Jump to content

Welcome to Geeks to Go - Register now for FREE

Geeks To Go is a helpful hub, where thousands of volunteer geeks quickly serve friendly answers and support. Check out the forums and get free advice from the experts. Register now to gain access to all of our features, it's FREE and only takes one minute. Once registered and logged in, you will be able to create topics, post replies to existing threads, give reputation to your fellow members, get your own private messenger, post status updates, manage your profile and so much more.

Create Account How it Works
Photo

Computer doesn't come on, no power?


  • Please log in to reply

#1
civiccrazy

civiccrazy

    Member

  • Member
  • PipPipPip
  • 244 posts
The other day I was trying to work on a light in my house and I was flipping breakers off to find which one the light was. In that process I flipped off the breaker for the outlet for my computer. Now ever since I did that my computer won't turn on. I checked the power supply, it is fine. So i thought it was the motherboard. so i just replaced it last night. The computer still doesn't work. Would anyone please be able to help? or have any suggestions?
  • 0

Advertisements


#2
rshaffer61

rshaffer61

    Moderator

  • Moderator
  • 34,114 posts
Have you tried anything else in that outlet to make sure it is actually turned on?
Does the fan on the cpu stay on when the power is turned on?
  • 0

#3
civiccrazy

civiccrazy

    Member

  • Topic Starter
  • Member
  • PipPipPip
  • 244 posts
I have tried to plug it in into another outlet. So I dont think its the outlet. The cpu fan never comes on.
  • 0

#4
rshaffer61

rshaffer61

    Moderator

  • Moderator
  • 34,114 posts
Have you tried a bench test to check just the mobo outside of the case?
If not do the following.

Disconnect everything from the Motherboard except
  • keyboard
  • mouse
  • video output
  • 20+4 powercable
  • 4/8 pin 12v wire both coming from the powersupply,
  • Cpu fan wire
  • power and reset button to the case
  • case speaker
Now you should have NOTHING connected to the motherboard except what was listed above.

The goal here is just to test the mobo:

If the computer still will not boot up the please remove the motherboard from the computer along with the power supply

place the motherboard on a piece of card board larger than the motherboard,

this will eliminate a short from the mobo to the case which could be a possibility
Install the cpu with, 1 stick ram in dimm 1, power supply, case switch and case speaker
Connect ps2 mouse and keyboard along with the monitor
Repeat the above and power on
If the computer now boots into bios you most likely had a case short so make sure when installing the motherboard in the case that you use standoffs and they line up with the mounting holes in the motherboard and none of the standoffs touch anything else on the underside of the board.
  • 0

#5
Digerati

Digerati

    Grumpy Ol' MSgt (Ret.)

  • Retired Staff
  • 3,997 posts
  • MVP
How did you check the power supply? Here's my canned text on testing PSUs:

To properly and conclusively test a power supply unit (PSU), it must be tested under various realistic "loads" then analyzed for excessive [url="http://en.wikipedia.org/wiki/Ripple_(electrical)""]ripple[/url] and other anomalies. This is done by a qualified technician using an oscilloscope or power analyzer - sophisticated (and expensive) electronic test equipment requiring special training to operate, and a basic knowledge of electronics theory to understand the results. Therefore, conclusively testing a power supply is done in properly equipped electronic repair facilities.

Fortunately, there are other options that are almost as good. I keep a FrozenCPU Ultimate PSU Tester in my tool bag when I am "in the field" and don't have a good spare power supply to swap in. While not a certain test, they are better than nothing. The advantage of this model is that it has an LCD readout of the voltage. With an actual voltage readout, you have a better chance of detecting a "failing" PSU, or one barely within specified ATX Form Factor Standard tolerances. Lesser models use LEDs to indicate the voltage is just within some "range". These are less informative, considerably cheaper, but still useful for detecting PSUs that have already "failed". Newegg has several testers to choose from. All these testers contain a "dummy load" to fool the PSU into thinking it is connected to a motherboard, and therefore allows the PSU to power on, if able, without being attached to a motherboard - great for testing fans, but again, it is not a true load or suitable for conclusive testing.

As mentioned, swapping in a known good supply is a tried and trued method of troubleshooting used for centuries, even by pros. Remove the "suspect" part and replace with a "known good" part and see if the problem goes away.

I do not recommend using a multimeter to test power supplies. To do it properly, that is, under a realistic load, the voltages on all the pins must be measured while the PSU is attached to the motherboard and the computer powered on. This requires poking (with some considerable force) two hard and sharp, highly conductive meter probes into the main power connector, deep in the heart of the computer. One tiny slip can destroy the motherboard, and everything plugged into it. It is not worth the risk considering most multimeters, like plug-in testers, do not measure, or reveal any unwanted and potentially disruptive AC components to the DC voltages.

