Can A PSU still run but not function correctly!

Mortymoose

Mortymoose

Honorary Master
Joined
May 26, 2013
Messages
13,617
Reaction score
11,762
Location
In the Namibian desert...
Greetings Intelligent folk whom reside on this knowledgeable of Boards....

Daughter's PC (Tower) is acting up, PSU was making a racket, at times it would freeze, other times, it would not boot up, sometimes I would use the old trick of unplugging the VDU let the HDD boot and then plug the power back in...

Today I took it apart, after a lot of blowing in the back of the PSU, the Grinding noise went away, I double checked all the other connections and made sure the RAM was seated correctly.... Tried to boot up, nutting,PSU she be running , but even though the screen stays dead(no signal)there is power to it, made sure all cables in correctly.....

I am thinking that the problem is the PSU, but before I rush out to my nearest General dealer, would appreciate any advise you might wish to swing in my general direction!

:confused:
 
Yes that could happen. Only way to be sure is to test with a spare unit or one from a known working pc.
 
Alternatively, if you have a multi-meter, you can test the voltage going to each point on the PSU and rule out whether any of the major points have low/fluctuating voltage.

Couple links on Google on how to test.
 
Mortymoose said:
Greetings Intelligent folk whom reside on this knowledgeable of Boards....

Daughter's PC (Tower) is acting up, PSU was making a racket, at times it would freeze, other times, it would not boot up, sometimes I would use the old trick of unplugging the VDU let the HDD boot and then plug the power back in...

Today I took it apart, after a lot of blowing in the back of the PSU, the Grinding noise went away, I double checked all the other connections and made sure the RAM was seated correctly.... Tried to boot up, nutting,PSU she be running , but even though the screen stays dead(no signal)there is power to it, made sure all cables in correctly.....

I am thinking that the problem is the PSU, but before I rush out to my nearest General dealer, would appreciate any advise you might wish to swing in my general direction!

:confused:
Click to expand...

What's the name of the PSU in question? How old is it? Does it smell funny? Musky?

Do the steps below to determine whether you need to buy a new PSU... or a whole new PC :(

1. Take out everything from the mobo but the CPU and the RAM sticks. MAKE SURE THE CPU FAN IS CONNECTED TO THE MOTHERBOARD. Start the PC. If it works, then your GPU is probably the real culprit that needs to be put down :(

2. Take out the PSU and jump-start it. If it works, then the mobo or the gpu is probably faulty.
 
Last edited:
I would recommend replacing the PSU.

noisy fan means if it stops turning (noisy) then the unit will probably over heat, and can cause other overheating.

if the voltage of the PSU is no longer steady it can cause the PC not to start, but can also damage other components....

very often it is not cost effective to repair these units.
 
Hi OP.

from what you said it sounds like the PC is starting to age rapidly. My old baby is going on 9 years now. and problems is starting to show. remember that hardware does degrade with time and use. There is no short answer to your question, yes and no PSU can and cannot cause a pc to hang.using a mutlimeter to check for voltage wont work. The PSU needs to be scoped to see if there is a faulty filter or capacitor. Minute ripples or fluctuations can cause havoc in any delicate electronic circuit.

With that being said there are also numerous filters and capacitors on the various components inside a Computer and any one of these can have the same effect.

Best you can do is keep it clean, test each component individually and make sure your software is bug free.

Good luck. PC's are expensive and now is not a good time to buy.
 
I know you checked the ram, but I would check it again, swop it around in the slots.
I would also check any cards, especially a graphic card if there one is installed and reseat them all.
You can also try to clear the CMOS. It is almost like telkom asking you to reboot your router. It is an all in one cure.

All in all, it does sound like the psu is on its way out.
Possibly the capacitors.

Yes a psu can run, without working.
The 5V rail might work, but the 12V not. That would cause the fan to work, but not feed power to the cpu, etc.
 
Last edited:
It sounds like it's likely to be either the PSU or motherboard.
I had a similar issue before and found that the 5v rail was not producing enough amperage any more. If I unplugged the harddrives, I could get into the BIOS, but it wasn't very useful... Replacing PSU sorted it out.

As far as the motherboard goes, a cracked motherboard or tin whiskers would give you similar problems. Re-seating the RAM or plugging the power cable could have caused the problem to get worse. If the motherboard is older than 5 years, the solder starts bleeding and forms tin whiskers that can short. These shorts may initially cause instability and after flexing the motherboard, could result in immediate failure.

Is there a PC speaker or similar attached? If it were a RAM seating issue or a graphics card problem, you would expect beeps.
I would start with taking out everything that's not necessary so all that is plugged in to the power is the motherboard with 1 RAM chip and the graphics card. Unplug all disk drives from motherboard and power and any USB devices (other than the keyboard).
 
Also, don't forget, what happens sometimes is that the PSU will degrade, it might start the machine up, however, once you start doing "work" on it, the CPU gets more active, as well as the HDD, so when a load is put on it, the PSU cannot cope, and will drop the voltage. This is usually things like voltage regulators or capacitors failing. Replace the PSU, they are pretty cheap.
 
FEEDBACK:

I did'nt bother searching for my Fluke, it's been a good number of years since I built up my own box's , had a suspicion, went down to the local IT shop after my morning swim , picked up a 450W PSU for R270. Took three minutes to place in the box and first time boot, nice a silent, no problem.

Thanks for the comments....

Cheers

Morty
:D
 
You must log in or register to reply here.
Back
Top
Sign up to the MyBroadband newsletter
X