Power stuttering and warning sirens - doesnt sound good

[chrisps]

Hi,

About 4.5 years ago we got a desktop pc (P3 733, Tyan P3 Mobo, 256mb RAM, GeF2 etc)

About two years after that we built our own pc, scavenging some of the componants (hdd and gfx card)

A week ago, we bought a new hdd and gfx card for the system, with the view to using it as a linux routing / file serving box for the computer in our house

We put the new hard disk in (80Gb Deskstar), and put the GeF2 (which for the past 2.5 years has been in our custom built pc) back into the original 733

It all seemed to boot fine, but the system kept completely freezing during the install of linux (freezing to the extent nothing at all was being outputted from the graphics card, and the power button didnt work at all - ie even holding it in for 4 seconds didnt power off the system - only switching it off at the wall worked)

Seeing as it seemed to crash during hard disk activity, we reseated the hard disk power and ide, and tried again, and it appeared to be fine - no freezes. Great!

However, the next day, we turned it on, and after about 1 second, we started getting a warning siren (a long beep, then a break, then a long beep etc)... According to the motherboard manual, this was "probably a memory problem" so we reseated the memory, turned it back on, and it worked fine

Then after about 2 days of use, the complete freeze re-occured, same thing - had to un plug it from the wall.

However, when we pluged it back in (after about 30 seconds), but before we pressed the power button, horrible stuttering noises started getting emmited, and the powerlight rappidly flashed on and off. We turned it off at the wall rather quick, and took the side off.

We turned it back on at the wall (but not pressing the soft power button on the pc), and for about 10 seconds, it appeared normal, but then slowly the stuttering started with the power light flashing, and the noise getting worse and worse... we also noticed the P3 fan was spinning up, then very abruptly, it all stopped and went back to normal. Slightly perplexed we pressed the soft power button, and everything started to spin up as normal, but nothing was being output from the graphics card... then about a minute later the monitor suddenly sprung into life, and the computer made the normal short boot beep, and it seemed to operate as normal... even after several shutdowns and power ups, it seems totally normal

We dont have a clue what is going on here - can anyone think of what could be happening?

Thanks, and sorry for the long post!

 

[edfair]

You have a power supply that is shortly going to upchuck, possibly taking other parts with it.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[chrisps]

Thanks for the reply, but is that definitely the problem?

How could a psu cause a computer to seemingly turn on and off very quickly without even pressing the power button? Surely doesnt the motherboard control that?

Thanks!

 

[edfair]

There is a signal coming out of the power supply called "power good". That signal controls the clock chip on the M/B, which in turn allows the processor to work. This is the timing chip, not to be confused with the CMOS clock.

There is a keepalive circuit on the M/B, powered by a separate power supply, that is responsible for energising the remainder of the power. Any problem here would have dropped main power.

You could have problems on the M/B that could cause the main power to come and go, but generally any problems there are solid failures.

The slow to start failure and the siren sounds are symptoms of the clock chip either not starting or stopping during post.




Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[chrisps]

right ok thanks - so the system powering up and down without even having the power button pushed could be caused by this timing circuit? - i have a very old (about 9yrs to be precice) psu in the loft - i will see if it has the right connectors, and try replacing it

 

[edfair]

No, the powering up and down is probably an independent failure of the power supply. The timing circuit mentioned is for the internal working of the processor and associated busses and peripheral chips.

Any power supply around 9 years old is probably AT type, you have ATX type. You'll know when you see a power cord and switch attached.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[chrisps]

No, the powering up and down is probably an independent failure of the power supply."

But most likely still to be the psu?

I have found a cheapish PSU with decent reviews online, so i think i might give that a go rather than risking the 9yr old one i have

 

[garebo]

As Edfair said, your 9 yr old power supply will likely be an AT and no good for your ATX motherboard. Of course, the main power connectors will be different so you cant make a mistake anyway.

I do believe its your power supply, but just before getting a new power supply, have a good look at the power-on switch and trace the wires from the case to where its connected on the motherboard. Make sure the wires are "nicked" or cut in some way. Another way to go would be to disconnect the power-on switch right where it fits onto the motherboard, just unhook it there and then take a standard screwdriver and touch the screwdriver to the 2 points on the motherboard where you just took off the power-on connector.
The screwdriver will do the EXACT same job as the power-on switch. If your computer boots up fine then its the switch that is bad and not your power supply. Beats paying for a new power supply if you dont need one!
If your computer behaves exactly the same way with the screwdriver trick then you likely need a new power supply.

However, I dont understand what you mean about stuttering noises. therefore, just one more idea. Use only one good stick of ram if you are using more than one, and try each stick one at a time. Also, have you had the heatsink\fan assembly off of the cpu? If so did you apply new thermal paste? And have you checked all your cables, taken them off and put them back on to make sure they are all on well, same thing with any pci or agp cards.




