Dad's PC dead!

[imported_rod]

Hi all,
A few days ago, my Dad moved the PC out of the study to paint the walls. While it was out of the study, my brother pulled heaps of dust/fluff out of the front of the case with plastic tweezers.

Anyway, now the PC won't turn on. When you connect the power, the LED on the bottom of the MoBo lights-up. When you press down on the power button, nothing happends, but when you release it, the power LED lights-up. The CPU and case fan turn for about one second, then stop. The power LED stays on though. If you press/release the button again, nothing happens. If you turn it off at the back of the PSU, and wait until the MoBo light goes-out, then you can press the power button again, which will make the fans turn a little again.

The PC is a socket478 P4 1.6GHz on an ASUS P4B-M. It has 2 optical drives, 2 hard drives, 1 stick of ram, 1 agp graphics card and 3 expansion cards.

I've tried checking for short circuits, loose connections etc.., but havent found any. Any help here people? I got no idea what to do?...

RoD

 

[Adul]

have another pc new by to test parts out? Swap power supply first to see if that is the issue. Also try reseting the bios. Also inspect the motherboard. look at the capaciters to make sure they aren't any that may have blown up, bulged out etc.

 

[imported_rod]

I can't see why anything would have blown while the PC was unplugged. The case was never even opened.

I do have another PC, but it's the one in my sig, so the PSU and optical drives are about the only things they have in common. I'll try what I can when I have a minute. (It's almost midnight here, so I'll do it tomorrow).

RoD

 

[zagood]

In order...test after each one.

Clear CMOS.

Strip it down to the bare essentials (cpu, 1 stick of ram, video) and see if you can get it to post. If it has onboard video test with that instead of AGP card.

Re-seat ram.

Switch out power supply.

If those all fail, Google "motherboard troubleshooting."

Wild guesses - power supply or mobo dead (from unplugging-plugging in power spike), something came loose when it was moved, or something got fried when your brother was poking around with tweezers (possible if it was plugged in). Go through testing step by step before you start telling your dad he needs a new machine, it may be something really simple.

EDIT: Plastic tweezers? Are you sure? Brothers always lie.

-z

 

[Nocturnal]

Unfortunately I've seen this occur many times. Where a client will have unplugged their unit to go on vacation, come back home, plug their unit in and it does not work. It seems to me that the PSU doesn't like being unplugged or some component doesn't like not having power to it for extended periods of time and thus it stops working.

I think normally when it comes down to it, it is the PSU that we have to replace. Try resetting the CMOS though.

 

[powerMarkymark]

Sounds like the PSU to me.

M@rc

 

[Operandi]

If it's a no name cheapie PSU that would be my first suspect.

Otherwise you can try tearing the system down to the bear min, CPU, RAM, video card and see if you can get it to boot that way.

 

[Bozo Galora]

sounds like psu to me - heh

 

[imported_rod]

Thanks 4 the replies guys.

The PSU is a noname brand, and it's about 5 years old now. The sticker says it has 10A on the +12V rail, which should be fine for this PC.

I'll try all the steps zagood said, and hopefully that'll help.

Also, even if he was using metal tweezers, that "shouldn't" have mattered if the power was off - he only cleaned all the crap out of the grill at the front.

Also, tried removing all the front panel headers and tried using the reset + power switches on the power contacts to switch it on, but i got the same problem every time.

I'll update this post once i've tried those steps.

RoD

 

[Operandi]

No name PSUs reserve the right to die unexpectedly for no good reason without warning it happens all the time.

 

[Sandor]

I can't remember which pins you need to connect, but you can unhook the PSU from the mobo and connect two of the pins with a paper clip- if the fan turns on, the PSU is fine.

Otherwise, remove all the non-essential cards and see if it boots. If it does, add back a card at a time. Your scenario happened to me- turns out my sound card was shorting out the mobo. Damned if I knew why, since I didn't open/move the computer for awhile before that happened, but stranger things I'm sure have happened.

 

[Operandi]

Originally posted by: Sandor
I can't remember which pins you need to connect, but you can unhook the PSU from the mobo and connect two of the pins with a paper clip- if the fan turns on, the PSU is fine.

That?s not true. I've had to replace a few PSUs that would power up just fine but refused to run the system. Replaced with a Forton-Source and all was fine.

 

[imported_rod]

All right - i just tried resetting the CMOS (unplug power > remove battery > short pads on MoBo > reinstall battery > plug-in power) and tried turning it on - no luck. Same symptoms as before. Would it matter if the back-up battery was dead? It should still POST shouldn't it?

