PC powers itself off immediately. CPU, Mobo?

[stduc]

The story so far:

This PC, a Medion 3000, decided it would not power up a few weeks ago so I replaced the power supply. This worked for under a week. When it failed it had the same symptoms i.e. on pressing the power switch it powered up for a few seconds then shut itself down. This time I removed the heatsink, cleaned away the remains of the old heatpad, replaced it with silver grease and reassembled. Lo and behold, it powered up. This time it lasted until Wednesday. I have tried cleaning the CPU and heatsink, and tried without any grease or pad. Before each attempt I re-initialised the power supply.

Should I replace the CPU next or the motherboard? Or both? I don't think it's the power supply as changing the power supply back made no difference.

 

[garebo]

Well, just to start, NEVER run a cpu without grease or a pad, you can destroy the cpu!!


Good advice + great people = tek-tips

 

[garebo]

I take it you are using win xp?
You need to give us full info on your system, as much as you can put together quickly for us to help you.

Just off the top, i am thinking you may have a heat prob. could be cpu is shutting itself down.
Some bios have a prog inside bios where you can set it to shut down the cpu at a certain temp. does your bios have that feature?
If you had told us that you had an intel mobo then i would likely guess you do have that prog inside your bios.
Thats one of the reason to give full info.
Sometimes the setting in the bios for the cpu temp is too low and it has to be set higher and all will be well.
Sometimes the setting is ok but there is a heat problem.

If we cant fix the prob right away then in the end the thing to do is take your mobo and power supply out of your case, take out all the usb devices and pci cards that you dont need. Also make sure you know where the jumpers go that connect your mobo to your case, especially for the power\on, but write them all down for future use.

Set yourself up with just the power supply, monitor, video card or video built into the mobo, 1 stick of ram unless its rambus, again we dont know your ram type yet, cpu with heatsink\fan installed to mobo with grease, properly, thin layer that covers cpu totally, and boot hard drive, c only, keyboard and mouse,the main power connector for sure plus 12 volt 4-pin if you have a P4 cpu, we dont know yet. Dont connect anything that you dont need to start up. That leaves out pci cards unless you need pci video, leaves out extra ram, leaves out usb externals, leaves out floppy drive and cdrom or dvd drives.
When that is all set up you use a screwdriver with a flat metal end on it and touch it to the 2 pins that your power\on switch was connected to. This shorts out just long enough to start up your computer, thats all it does. The power on switch doesnt stay on when you turn on computer, it only shorts out for a second to start the computer.

If you have had to get this far and if you have used the screwdriver and it started let us know, if it didnt, let us know.
but first, we need all the info you can give us.









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[stduc]

Fair enough.

The CPU is an Athlon of some description, I presume a 3000? How can I tell from the chip alone? I'm afraid I can't figure out who made the motherboard either!. I have tried with nothing but the motherboard and NO RAM! It made no difference. It simply powers up and then down. Not even a beep! The attempt with no grease was in sheer frustration - but I hope I did no harm as it only powered up for about 2 seconds.

I'm wondering if there is something up with the heatsink or fan. So, now I have the machine and am not working against the clock I'm thinking - Get a new heatsink - if that fails get a new motherboard (on the basis that then I'll have the documentation) and if that fails get a new CPU.

Now does that seem a reasonable plan - or am I missing something?

Thanks for everyones help.

 

[micker377]

I'd do the heatsink first (if the fan even slows down, it sends a "shutdown" signal). Next, can you "aquire" a different CPU, your board should accept just about any AMD CPU for test. I'd save the mobo for last. It's possible that the original power supply damaged the CPU.

 

[garebo]

Right off the bat, how about the other power supply? Maybe it actually is good, since you seem to have the same problem. Just a thought.
YOu can buy a tester,and we should all have one anyway, at bestbuy or compusa for about $10. They are also good for re-setting a power supply as well as letting you know it powers up.
I dont mean to argue, but actually you need to try another fan, not heatsink, right? Although if you are purchasing, then, yes, you likely have to buy both. I dont know as i deal with forums that buy, sell, so i can get any little part i want to get.
But the heatsink can only be go good if someone has really gouged the surface where it meets the cpu, right? Plus, it can even be repaired, sanded smooth again.
Now the fan, as micker377 says, if the fans bad, then you are done for. You should be able to get your hands on another fan, at least borrow one to test?
Your mobo is far down the list of possibly bad items at this point.
The mobo, you cant see any markings around or near the pci slots?


Good advice + great people = tek-tips

 

[paparazi]

I see lots of talk about Athlon heatsink and fans but nobody pointing out the two most common mistakes that people make when fitting afore mentioned coolers on this platform.

1) Socket A heatsink/fan units have a cut out in the base of the heatsink that must be positioned so it locates over the raised cam box on the CPU socket.
If fitted "the wrong way round" the CPU overheats in a matter of seconds because the heatsink is not mating squarely to the CPU core thus proper heat transfer between core and heatsink is severely compromised.
As others have said, heat paste MUST!!! be applied to the small raised core of the CPU (1 or 2 rice grains in volume)

2) The CPU fan must be plugged into the CPU header pins and not the system fan or power fan headers (the motherboard needs to sense a spinning CPU fan, if it doesn't it shuts the PC down as a safegaured) also a bad signal from the fan can have the same results.

If a CPU gets damaged the fans usually continue to spin but without any post or boot so I dought the CPU is the cause of the shut downs.

Is there any more history we should know about?

