pc turns on and then off immediately

quicky008

Technomancer
I have an old pc with the foll. config:

core 2 quad q9400,msi g31 mobo,2 gb ram,80gb HDD,frontech 450 w PSU.

It was working fine till yesterday.Today i decided to upgrade its storage and so i bought a 500 GB seagate HDD from a local store-the hdd appears to be a refurbished one.

However after i installed it and turned the pc on,it powered up for a few seconds and then turned off immediately.I tried switching it on by pressing the power button on the cabinet but it didn't work.

Then i unplugged the power cable and plugged it back and then turned it back on-again it did power up but switched off almost immediately.I observed that after it switches off on its own,it doesn't turn on until i unplug and replug the power cord,which is a bit strange.

I thought the psu might have gone bad,so i checked it by disconnecting it from the pc and shorting the green and black wires on the 24 pin mobo connector-the psu fan started spinning and it didn't turn off or display any unusual behaviour,which seems to suggest that the psu is probably ok.

I tried reseating all the peripherals on the mobo,and then attempted to turn it back on but to no avail-again the same issue occurred.

I don't understand what could have gone wrong all of a sudden-it worked fine till yesterday.I read somewhere that if a hdd is faulty or has some kind of short in it,then it might damage a pc on being connected.Is it possible the new hdd might be defective and has caused some damage to the motherboard or any other component,thereby causing it to stop working?

Please help me resolve this issue,thanks.
 
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whitestar_999

Super Moderator
Staff member
First of all never assume psu is fine just by doing the shorting pins test especially when it is a local cheap brand. I don't know about faulty hdd damaging system but there are fake graphics cards out there which can fry your system just by installing them & switching the system on.
 

patkim

Cyborg Agent
I observed that after it switches off on its own,it doesn't turn on until i unplug and replug the power cord,which is a bit strange.

Your symptoms suggests that most likely the OCP (Over Current Protection) in the PSU is kicking in and as long as it's in standby state, it may refuse to start. Hence it needs a full shutdown cycle to start off again. Try to isolate the issue by starting with min components and then adding each one by one. A paperclip test does not factor in load of the rest of the components and hence it's not that reliable. A passed test just tells you that your PSU can power on with min load of a fan so in theory it's not that bad yet.

If possible inspect the SATA data & power pins on new HDD for any possible short. Clean it a bit. Replace the SATA cable with another one. Run the system bare without the case. If the system runs with another or old HDD, mostly the new HDD has some issues mostly related to shorting on the circuit somewhere. If the HDD is otherwise bad or underpowered but no shorting issues,then generally the the PC would boot but may stall at BIOS or OS Loading stages many a times.
 
OP
quicky008

quicky008

Technomancer
Can a system turn on and off due to a faulty psu?

I have some other systems on which i could test the psu and the hdd,but i am afraid that doing so poses a risk to those components.If the hdd indeed is faulty,it could damage them irreparably as well.

The pc refuses to start even when no hdd is connected.Earlier it used to work fine with the older 80gb sata hdd.

I have decided to take the new hdd to the shop from where i purchased it for testing-if it works there,then i have to assume that it was ok all along,and the issue may be related to something else.
 

patkim

Cyborg Agent
Can a system turn on and off due to a faulty psu?
It is possible. If the PSU can not sustain the load it might shut itself off. I had a case where the PSU would clear the paperclip test but under load would refuse to start, or would start and stop soon within a few seconds.

I have some other systems on which i could test the psu
You should do it other way. The only good PSU tester is another healthy PSU. So use the other PSU from working system on this PC. Start with min load. If it boots fine, then your Frontech PSU is the culprit.

Failure in PSU, CPU or Board might sometimes give identical symptoms. System starts and stops, system starts but does not POST, or refuses to start.
 
OP
quicky008

quicky008

Technomancer
I had the hdd tested at their shop-it didn't work and caused the pc to hang at the bios splash screen.However it didn't affect their psu in any way (which was also a frontech 450w unit).


The hdd was definitely faulty-the shop owner has agreed to replace it after a few days. The only question remains now is why my system is behaving in this weird manner ie turning on and off unexpectedly.
 
OP
quicky008

quicky008

Technomancer
Well i didn't want to spend much as this was a pretty old pc, and the refurbished hdd was available for only 1100,so i went with it.
 
OP
quicky008

quicky008

Technomancer
Yesterday i borrowed a working frontech psu from someone to test my system.

After installing it the pc started in one go and there were no issues at all-i left it running overnight for 6-8 hrs.I assumed the older psu was faulty.

Today in the evening when i attempted to start it again the same problem resurfaced ie the pc turned off a few secs after it was switched on.

This is really baffling - why did it work just fine yesterday, only to come up with the same problem today once more?i dont think two psus couldn't have gone bad in a row, the latter being almost new.

Is the mobo malfunctioning somehow? Should i remove it from the cabinet and test it by individually by placing it on a non conducting surface?

Can something be causing the psu to overload /short out? Each time the pc turns off, it does not turn on again until i switch off the mains completely and turn it on again
 

topgear

Super Moderator
Staff member
My two cents : never ever run a pc with a cheapo PSU better use a cheap one form good brand. Having said that recently saw an incident of a phenom quad core rig ( friend's PC ) was not loading into windows ( Corsair VS350 ). Then HDD was not detecting. Finally was getting a message of corrupted bios. The Bios menus were not also loading fully. Weirdest I've ever seen.

Interestingly when I just thought it as a bios issue and tried fixing it with bios file on a PD I was not able to do so. The USB keyboard was working only for few moments. Enough too get into qflash menu and select bios file and after that KB stopped working. Tried with a different PS2 KB and same issue. Finally by disconnecting the discrete graphic card was able to flash the bios with onboard VGA.

Now again HDD was not loading. Finally By replacing the PSu with Vs450 everything is working fine now for her with discrete GPU in mint condition.
 
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OP
quicky008

quicky008

Technomancer
after quite a while i swapped out the older msi g31 motherboard on this pc and replaced it with a asrock 945 mobo +p4 cpu that i also had lying around for some time.This mobo does boot but the problem is i hear strange "Chiiiiii....." type noise coming from somewhere inside it occasionally-the noise seems to increase whenever some cpu intensive task is performed on that system.From a bit of googling,i learned that it could be coil whine that's emitted by ageing capacitors on the mobo.

I had previously used this mobo on another pc for some time but never had any issues-but it had been lying unused for the last 1 year or so as that system was no longer operational.

Another strange problem is that the hdd which previously used to work just fine now sometimes refuses to start up during boot-i hear the characteristic whirring noise being emitted by its platters-it seems its constantly trying to spin up but is unable to do so for some reason-it also emits a clicking sound every now and then.To confirm whether the hdd is bad or not,i tested it with another seagate hdd (albeit a faulty one with bad sectors-but without any noise related issue)-it too refuses to start up sometimes and makes that whirring noise thats associated with the disks trying to spin up unsuccessfully.

Does this indicate that i might have a bad PSU? Can a faulty psu cause such issues on a system?Should i consider replacing it with something like a VS450?
 

whitestar_999

Super Moderator
Staff member
VS450 is the minimum one should get anyway when running a low end/basic pc & if possible one should at least get CX450 which costs ~1k more.
 
OP
quicky008

quicky008

Technomancer
Cx 450 is not available here atm-i also spotted some basic atom series psus from Antec on sites like mdcomputers-but i've never heard of this particular range of psus,nor did i find any reviews of them online-are they reliable at all?

Can a bad psu cause the motherboard to emit strange noises and hdd malfunction?
 
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