Good advice + great people = tek-tips

 

[chrisps]

Thanks for the comprehensive reply!

I actaually tried disconnecting the power button, and it did exactly the same thing - before i had touched any of the contacts, so obviously something dodgy is going on.

I am pretty sure my RAM is ok - I did a memcheck on it, and it passed, so unless there is some intermittent fault there, i dont think it is that.

Havent ever touched the cpu - as I say, it is about 4.5 years old, and i havent touched it since the day we bought it

I have disconnected all cables and re-plugged, except for the mobo power socket, as that just wouldnt budge

Your right about the PSU - it is the wrong type But i have found one that I can get for £14.99 inc. postage & packing, so I might try that

With the stuttering noises, I think they are caused by the hard disk or possibly cd drive starting to spin up, then stopping, then starting to spin up, then stopping etc in very rapid succession - the p3 fan is also doing a similar thing - ie spinning up then stopping. This is before the power button has been pressed, and happened even with the power button pulled out.
The thing is, it is fine now - if i plug it in, it will behave totally normally - it is very intermittent. When it is working, it works perfectly - it is very fast and responsive, no lag to speak of when loading KDE, or accessing large files. However in a couple of days it could go back to either doing random freezes, warning sirens, or this "stuttering"

Thanks again!

Chris

 

[garebo]

Did you try the screwdriver trick yet?
Course its hard to say anyway if its intermittent as you say.
As for power supply, give us the web page so we can see what power supply it is. At only 14.99 it may not be a great unit to buy, but with money differences its harder to tell, so lets see what you have picked out. Its better to get a better ps and then just keep that one for when you build a newer system.

It does seem like your power supply is going bad, though. I would just like to rule out the switch as switches are so darn cheap and they do go bad. I had someone bring a computer in with same problems you mention and it WAS the power-on switch. I proved it by unplugging it and using the screwdriver. With screwdriver his unit booted up fine, with his power-on it caused problems, easy to diagnose, but he had to have me put all his gear into a new case as we couldnt find a new power-on switch. But, again, with your problem being intermittent maybe just getting a new power supply is in order.


Good advice + great people = tek-tips

 

[garebo]

Chrisps, you stated:
"I actaually tried disconnecting the power button, and it did exactly the same thing - before i had touched any of the contacts, so obviously something dodgy is going on."

Again, why not disconnect the power button and use a screwdriver to boot up your computer. If you can do that a bunch of times with no probs then its your power-on switch thats bad. If it works with the screwdriver, then leave it for an hour and try again, and so on. If all is well then its your power-on. You could even rig a new one up and have it come outside the case and you can use it to turn on your computer all the time. A new one would cost you a dollar or two in US funds.

Im not saying its not the power supply, but you should check the power-on first.
And it could even be both for all we know.
Maybe your power supply is like 150 watts and you have added newer components and it wont supply the extra power needed but your power-on switch could be bad as well, they are so very very cheap.




Good advice + great people = tek-tips

 

[chrisps]

Sorry that wasnt very clear - what i meant was that I disconnected the power button, so it wasnt plugged into the system at all, then switched on the wall power socket and it immediately started stuttering, even though there was absolutely nothing touching the power switch motherboard contacts

Unfortunately i dont know what wattage the power supply in that machine is - it doenst say on it anywhere. I dont howver think it is a lack of power problem, as it has almost exactly the same componants in it as when it was bought, just with a bigger hard disk. Saying that however, that system was always super unstable under win98 - crashed about 10 times a day - i always put it down to win98 though.

I doubt this power supply is great (I should point out £14.99 was including delivery - £8 without delivery!), but it has a fair few reviews, and everyone seems to be happy with it - this is the link

http://www.ebuyer.com/customer/prod...2hvd19wcm9kdWN0X3Jldmlld3M=&product_uid=20083

Thanks for the help!

Chris

 

[garebo]

You're welcome!

I would still suggest you get a better one than that.
Some of the reviews may be legit some or all may not be.
Ebay people are not stupid, they put their own reviews in or have their buddies put them in, whatever like that.
So i dont pay a lot of creedence to reviews, up to you though.

I would still go with a better one. That price just seems to low to get a decent unit, and one guy did suggest he was putting it in a P2 and not to think about using an athlon xp, his was likely more honest review!

Could you try taking the power-on off the mobo and using a screwdriver or does it always just turn on. It if does turn on, use the small black switch on the back and turn it off. This only happens as you have power directed to the system from the power supply. After a while it should stop, if you have the power-on disconnected from the mobo then it should stop coming on you before you touch the contacts. Turn off at back and wait then turn on at back and apply screwdriver.





