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power supply, motherboard or cpu?

By ayenilmez ·
hi all,

my desktop pc doesnt start. when I turn it on, cpu fan starts reving (possibly at highest) and that's all. nothing else happens, no bios screen or error message/sound.

notes:
- removed the ram module and it doesnt even beep on startup (normally it does)
- power button turns the system on but doesn't turn it off. pressing 5 or more seconds doesn't work either. i have to unplug from the mains.
- tried unplugging all components (hdd, optical drive and ram, still unplugged).
- removed bios battery for a bit and put it back on. those didn't help.
- cpu fan speed doesn't change, it is constantly at it's highest.
- when i plug the pc to mains first time (before pressing the power button), cpu fan starts spinning and shortly after it stops. doesnt start until i press the power button.
- when pressed to power button, led that is near power button, flashes slowy and regulary (like 1s on, 1s off).

according to these findings, what do you think causing the problem? I believe it has to be either power supply, cpu or mb.

please help me to identify the problem and resolve it.

thanks

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All Answers

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Well it would help no end if we knew what these parts where

by OH Smeg In reply to power supply, motherboard ...

But the worrying thing here is that the CPU Fan spins when you plug into the mains which sort of Indicates that the Power Supply isn't healthy and it may also tell you that the M'Board is dead.

Depending on what happened here if the PS took a large Spike from the mains and it's one of the cheap no name brands it very likely passed that spike into the case taking the M'Board along with it when it died.

You can try using a Known Good PS but if the M'Board is severely damaged it may destroy another Power Supply as soon as the unit is plugged in.

Col

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parts

by ayenilmez In reply to Well it would help no end ...

hi,
pc is hp compaq dx2200. Im not sure what make the components are. doesnt mention anything about motherboard:

see this link
http://h10010.www1.hp.com/wwpc/us/en/sm/WF06a/12454-12454-64287-321860-3328893-1844701.html

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OK as it's a HP

by OH Smeg In reply to parts

I would change the PS with a Known Good one and see if that makes any difference.

Unfortunately here you'll need to accept that the crappy PS's that come with HP Products may have resulted in a damaged M'Board and trying another PS will only result in it being destroyed. So make sure that you use a Disposable PS just in case it gets trashed.

Col

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further info

by ayenilmez In reply to OK as it's a HP

what i dont get is would faulty PS give this type of symptoms? since power button wasnt functioning to switch the system off i thought it would be the motherboard.

this pc actually was on the floor and it came to contact with water (few cm flood).

after dried completely, i used it for a bit with no problems. and now it is basically not working.

if the water damaged it, i think it wouldnt work at all. but it did.

that's why i find this a bit confusing.

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Good logic on your part

by shasca In reply to further info

If a vehicle is involved in a flood, most automobile restorers would give it the crossed fingers Vampire sign.

You are probably wise to just dispose of this, as you will have no idea as to what the next anomaly will be.

Water damage is very unpredictable. Unless you have a major investment in this system it is moneywise to move on. You are the only one that knows the extent of the water damage. Your call....

"If in doubt, throw it out"

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thanks

by ayenilmez In reply to Good logic on your part

thanks for your comments, although they are not very hope-giving:)

regards

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Didn't mean to poop on your parade

by shasca In reply to thanks

I just wanted you to stand back exhale/inhale, and make sure your effort is worth the time. As I said before if you wish to tread forward we will do anything we can to help you.

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RE: if the water damaged it, i think it wouldnt work at all. but it did.

by OH Smeg In reply to further info

Not necessarily, here it all depends on what got submerged and for how long.

The M'Boards in these things have several layers of Fiberglass and the water gets between the layers and causes corrosion. which when we are talking Electrical Items isn't a very good thing to happen.

Here you'll need to look at the actual components on the M'Board and look for signs of corrosion. Any dull solder joints or actual rust on the legs of the components soldered tot he M'Board is a very bad sign.

In the case of the electronic components corrosion can start on the legs the bits of wire that are between the actual component and where they are soldered to the M'Board and cause the component to fail completely. When it comes to Solder Joints these can stop passing electricity so a Dull Solder Joint is called a Dry Joint as it stoops passing any electrical current/signal.

As this doesn't happen immediately you can sometimes with slight water damage use the device till the full effects of the water damage take effect. After that the device is history.

But on the up side you can remove the HDD fit to a suitable USB Enclosure or Adapter Lead and get your Data off the drive if necessary and then use the drive as a Backup in an external case after you have finished recovering your data. If this is important.