And remember, anything that plugs into the wall can kill. Do not open the power supply's case unless you are a qualified electronics technician. There are NO user serviceable parts inside a power supply.
  • 0

#6
civiccrazy

civiccrazy

    Member

  • Topic Starter
  • Member
  • PipPipPip
  • 244 posts
ok I hooked everything up like rshaffer61 said pushed the power button and the computer seemed to start up...beeped 9 times and shut back off.

The only video output I have is for my viedo card. So, that wasn't hooked up
  • 0

#7
rshaffer61

rshaffer61

    Moderator

  • Moderator
  • 34,114 posts
Check the memory and make sure it is seated correctly.
  • 0

#8
civiccrazy

civiccrazy

    Member

  • Topic Starter
  • Member
  • PipPipPip
  • 244 posts
I just hooked everything up and just put 1 memory stick in and it started up fine. I will do some more testing with the other memory stick. Maybe it was bad. Would that cause the computer to not start up at all?
  • 0

#9
rshaffer61

rshaffer61

    Moderator

  • Moderator
  • 34,114 posts
Yes if system won't start the bad memory could cause it. The problem is you were not or did not say anything about any beeps till now.
Can you try the other stick of memory and see if it starts with that stick. If so then seat both sticks again and try it. another option is does your MOBO have color coded memory slots?
Did you check to make sure which banks are which as some MOBO's don't actually have banks next to each other or have to have certain banks used in order for system to boot correctly.
  • 0

#10
civiccrazy

civiccrazy

    Member

  • Topic Starter
  • Member
  • PipPipPip
  • 244 posts
I just now heard the beeps for the first time. Before that the computer wouldn't do anything. I tried the other stick off memory and now it didn't do anything.
  • 0

Advertisements


#11
rshaffer61

rshaffer61

    Moderator

  • Moderator
  • 34,114 posts
Same slot as the other memory stick?
If so then it seems you may have a bad memory module.
If this is correct then we need to get the system back together and then run memory test on the working module to make sure it has no underlining issues.
Let me know when you are ready for the next steps. :) :)
BTW good work on finding the problem.
  • 0

#12
civiccrazy

civiccrazy

    Member

  • Topic Starter
  • Member
  • PipPipPip
  • 244 posts
Now something different with it. I unhooked the connector for the front usb ports. THe system started up with both memory modules. So I think there has to be something wrong with that. another thing.....none of my usb ports are working in the back either.

Go ahead and direct me on how to do a memory test too. I will be back in a couple of hours. Everything seems to be fine now, with both memory sticks. But none of the usb ports work.
  • 0

#13
rshaffer61

rshaffer61

    Moderator

  • Moderator
  • 34,114 posts
OK let's check the memory and I have some ideals on the USB but we will do that after the memory test. Please leave all usb connections disconnected for the test.

The first part of this please skip as we have already tested ram sticks apart from each other.



If you have more than one RAM module installed, try starting computer with one RAM stick at a time.

NOTE Keep in mind, the manual check listed above is always superior to the software check, listed below. DO NOT proceed with memtest, if you can go with option A

B. If you have only one RAM stick installed...
...run memtest...

1. Download - Pre-Compiled Bootable ISO (.zip)
2. Unzip downloaded memtest86+-2.11.iso.zip file.
3. Inside, you'll find memtest86+-2.11.iso file.
4. Download, and install ImgBurn: http://www.imgburn.com/
5. Insert blank CD into your CD drive.
6. Open ImgBurn, and click on Write image file to disc
7. Click on Browse for a file... icon:

Posted Image

8. Locate memtest86+-2.11.iso file, and click Open button.
9. Click on ImgBurn green arrow to start burning bootable memtest86 CD:

Posted Image

10. Once the CD is created, boot from it, and memtest will automatically start to run.

The running program will look something like this depending on the size and number of ram modules installed:


Posted Image

It's recommended to run 5-6 passes. Each pass contains very same 8 tests.

This will show the progress of the test. It can take a while. Be patient, or leave it running overnight.

Posted Image

The following image is the test results area:

Posted Image

The most important item here is the “errors” line. If you see ANY errors, even one, most likely, you have bad RAM.
  • 0

#14
civiccrazy

civiccrazy

    Member

  • Topic Starter
  • Member
  • PipPipPip
  • 244 posts
Ran 6 passes. No errors! Usb ports work. I just had to wait for them to install. Since it is a brand new motherboard.
  • 0

#15
rshaffer61

rshaffer61

    Moderator

  • Moderator
  • 34,114 posts
USB ports work now?
Is the system booting up with the front USb ports connected now?
  • 0






Similar Topics

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users

As Featured On:

Microsoft Yahoo BBC MSN PC Magazine Washington Post HP