Good advice + great people = tek-tips

 

[chrisps]

when the pc is in one of its "not working phases" it doesnt matter if the power switch is plugged into the mother board or not - it still rapidly turns its self on and off. Unfortunately the PSU doesnt have a hard off switch, so i have to use the wall switch to do that.

After a while it does abruptly stop turning its self on and off (again, regardless of whether the power button is connected)

I know what you mean about the PSU - it does seem a little cheap, but EBuyer are a fairly reputable, and large UK mail order company (they have nothing to do with EBay, and i dont see any reason why people would fake reviews on it, as it wouldnt benifit them - EBuyer is a buyer only site - you cant sell stuff on it - it is just an online shop. I suppose you could argue that EBuyer themselves might fake reviews, but i really doubt it.

I was really only thinking of getting it to see if it makes a difference - i dont want to pay £50 for a good Enermax PSU only to find that its the motherboard that has failed, not the PSU =S

Thanks!

 

[garebo]

It wouldnt hurt to have a backup unit, i forgot to mention that. You could get this one and if it works fine if not then you have a cheap test unit on standbuy, good thinking.\
I was only worried about the low price is all.
I see your point about its not seling anything, same as our pricewatch.com does the same.
So maybe reviews are fair. Still, these arent ps's for say an athlon 2800 or something like that, but good enuf for what you are running.
Makes more sense, just didnt understand your thinking, now its all out there, yes, go for it.



Good advice + great people = tek-tips

 

[chrisps]

Yer - I wont be running my main PC off it by any means! If it does fix the problem, I will probably keep it as a spare and get a decent Enermax or Antec PSU

Thanks for the help - I will post back when I have the new PSU

 

[monkeymagic25]

Chrisps:

Have you tried building your PC out of the BOX???

I agree that it could possibly be a symtom of a dodgy PSU, but could also be a short circuit on the motherboard.
So, remove the entire PC from the case, and build it on a static proof bag or something like that.

One other thing to try (if its not already been mentioned) is to Check the CPU, did you put any Putty on it, or remove the putty sticker from the heatsink before you sat it on the processor - thats caught loadsa people out that I know - if its an Intel PC, the system will work fine for a dhort period of time, but will gradually slow down and stop dead, If its AMD, it will maybe make the boot screen before it throws a 'I'm too hot wobbler' beep like mad and shut down.

 

[chrisps]

Theis PC has never been taken apart - it was bought as a unit, and the only things that have ever been taken out of it are the gfx card, the net card and the memory, never the processor

How would rebuilding the whole thing out the case help?

Thanks!

 

[ceh4702]

It is hard to make a long-distance diagnosis of a problem like this.

However, when working on an older PC you have to make the decision of whether you should spend money on the old system or purchase a new one. We cant exactly tell you something for sure.

Whith intermittent problems it might be caused by overheating alarms or the motherboard automatically slowing down till the CPU Cools off enough to continue. It might also be caused by a problem with intermittent power from the power supply or from a damaged motherboard. You see a motherboard can be damaged by a damaged power supply in some instances. House power and the power from the electric company's lines may fluctuate also.

Low power levels can really damage hard drives to the point that they have too many errors to work.

If you do not like my post feel free to point out your opinion or my errors.

 

[garebo]

I support the idea of taking it out of the box.
You do want a computer that is working properly, right?
When you develop probs with an older unit that you havent used much, best thing to do is take it out of the box, take off pci cards and such that arent needed to start up.
then take heatsink\fan off and clean it, then put it back on with fresh thermal paste on cpu.
While you are at it you can clean all the dust bunnies out of everywhere and clean the dust and grime off the fan intakes on the power supply. DONT blow on the fans, use something to block the fan from spinning and clean it with a small brush or q-tip. You can blow it all out but make sure you dont cause the fans to spin, this can cause a static overload and be harmful to the power supply.
Same thing when the fan is on the cpu, dont blow on it and turn the fan, use something to hold fan in place and then blow the dust out.
Dust bunnies have been know to cause shorts! Rare, but it happens. I have personally opened a power supply and seen where it shorted out and seen the dust and dog hair that burned up and caused the short. I asked the guy and he told me his german shepherd likes to sleep beside the computer!
I had another case where the heatsink\fan were so jammed with drywall dust that the cpu shut down from overheat.
Not saying yours is the case, but you should clean it up and eliminate possible source of your problem.
Also, shorts can develop between case and motherboard that can cause your symptoms. And the power-on button, its a 2 cent piece of hardware that can also cause problems.
So best to start all over with a clean slate on this one or any one with these symptoms.



Good advice + great people = tek-tips