Col

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it's not PSU

by ayenilmez In reply to power supply, motherboard ...

ok, with a little hope to fix this pc with minimum cost, Im bought a PSU today (I asked and they confirmed I can return within 7 days if not happy with that). saying that, it still might be good idea to use the new one as in earler posts OH Smeg mentioned that hp pcs come with crap PS.

anyway, I tried and it is not the PSU, it still does the same thing.

now i have few questions:

#1 to my understanding it would either be the mobo or cpu. is there any way to understand that whether it could be CPU? what are the chances for mb/cpu?

#2 if we cant rule that out at this stage, Im going to get a 2nd hand motherboard. I have not been into hardware that much, so I dont really know that much about them. please could you recommend a mobo? only thing i figured out so far it has to be 775, sata.

#3 does a new motherboard require any specific installation etc or do I just replace it, plug the devices and start the computer?

thanks

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Well if you had of mentioned the water up front

by OH Smeg In reply to it's not PSU

I would have advised differently. But as this has been exposed to water I would opt for the M'Board being at fault here.

#1 to my understanding it would either be the mobo or cpu. is there any way to understand that whether it could be CPU? what are the chances for mb/cpu?

As for the CPU if it's an Intel CPU I have yet found no need to replace one that has failed where other hardware has failed.

Depending on which part of this M'Board that got wet though in this case that may not apply.

Open the case remove the Heat Sink from the CPU and then the CPU and check for any signs of corrosion on the Legs of the CPU or it is is a 775 or newer Socket on the underside of the CPU and in the CPU Socket.

AMD CPU's are a different story and in every case where the M'Board has died and gone to Silicon Heaven I've had to replace the CPU as well as the M'Board. I put this down to far less capacitance being built into the AMD M'Boards than what Intel has on their Chip Sets, but there I may not be correct.

#2 if we cant rule that out at this stage, Im going to get a 2nd hand motherboard. I have not been into hardware that much, so I dont really know that much about them. please could you recommend a mobo? only thing i figured out so far it has to be 775, sata.

Well here you may be limited in what you can actually use HP buys M'Boards from different suppliers and have them built to their own Specifications. So the Back Panel Ports may be different to what standard M'Boards come as. Here I don't mean the sockets in the Big Rectangular Metal Plate but the others that do not fit into the Metal Plate or in the case of some HP Products there is no Replaceable Metal Plate in the case. If that is the case here you need to buy another M'Board that is identical to the one that you have for it to fit into the case or a new case.

But if it's a standard Layout M'Board the metal Plate comes with the new M'Board and it's just a matter of replacing the Plate in the case with the one that came with the M'Board.

It's not a good idea to ignore this plate as if you don't fit it you may run into problems with directing cooling air around inside the case. Not to mention things getting into the case that you don't want in there.

As for M'Boards personally I prefer Gigabyte Boards but not ones with On Board Graphics as these use the CPU and System RAM to generate Video and produce the worst of all things. I always prefer to use a Dedicated Video Card for anything at all but if pressed for a Budget Work Station On Board Video will do just add more RAM to get reasonable performance.

#3 does a new motherboard require any specific installation etc or do I just replace it, plug the devices and start the computer?

Well other than the above if you are going to a different type of M'Board you need to check that the Stand Offs in the case can be moved to support the new M'Board Properly not to mention not produce any short circuits, and that your Power Supply has the correct Plugs for the New M'Board. Some new M'Boards require a Supplementary 12 V DC Power Plug and depending on the maker & Model of the M'Board this can be 4. 6 or 8 pins. If you don't fit this Plug to all of the available pins or just don't have one of these plugs the M'Board will not have sufficient Voltage and may cause the Board to fail by attempting to draw too much current through the Copper tracks on the M'Board.

Another thing to consider here is that the Power Supply may be over taxed if it's not replaced even if it has the correct connectors on it.

But if the M'Board slips straight in and has all of the right connectors it should just be a job of ripping out the old fitting the new and plugging everything in and off you go.

Though you will be required to do a In Place Install of the OS as the Hardware Abstraction Layer in Windows will not have the correct Hardware listed and the system is not going to boot. Of course if you replace the M'Board with the same Make & Model this isn't an issue.

Just as an after thought you'll need to check what new M'Boards actually support. The Intel P45 and newer Chip Sets M'Boards do not support 2 floppies they only support 1 being used, which may or may not be an issue for you but the bigger one with the SATA M'Boards is if you use a IDE Optical Drive some only support the use of 1 IDE Drive on the IDE Connector. That could be important to check out if you have/need more than 1 IDE Drive.

Col

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