Generic cheap Power supplies are pretty poor and there is always the chance you have suffered a double failure.

Last thought, a sticking power or reset button will also cause a quick shutdown.

Martin

Martin





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[garebo]

I guess one could put it on backwards but you have to work at it to do so.
Also, didnt mention about the fan being connected as he already had this unit running for some time and it wouldnt run if connected wrong, still you have a point, 2 points actually.

What i said about the markings on the mobo, i was looking for make and model.


Good advice + great people = tek-tips

 

[micker377]

AS for the exact CPU you have, remove the CPU - clean and look carefully at the chip (may need a magnifying glass), the speed should be on the chip itself. If you can see writing, but it's faded (or burnt), I would be worrying about a heat damaged CPU.

 

[paparazi]

garebo
Believe me, we have had this discussion before, most socket A heatsinks are just as easy to fit backwards and with no extra effort.
I mentioned the fan header because if nothing else I've learned to take nothing for granted when posting, some members will post retrospectively about having removed of changed something in the PC and mention it right at the end of the discussion.

Thats why I asked: "Is there any more history we should know about?"

Martin




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[stduc]

The machine has worked fine for some 18 months. Then one day it wouldn't power up. I reset the power supply by removing the kettle lead and pressing the power button for one minute. No change. I removed all power connectors except the Mobo. It powered up for longer - but still powered itself off before booting. I replaced the power supply. It worked. I reconnected everything and assumed problem solved. It lasted half a week before going back to square one. I removed the CPU heatsink. I cleaned off the remains of the old pad and used silver gease. It powered up and stayed up. Again this lasted about half a week again when one evening it would not power up. Thats where I am at the moment. As per advice above I will get a new heatsink/fan assembly and try that next.

Whats got me beat is why did a new power supply fix it for a few days and then the next Sunday, re-attaching the heatsink fixed it for another few days? I keep wondering if I may be disturbing something that is the real cause of the problem. I have tried with without any boards/RAM. I have re-seated the video card and RAID card. (The only two cards). I have removed and reseated the RAM.

You can't fit this heatsink round the wrong way without being very stupid (maybe I am!) as it has a copper coloured circle offset on the bottom and fitting the wrong way round would mean this circle would only cover half the cpu. So I replace it the way round it was originally, which is with the copper circle covering the CPU. This means that the clip is on the power supply side.

Now I have the PC in my possession (I was restricted to trying to fix it Sundays only - as its actually my Dad's PC) I can take a bit more time.

Please take it as read that I re-set the power supply after every shut down.

Once again, many thanks for all the suggestions. I am learning more about hardware every day. I normally only add/remove cards and hard drives once in a blue moon!

 

[paparazi]

I might be way off but this could be worth checking out!
Bad capacitors can certainly cause all manner of parculiar faults, see the diagrams on the link and check yours out for similar signs.

http://www.badcaps.net/ident/

Martin

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[garebo]

paparazzi, you are right about the heatsink. More i think of it the more its true. Just because most of us that come here a lot have seen that a million times means only that.
You're on target on the rest as well.

I think the caps would be last, but you basically state that anyway.

what about the bios? Maybe somehow the bios got messed up, doesnt recognize the cpu.

stduc - Have you noticed any changes in the bios? Have you had to fix the date at all?
Does the bios recognize the cpu on the boot screen correctly?


Good advice + great people = tek-tips

 

[stduc]

garebo - well - before I can check the BIOS I have to get it to stay up long enough. But thanks for the tip - I will check the BIOS settings as soon as I am able to. Funnily enough the clock was way out after changing the power supply the first Sunday I went up! I'm afraid I just assumed my Dad had done one of his usual tricks! They should recruit him as a Microsoft tester! - Except he never knows how he does it!!!!!!!!!

 

[stduc]

Here's a picture of the CPU. Anyone care to comment?

http://www.bville.clara.net/Photos/medion_cpu.jpg

 

[Frank4d]

Here's a picture of the CPU. Anyone care to comment?

Nice digital camera. But seriously... now that we know the processor part number, it should be running 333MHz FSB with a internal multiplier of 13. Check the MOBO clock speed which should be 166MHz. If it is set to 200MHz, you would be overclocking the CPU which could cause it to overheat.

 

[stduc]

[blue]Frank4d[/blue] Nice digital camera. But seriously...

Bit of a catch22 that - since I need to get it working first!

The bad news is a new heatsink/fan made no difference. On advice from this forum I also got myself a power supply tester. It verifies the power supply is good.

The good news is - there is no good news (yet!)

I guess its a new CPU/motherboard next!

 

[paparazi]

Measuring up what has gone before it looks like the CPU is top of the most likely list (had an XP2.2 with these exact same symptoms only yesterday) intermittant boot, got progressively worse untill it wouldn't boot at all.
Changing the CPU was an istant fix, on this occasion.

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[stduc]

Finally found the manufacturers id on the motherboard. It's a microstar MS-6716. I searched the web for info on this board. including MSI's site

http://www.msi.com.tw/index.htm

- but found nothing useful. Just a ton of posts in German! Does anyone have the URL for the documentation?

 

[mdwebneck]

I looked all over too and while I found a few hits on 6716, none of them led to support material and I searched for that number on more than one language supported MSI site and all gave back "product does not exist",
nice of them, huh?
the closest number that I found support for was 6712.

http://www.msicomputer.com/product/p_spec.asp?model=KT4VL&class=mb