PC Desktop Powered Off: What Is Broken?

[Thresholds]

Hi guys,

I own this pre-assembled PC with the following specs:
http://h20564.www2.hp.com/hpsc/doc/public/display?docId=emr_na-c03364657

The other day the PC powered off while working and the power on button's led switched from green to yellow, like the system went to sleep although I have that disabled.

I tried to bring the system back online to no avail so I unplugged the power cord.

I plugged the power cord back in and the green led on the back switched on but when I clicked the frontal power on button the green led behind switched off and the system of course didn't start.

If I unplug the power cord and wait for few minutes the all process repeats: green led on the back switches on and remains lit until I try to boot the PC.

I am not very expert so the only things I tried so far were a jumper reset and a replacement of the battery and removing the hard disk and neither sorted anything.

Is there any way to determine what is at fault please?
I cannot afford a new PC at present and I'd like to repair this one if possible.

Thank you.

 

[smorizio]

pull the power supply do the green wire jumper trick.
https://www.youtube.com/watch?v=YRhaI4W8d9s&html5=1
if the power supply is working it should turn on. you then need a volt meter to read the outputs to see if there right.

 

[Thresholds]

pull the power supply do the green wire jumper trick.
https://www.youtube.com/watch?v=YRhaI4W8d9s&html5=1
if the power supply is working it should turn on. you then need a volt meter to read the outputs to see if there right.

Thank you for your help smorizio.

I did the test and the power supply did turn on: the led lit and the fan started to spin.

What could be the problem than?

Thank you.

 

[smorizio]

if you have a friend have them test the voltage output of the power supply or ass if someone has a test power supply. if the mb has a power good led is it on or flashing...a flashing led on the mb is bad power. if you can pull the gpu and one ram stick see if the mb posts. with hp or pre builts it can be there cheap power supply that fails first. google the service part number see the cost to replace it or use a standard atx power supply.

 

[Thresholds]

if you have a friend have them test the voltage output of the power supply or ass if someone has a test power supply. if the mb has a power good led is it on or flashing...a flashing led on the mb is bad power. if you can pull the gpu and one ram stick see if the mb posts. with hp or pre builts it can be there cheap power supply that fails first. google the service part number see the cost to replace it or use a standard atx power supply.

Hi again smorizio,

Unfortunately I have no chance to test other parts or have them tested.

The motherboard has no power good led unfortunately.

I don't think I have a GPU, I think it's integrated but, as I said, I am really not expert on the matter.
As for the RAM, I only have one stick: should I remove that?

So the fact that the power supply passed the paper-clip test still doesn't exclude it is not broken?

If it is of any interest, when I try to start the PC, the fan on top of the CPU spins for a second before everything powers off.

Thank you.

 

[smorizio]

if you have a local tv repair shop or if your in school that has hardware training see if someone has a volt meter and could test the outputs of the power supply when it green wired. if the power supply has a load issue...this kind of test wont show it unless you plug a fan or two on the supply see if it shuts off. on pc if there a bad cap or part there are safty (no power issue like your saying to keep the mb from posting.) try and see if there anything leaking on the mb (caps).

 

[Thresholds]

if you have a local tv repair shop or if your in school that has hardware training see if someone has a volt meter and could test the outputs of the power supply when it green wired. if the power supply has a load issue...this kind of test wont show it unless you plug a fan or two on the supply see if it shuts off. on pc if there a bad cap or part there are safty (no power issue like your saying to keep the mb from posting.) try and see if there anything leaking on the mb (caps).

I will ask a tv shop nearby if they can test the power supply although I doubt they have fans to properly test it and I have none to bring: I only have a broken laptop with the same problem as this desktop.

The capacitors look all fine with no rusting or leaking.

Considering my limited possibilities to run tests I was thinking of going ahead and buying a new power supply.
The one in my desktop has this s\n 667892-001 300W ATX which brought me to this:
http://www.amazon.com/667892-001-Supply-HP-Electronics-DPS-300AB-72/dp/B019ZCJH0W

Do I need to but the exact same product from HP or I can buy a cheaper brand maybe?
If so what characteristics do I need to look for please apart from 300W?

Thank you

 

[Thresholds]

Hi guys,

I managed to test another PSU in the PC.

The one that was in the PC is the following:
http://microdream.co.uk/pc-components/pc-components-power-supplies/hp-pavilion-p6-series-300w-atx-psu-power-supply-667892-001.html#product_tabs_additional_tabbed

The one I used to run the test is this one:
http://www.acbel.com/eng/Product.aspx?id=79&&sd=31&&pid=426

Now all the fans start regularly, the dvd drive opens and the HDD seems to boot but the monitor doesn't receive any signal so I am not sure what is wrong now.

Also all the leds on the front panel don't work and the power on button starts the PC but doesn't power it off for how long I keep it pressed (I have to remove the plug to shut it down).

I have tried several cables on the monitor with works fine with another PC so I have no clue what could be the problem now.

Any idea please?

Thank you.

 

[smorizio]

make sure all the cables are on the right pins on the mb. if they are then your looking at bad mb or cpu..may have been fried from the old power supply failing.

 

[Thresholds]

make sure all the cables are on the right pins on the mb. if they are then your looking at bad mb or cpu..may have been fried from the old power supply failing.

Hi smorizio,

I think I have placed all the cables correctly.

I have read some other threads and have also tried a RAM and CPU reset although I didn't have some new thermal paste to apply to the processor.

Buying a new PSU was fine but if I need to replace MB\CPU I might as well assemble a new PC although I have never done it before.

Can MB\CPu be tested independently?
Otherwise if nothing else can be tried I can consider this one as good as dead.

Thanks a lot for your help.

 

[smorizio]

if you have a local pc shop they cna put in a post it card into one of the pci slots and read the post codes. if it botting to see what failed.

 

[Thresholds]

if you have a local pc shop they cna put in a post it card into one of the pci slots and read the post codes. if it botting to see what failed.

Thank you smorizio,

I have checked and these post it cards are not very expensive so I am going to get one: it can always be useful for the future anyway.
As soon as I get it I will analyse the MB and report back.

Thanks a lot!