AlanG

Okay.. Long story but bear with me.

HP Pavilion P7 1010a Desktop PC. About a year old if that. Been perfectly fine until today. I'll try and explain in as much detail as i can to help.

Before to-days odd goings on, a little backtrack over the last couple of weeks in case it's relevant.

I had a recent occasion where an external hard drive which is always connected to the PC, wasn't seen by the PC. The PC itself is always left on, unless there's a critical update in which case it restarts the PC.
Disconnecting the hard drive and re-connecting it, all is well. (WD My Passport type). A little odd, cause i've never had any issues at all with any of the WD passports over the years. Why the PC now didn't see the hard drive, I don't know, but it's back to normal.

Two days ago, I connected an iphone to the PC to charge it. PC didn't see the phone or charge it. Thought it was the cable, pissed about with it, nothing. Left it still connected, then, it decided to connect after a time and alls well. Subsequent disconnect, reconnect and alls normal. May be the cable, may be not, but strange.

Today, I'm on the PC when 'the screen froze. Hmm... never did that before... Tried to shut the windows that were open, nothing. Tried control/alt/delete and do it that way, nothing. Left it for 10 mins and had a coffee in case it decided to get it's act together, but no change.

Force shutdown PC and attempted to restart, nothing...

PC wouldn't power up, so a quick google on the phone and it looks like it may be the power supply.

Okay.... Disconnected and removed everything internally, one by one in case it's not the power supply but no joy, so started looking up replacement PSU's.

Just about to go out the door, when i remembered i had an old PC. Took the power supply out of the old PC and tried it on the new PC, nothing. Bollocks! Tried the new PC's power supply in the old PC and alls well. Hmm... starting to look expensive, possibly motherboard..

Took out the motherboard and for some strange reason, I decided to have one last go with the PSU before i forked out on a motherboard. It worked!
Eh? Okay... refit motherboard to case, plug in PSU, power up, all okay. Hmm...

Connect each item one at a time and re-check, all okay with the exception of one cable which looks like it goes to memory card readers. Thought this was the problem and because i don't use the readers, it's no big deal, so box up the PC, connect up to printers, hard drives, mouse etc and.......... it doesn't power up......

I disconnected all the USB devices on the back of the PC and the PC powers up. If I then connect each USB device to the PC it remains powered up.

My worry now is that if i shut down the PC, it's not going to power back up again unless i disconnect the USB devices, so the question is... eventually!!... what can you suggest is wrong with the PC? Is it still a motherboard issue?

ShayneJ

I does look like PSU on its way out if i read it correctly it looks like the total load with
all your usb devices connected is at the limit of what the psu can supply
it "may" be due to a regulator starting to fail in the psu due to its age.

but it could also be a failing motherboard again due to age.

one year may not be very old however you say the pc is on most of the time
so it has a lot of running hours clocking up and position and heat management
issues like dust build up can kill a pc or any of the bits connected to it
quite quickly.

i monitor the internal temps on my pc and see them ticking up over the weeks
and end up stripping mine down and hoovering out the case and cleaning off all
the heat sinks/fans about 5 times a year (most) of my pc is about 5 years old.
mine carries 3 hard disks 1.5 Tbite and 8 Gig ram driving 2 monitors and up to 8 usb
devices at a time with no issues.

AlanG

Thanks ShayneJ

When I had a look for replacement PSU's, I was going to buy something general at around 450W to cover what i use the PC for. Both PC's I have here have 300W max PSU's.

Was looking at something like:
Corsair VS450
or:
Antec BP430

I did clean out the PC when I opened the casing and there wasn't much build up of dust, but as you say, it can build up over time. I think I might have to do it more often, mainly because we have pretty high summer temps where we are which won't help, especially as the unit sits underneath a computer desk, although there is plenty airflow around it.

As for what motherboard to look for, I have no idea! and open to any suggestions what I should look for in one!

AlanG

Just thinking... Is there any test I can run on a motherboard to see if any part of it is failing?

mart360

Could also be memory, a failing strip of ram can have strange effects on the PC

Depending on the Bios , there may be built in diagnostics that will run tests for you.

Failing that www.majorgeeks.com they will have loads to play with from freeware to shareware


Mart

john banks

You could also measure the 12V and 5V rails when the computer is under heavy load and see if they brownout, some motherboards can monitor them IIRC, or just use a digital voltmeter if not. A powered USB hub is inexpensive and could help fault finding.

I had a few sticks of the same Crucial branded memory replaced four times over an 18 month period before I finally got a set which have lasted a few years since under much heavier use in the last year too. They never gave a failure to power up but could fail randomly with a STOP fault.

The minimum to show a display if you have integrated graphics is to have PSU, motherboard, CPU, RAM, sometimes it can then be difficult to isolate which of those is at fault.

Can you replicate the fault with certain USB items plugged in and not others? Or is it a bit more unpredictable?

AlanG

The fault happened out of the blue, I have had no issues at all with this PC until today unlike previous PC's which gave the usual symptoms you see with Windows base now and again.

I can't replicate it at all, the powering back up was purely by chance since I had already tried the PSU with motherboard only and it didn't power up, though after i took the motherboard out of the case and tried "one last time" it did power up. Odd.

With all components (apart from the card reader) re-connected, it powered up no problem. I shut the PC down again and it was only when I reconnected the USB's (2x printers, 2x hard drives, 1x keyboard, 1x mouse) that it refused to power up.
By that time i'd got fed up spending all that time faffing around, so disconnected all USB connections and powered the PC up. The PC stayed powered up with each USB connection being put back in.
I'm leaning towards a possible PSU degradation since most of the power is used on start up and it's only a 300W PSU.
I'd just like to confirm before I spend any money needlessly going round in circles. If the PC was a few years old, then fair enough, upgrade and all that, but it's only about a year old and still good spec.