Short overview of how to troubleshoot bad hardware when a pc does not post

AID: 1945
  • Status: Published

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  • TypeBest Practices
  • Posted on2009-11-11 at 23:41:37
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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 wrist strap to prevent electric static discharges from destroying certain components.

Here are my troubleshooting procedures:

-With a new motherboard: verify if all mounting standoffs' holes correspond with the holes in the motherboard!!
   Or test the motherboard outside the case, on a wooden  (non conductive) surface
-Clean the system from dust, then  test with the minimum setup
 - Disconnect all peripherals devices (including the drives, CD, DVD, printers and keyboard) and network cables, except for the motherboard + CPU + 1 ram stick, video card, monitor and power supply
-Verify that the 4-, 6- or 8-pin CPU Aux power plug is connected
-Verify that the VIDEO card has a power connecter - if yes, connect the power to it!

Now, power-on  your PC.  On boot, do you have a display?
-if NO it is one of the connected devices: RAM, Power supply , video card or monitor.  So, if possible, swap ram, power supply, video card or monitor - leaving only motherboard and CPU
-if YES, then disconnect the AC electrical power, and start reconnecting each of the peripherals, devices and cables (one at a time) until the problem shows itself.  Before each of these reconnections, you need to follow the precautions above.
*** note : if the fans are running, this shows there is 12 V present from the power supply; this does not mean the power supply is ok, you still need 3.3 V and +5 V as well; and other signals.

Additional tests and things to try :
-boot without ram, it should beep; (also, without video card)
-try the bios default settings, (if possible) or clear the bios by removing AC and the bios battery
-renew the CPU heat paste, and verify that the heat sink is mounted flat on the CPU, allowing for a good thermal contact
-you can also check the motherboard for bad capacitors as shown here :   http://en.wikipedia.org/wiki/Capacitor_plague
- test parts on another  PC to know what is ok - and what not - if possible
***note :  if you are using 4 sticks - note that many boards do not run well with the ram bus loaded heavily like that, causing deterioration of signal levels and wave forms ! --> so test with 2 sticks max ..

The term POST refers to the Power On Self Test  procedure - here a link  with a short explanation  http://www.pchell.com/hardware/beepcodes.shtml
Asked On
2009-11-11 at 23:41:37ID1945
Tags

no post

,

no boot

,

hardware

Topic

Computer Motherboards

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5616

Comments

Expert Comment

by: grtraders on 2009-12-12 at 01:35:44ID: 6575

My yes vote:

Well written, at least for me to understand.

Ravi.

Expert Comment

by: AnilKumarSharma on 2010-04-13 at 01:12:25ID: 13068

Good article. Yes.

Expert Comment

by: nzrasta on 2010-05-04 at 15:17:28ID: 14068

Very nice and easy to understand thank you will post my results when done.

Author Comment

by: nobus on 2010-05-04 at 23:55:27ID: 14077

thanks to all - keep voting!

Expert Comment

by: neonate on 2010-07-27 at 10:49:42ID: 17516

Well done.

Author Comment

by: nobus on 2010-08-14 at 23:40:48ID: 18213

neonate : thanks!

Expert Comment

by: cbbisu on 2010-09-16 at 10:30:30ID: 19477

Very nice

Expert Comment

by: BhanaD2 on 2010-10-17 at 05:21:11ID: 20582

Replaced Power supply - Fixed the Problem

Dal

Author Comment

by: nobus on 2011-05-19 at 03:55:01ID: 27479

tx guys!

Expert Comment

by: yamurthy on 2011-12-23 at 05:25:39ID: 33866

Nice article. Simple and easy to understand.

I did not know this!! :)
*** note : if the fans are running, this shows there is 12 V present from the power supply; this does not mean the power supply is ok, you still need 3.3 V and +5 V as well; and other signals.

Author Comment

by: nobus on 2011-12-23 at 07:29:38ID: 33868

you can say lots more on it, but then it's not a short overview :))
tx for the vote

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