Troubleshooting Power Supply Units (PSUs).

Hi here is my new one

Among all the PC components,the power supply is the most dangerous.

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It convertsthe240V walvoltage into smaler 12V, 5V and 3.3V DC allocations required by thePC. Usualy, the power supply comes with the cabinet and is backed by a warrantyso   shouldn’t have problems.


*Â Â Â Â However ,it pays to be careful and take theextra effort to verify the quality of the power supply.


*    If  purchasing it separately, opt for a brandname. Check around with your friends ,the Internet and other system APSU with allits connectors builders.


*Â Â Â Horror stories offaulty PSUs that blow up and ruin entire PCs are common.


*   A good qualityPSU will not only give  system a long lifespan,it will also help reduce the noise and heat generated inside the cabinet.

*Â Â Â

 Some commonproblems    with PSUs are:



 The power doesn’t come on


1.     No power from the walsocket :

*Â Â Â Use a live power outlet .

*Â Â Â In rare cases, the power cable may be defective and may require replacement.

*Â Â Â Â Check the power cable on another working PC.


2.    Incorrect voltageseting on thePSU:

*Â Â Â Select the proper voltage setting (220-240V)on the back of the PSU.


*   WARNING: If switched on the PC with the voltage set to10-120V and with a mains supply of 240V  mayhave blown   PSU beyond repair at worst or blown a fuse atbest.


 3.The front panel power switch’s connector tothe  mother board Is not fixed correctlyor has come of or is defective :


*Â Â Â Check the mother board manual and fix the lead (wires) from the front panel switch to the mother board correctly.

*Â Â Â Â If there is still no power , try a different lead.


4.The front panelpower switch is defective:

*Â Â Â Replace theswitch.

*   If  do not want to get a replacement ,one optionis to use the reset button.

*Â Â Â The only problemwith this is that to cut the power to the system in case of system hang setc. ,then switch of the power from the mains wall outlet rather than from the front panel.

5. The power supplyconnections to the mother board are notcorrect:


*Â Â Â Check the powerconnections from the PSU to the motherboard.

*Â Â Â Refer to the motherboard manual and identify the correct connection points.


6. Notidentified; non-PSU related problem:

*   After attemptingall the above, if the system still doesn’t power up ,it is time to look else where.

*Â Â Â Disconnect allthe drives and se if it is powering up.

*Â Â Â If the system ispowering up,then start reconnecting the drives one by one to identify which is defectivedrive.

*Â Â Â If the system isnot powering with all drives disconnected, remove the other adaptors neat a timeand checking to see if it is power in gup .

*Â Â Â Leave the video adapt or for the last.

*Â Â Â If the system is stillnot powering up, then you either have a defective PSU or a defectivemotherboard.

*Â Â Â Â If there is a burnt smell, then most probablyeither one of them has been fried.

*Â Â Â Look for burnmarks on the motherboard.

*Â Â Â Â Sometimes the PSU and motherboard may be incompatible.

*   If them other boardlooks fine, replace the PSU, sinceit’s cheaper.



 The PC powers on after the second or third try


*Â Â Â The mostly likelyproblem is that the power ok(or power good) signals sent be fore the power supplyhas stabilized.

*Â Â Â Get a better qualityPSU.

*Â Â Â In modern PCs, thepower switch is a logic device that tells the PSU to supply full power to the motherboard.

*Â Â Â The power ok signaltells the motherboard that the power supply is available and stable.

*   If the signals senttoo soon the motherboard doesn’t recognize it and stays of to protect itself.

*Â Â Â This can happenin lower quality PSUs.

*   Booting more thanonce is not recommended, and  will be better of get in  beter PSU.



 The PCpowers on but nothing happens afterthat(nobeep)Â


*Â Â Â This may be dueto the addition of new hardware that is over-taxing the power supply. Removethe last hardware component instaled and check again.

*Â Â Â Â A defective harddisk or one that is notplugedin corectly: Check the power cable to the harddisk.

*Â Â Â Sometimes it may notbe fuly pluged in.

*Â Â Â Check the hard diskon another system.



 The PC freezes or reboots suddenly


*Â Â Â 1.This couldindicate afailing PSU that is not supplying power correctly to the motherboard.

*   You may be ableto get the PSU serviced but in most cases  be better  of getting a new powersupply.

*   This could be dueto over heating of the PSU or CPU: If the PSU is over heating ,the metalcabinet may be hot to touch or might geta shock.

*Â Â Â Shut of immediately.Check if the PSU fan is working, clean or replace the fan if not working or spinningvery slowly.

*    If it’s a faulty PSU   may beable to service



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About Mohan Manohar Mekap

Mohan Manohar is a blogger from India who founded Ittech back in 2007. He is passionate about all things tech and knows the Internet and computers like the back of his hand.

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