I'm gonna strip it down now - see if that helps.

RoD

EDIT: I just tried it with it's only stick of ram, the primary HDD, and the AGP card. Still no improvement. I'll try the PSU from another computer - see if that helps. Otherwise, i dunno what the problem could be...

 

[imported_rod]

I just took apart the other computer (the one with the good PSU), and although they both have 20-pin PSU's, the colours of the wires going to the 20-pin connector are different!! Will it still be okay?

RoD

 

[P4spooky]

Here is my suggestion:

1. Unplug power and make sure no lights are on the board.
2. Disconnect ALL drives (HDD/ATAPI) from board except floppy
3. Reseat memory cards (remove farthest one from CPU if you have two installed)
4. Reseat Video card.
5. Remove ALL case wires attached to the board except the power button wires.
6. Reseat 20PIN and 4PIN power supply cables to the board.

Try to boot. Let us know what happens.

 

[Operandi]

Originally posted by: rod
I just took apart the other computer (the one with the good PSU), and although they both have 20-pin PSU's, the colours of the wires going to the 20-pin connector are different!! Will it still be okay?

RoD

ATX is ATX; it should all be the same.

 

[imported_rod]

Thanks for all the replies ppl.

It seems it was the PSU that was the problem. Replacing it with another fixed everything. It's beyond me how it can work fine for 5 years, then stop working because it's switched off!...

Anyway, thanks for the help guys.

RoD

 

[zagood]

Glad you solved it. That was actually my first guess, wanted to start you off with the easiest things to test first. Same thing's happened to me a few times, actually happened 2 weeks ago with a work computer. Opened it up, had a CrapUsa 250w PSU...on an HP machine...and all the rubber feet were gone from the bottom. Must have been a floor model or instore refurb.

Anyway, get a solid replacement for that thing. Search on the Gen Hardware section of this forum for PSU suggestions, and pay close attention to pretty much everything JohnnyGuru writes.

-z

 

[gsellis]

Originally posted by: rod
Thanks for all the replies ppl.

It seems it was the PSU that was the problem. Replacing it with another fixed everything. It's beyond me how it can work fine for 5 years, then stop working because it's switched off!...

Anyway, thanks for the help guys.

RoD

All the smoke leaked out while no one was watching it. Remember that all things mechanical and electrical really run on smoke. If the smoke leaks out, they quit working. The exception to the rule is British automobiles, which actually create smoke. If the smoke does not leak out of those, they quit working, are out of oil, or have been secretly swapped with non-British parts.

 

[GalvanizedYankee]

Originally posted by: rod
Thanks for all the replies ppl.

It seems it was the PSU that was the problem. Replacing it with another fixed everything. It's beyond me how it can work fine for 5 years, then stop working because it's switched off!...

Anyway, thanks for the help guys.

RoD

JEDEC wants 5 years service life for desktop/consumer PSUs & 10 for server/workstaion.
So you got 5 years

I bet the dead PSU would work again if warmed up first. Why? When capacitors dry-out
they can present an open circuit when cold.

Three months ago I changed out an old PSU (Works Power). The 3.3V would drop to <2.4V
when ambients were <17C and the RAM would give uber-errors. If left in stand-by over night
with the fans off, there were no errors. Once opened, it could be seen the caps had vented
for awhile and dried out.

That's my guess and I bet it's close. Open up the dead PSU for a look-see.


...Galvanized

 

[imported_rod]

I was actually guessing that it was the caps. I'm planning to open it up on the weekend and have a look inside.

BtW: I bought a Thermaltake PurePower 430W. It was the cheapest name brand PSU I could find. It should bve heaps for the computer it's in.

RoD

Originally posted by: gsellis

Originally posted by: rod
Thanks for all the replies ppl.

It seems it was the PSU that was the problem. Replacing it with another fixed everything. It's beyond me how it can work fine for 5 years, then stop working because it's switched off!...

Anyway, thanks for the help guys.

RoD

All the smoke leaked out while no one was watching it. Remember that all things mechanical and electrical really run on smoke. If the smoke leaks out, they quit working. The exception to the rule is British automobiles, which actually create smoke. If the smoke does not leak out of those, they quit working, are out of oil, or have been secretly swapped with non-British parts.

Smoke - of course! I'll make sure i glue up all the vents on the new one - let's see the smoke get out of that!

RoD

 

[Sean Maxwell]

Have had the same issue. Turned out to be a bad power supply that killed the motherboard with it. Good luck.

 

[SparkyJJO]

Change the PSU. My grandparent's PC did that.