cable I had the same problem.  All of this was last week and I did not have time to work on the system again until yesterday.  I turned the system on yesterday and it started?????  I restarted and started the system, powered off and retarted...  Everything was fine

Today I am back to where I was before and the system will not power up.  I started again as I did above and removed most of the cards.  When I disconnected the 4 pin CPU power cable on the MB and the power supply will start and the drives will run up when pressing the power switch.  Plug it back in and it will not start.

Any ideas as to where I should start?  Power supply, MB, CPU ????
0
Comment
Question by:jllabs
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
6 Comments
 
LVL 5

Accepted Solution

by:
Christophermagee earned 125 total points
ID: 17770866
Probably start with the power supply since that is the cheapest of the three, and a power supply is more likely to die than the cpu or motherboard.

Hope this helps.

0
 
LVL 7

Expert Comment

by:lukeca
ID: 17770970
I would inspect your motherboard closely, look at the capacitators (the cylinder shaped things all over your board).  Check for any that are bulging on the top or are leaking.  If any of them have issues then your motherboard is the problem.
0
 
LVL 7

Expert Comment

by:imacgouf
ID: 17771295
Hi,

An article from PCGuide with information on Power Supply, Function and Signal.
If your motherboard and components are being supplied poor-quality power, you will have problems that you wouldn't have if they received proper, high-quality power. If you plan on using your PC heavily, or if your data is important, or if you are looking for upgradeability in the future, you must pay attention to power! Power issues are responsible for more PC problems than probably any other single source, even though most people don't realize that the power is responsible. This chapter takes a look at power, both internal and external to the PC.
http://www.pcguide.com/ref/power/index.htm



0
Use Case: Protecting a Hybrid Cloud Infrastructure

Microsoft Azure is rapidly becoming the norm in dynamic IT environments. This document describes the challenges that organizations face when protecting data in a hybrid cloud IT environment and presents a use case to demonstrate how Acronis Backup protects all data.

 
LVL 2

Expert Comment

by:Freshcafe
ID: 17771928
There shouldn't be a four pin CU power cable or connector even in a cutom built PC. Do you means the Hard Disk drive? Ther are standard Power connecttions for the Main Board and none of it directly connect to the CPU. (wake on LAN etc but not CPU). Two possibilties I can think of without seeing it or have all the info - PSU and HDD.

PSU not supplying correct power under load even if it reads correct voltage; when tested they usually are disconnected from the at least 1 system connection.

And the other is the HDD pulling down the system , drawing too much current.

In either case the above answer from imacgouf would be correct because either the 5Volt, 12Volt or power supplied is probably up to the standard.
0
 
LVL 92

Expert Comment

by:nobus
ID: 17772117
i would replace the bios battery; if you can measure it, it should read 3 V
0
 

Author Comment

by:jllabs
ID: 17858147
Replace the power supply three days ago and no problems so far.  Thanks everyone for your help!
0

Featured Post

On Demand Webinar - Networking for the Cloud Era

This webinar discusses:
-Common barriers companies experience when moving to the cloud
-How SD-WAN changes the way we look at networks
-Best practices customers should employ moving forward with cloud migration
-What happens behind the scenes of SteelConnect’s one-click button

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

I use more than 1 computer in my office for various reasons. Multiple keyboards and mice take up more than just extra space, they make working a little more complicated. Using one mouse and keyboard for all of my computers makes life easier. This co…
Finding and deleting duplicate (picture) files can be a time consuming task. My wife and I, our three kids and their families all share one dilemma: Managing our pictures. Between desktops, laptops, phones, tablets, and cameras; over the last decade…

739 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