Diagnostic question

[octoolguy]

I was given an HP Pavilion S5510f computer by a neighbor to see if I could bring it back to life. They were told that it "fried" the motherboard. I have been messing with computers for a lot of years and have only seen one motherboard failure and it was on one that I built. Anyway, I hooked it all up and when I press the power button I get an instant flash on the power LED and then nothing. I don't have any way to check the power supply or the motherboard other than swapping out parts. Since I don't have either one, I need a little guidance here. Can anybody give me any help? I am leaning toward the power supply but I know that the motherboard controls it. I don't get any fan operation at all. What is my next step? I would really appreciate any constructive suggestions. Thanks,

Ray

 

[aigomorla]

PSU or Board
Can also be the CPU... but not suspecting it heavily.

At this point its very difficult to diag without spare parts.
Its not Ram nor is it GPU because most likely you would hear audiable noises in beeps from pc when u powered it on.

The things u may try... try replacing the coin battery to the board.
A Failed battery can sometimes do that because your BIOS wont boot up.

Then you would need to replace the PSU....
And if those 2 dont work... then the problem lies in your core.. board / cpu / ram.

 

[octoolguy]

Thanks aigomorla. I'll give that a try. I'm hoping it's not the m/b. That would make it not repairable economically.

Ray

 

[aigomorla]

a bit of caution on replacing a prebuilt unit psu.

when u get the new psu, make sure u compare the wire color layout from the old and new.

sometimes vendors didnt use std psu's and used special ones.
So if u installed a std psu, you would fry your board due to the odd pin layout.

std = standard

 

[Charlie98]

Did you look at the capacitors on the mobo? My old Compaq did what you describe and I finally figured out those bulged caps weren't supposed to be like that...

 

[octoolguy]

Charlie98, I went and looked at all the caps and they all look good. No bulges. Thanks though. I keep having the feeling that I'm missing something but I don't know what it is.

R

 

[mfenn]

Try the paperclip trick on the PSU to see if the PSU itself powers up. If it doesn't, then you have your culprit. If it does power up, that doesn't fully clear the PSU of blame because it might fail under load. But it does at least let you rule it out in one direction.

 

[octoolguy]

Try the paperclip trick on the PSU to see if the PSU itself powers up. If it doesn't, then you have your culprit. If it does power up, that doesn't fully clear the PSU of blame because it might fail under load. But it does at least let you rule it out in one direction.

Now this is some helpful info. I always wondered if there was a way to just test the psu. Now, I can. Thanks a ton.

Ray

 

[octoolguy]

Try the paperclip trick on the PSU to see if the PSU itself powers up. If it doesn't, then you have your culprit. If it does power up, that doesn't fully clear the PSU of blame because it might fail under load. But it does at least let you rule it out in one direction.

Hey Mfenn, thanks for the help. I did the paperclip trick and the fan in the power supply turns once or twice and stops. If I keep jolting it with the clip it will spin but as soon as I stop jolting it, holding the clip in, it stops. Is this normal or is it a bad p/s?

Ray

 

[octoolguy]

Ok everybody. Update. I had an old power supply lying around and I did the paper clip test on it. It works. So, I plugged it into the computer, hooked up a monitor and it booted to BIOS. I had removed the hard drive so it wouldn't go any further. But it seems the mobo is good. A cheap fix if I'm lucky. Thanks to all for your kind assistance. And the best part is, I learned something. Fantastic. My neighbor had taken it to a "computer repair guy" and he told them it was a fried mobo and not worth fixing. So, now I feel pretty good about the whole thing. Thanks again to all.

Ray

 

[VirtualLarry]

Swapping in a known good (or new, although those aren't always 100% guaranteed to work either), PSU, is one of the first things that I do when I get an OEM branded PC in that is "dead". That, and check for something unplugged, frayed wires, and bulging caps on the motherboard.

 

[octoolguy]

Virtuallarry, thanks for your input. I learned something today. I should have known it before because when I was a mechanic I learned to always check the basics first. This computer had been taken to a local computer tech and for only $100 he diagnosed a "fried" mobo. His suggestion was to buy a new machine. So my neighbor did just that. Fortunately not from the tech. I would have suspected something if they had. Anyway, now I guess I can hang out my shingle as a computer "tech guy".

Ray

 

[mfenn]

Ok everybody. Update. I had an old power supply lying around and I did the paper clip test on it. It works. So, I plugged it into the computer, hooked up a monitor and it booted to BIOS. I had removed the hard drive so it wouldn't go any further. But it seems the mobo is good. A cheap fix if I'm lucky. Thanks to all for your kind assistance. And the best part is, I learned something. Fantastic. My neighbor had taken it to a "computer repair guy" and he told them it was a fried mobo and not worth fixing. So, now I feel pretty good about the whole thing. Thanks again to all.

Ray

Glad to help. It seems like you figured it out for yourself, but to answer your previous question: yes the PSU should run continuously as long as the paperclip is in place.

 

[octoolguy]

I really want to say thanks to all of you for helping me with this. I learned something new and now I "walk on water" in the eyes of my neighbors. You folks are the best. Thanks again.

Ray

 

[aigomorla]

yes the PSU should run continuously as long as the paperclip is in place.

this is only applicable 95% of the time... We used this trick a lot in watercooling.. and we found out sometimes the PSU requires a load.
the paper clip does not always work with every psu, because few PSU's require a -5V load to start, and others a load on the 12V...
This is why we tell people when hot starting a PSU plug at least 1 device in which can draw power.
HDD/SSD/ a LED or CCFL device....

Get a PSU tester from amazon... it doesn't need to be super expensive.. it just needs to tell you which rails are failing.
http://www.amazon.com/eForCity-24-pi...rds=psu+tester
They work because they check min voltage on each rail to see if it fails or not.
At the way you describe.. i am guessing something is wrong with the 12V rail on your PSU on how its behaving.

I use one of those guys for quick diags.... but i dont hold it as a bible... only something to tell me if a rail fails... then i use a multi meter and find out how weak the failing rail is.

 

[octoolguy]

Thanks aigomorla, I just ordered one. Should be good to have. I have seen lately a lot of the older computers that seem to have quit working but after opening the cases and giving them a good vacuuming/blowing out, they come back to life. This little tester will come in handy.

Ray

 

[aigomorla]

Thanks aigomorla, I just ordered one. Should be good to have. I have seen lately a lot of the older computers that seem to have quit working but after opening the cases and giving them a good vacuuming/blowing out, they come back to life. This little tester will come in handy.

Ray

-5V light will not light up on newer psu's... remember that...

that feature was sort of phased out.. which is why i said that paper clip trick wont work on few psu....

So if u never see the -5V light come on.. dont freak out.


Anyhow its cheap and it works... if u dont have a multi meter tho... u may want to upgrade to the thermaltake one or another company which shows actual voltage, however they cost like 4x that unit.... it will still be cheaper then buying a multimeter and tester separate tho.

http://www.amazon.com/Thermaltake-A...TF8&qid=1383259774&sr=1-2&keywords=psu+tester