Computer troubles

Mailo · Post by **Mailo** » Mon, 4. Aug 08, 07:28

My desktop computer has quit working on me, and I'm a bit stumped.

It started with me having to push the power button several times before it finally turned on, which then turned into many times before I got a reaction, and ended with no reaction at all.

The power supply at least works partially, as keyboard, mouse and headset all have power (they light up when I switch the power supply on).

I removed everything except motherboard, cpu, fan and graphics card to check other infuences and shortcircuited the pins of the power switch on the motherboard. Not a peep.

Now I can't decide whether the power supply or the motherboard is the problem. Unfortunately I have no access to a second power supply to test it. Anyone have any tips?

Tsar_of_Cows · Post by **Tsar_of_Cows** » Mon, 4. Aug 08, 07:33

A mate of mine has an ongoing issue like this with his PC, we tried swapping out the PSU and it still happened, so our guess is the motherboard. However, neither of us can be bothered to replace it, so he just lives with giving to push the power button a few times to cold start it.

Only other thing I can think of is the CMOS battery.

pjknibbs · Post by **pjknibbs** » Mon, 4. Aug 08, 08:32

Look on the motherboard for any obvious signs of damage...I had weird symptoms like you mention which I eventually traced to a missing capacitor (you could see the black burn marks where it had gone pop). Had to replace the mobo.

G_MAN · Post by **G_MAN** » Mon, 4. Aug 08, 10:16

Hah

I was going to say that.

also look for bulged capacitors (top or bottom) and ooze of doom coming from them.

Harlock776 · Post by **Harlock776** » Mon, 4. Aug 08, 10:20

I think that I read somewhere on the net that even the best capacitors only last up to five years under optimal conditions. If you put your computer under the desk and also in one of those computer holes that some desks on one side or another you will isolate the way your pc receives and gets rid of air in a bad way. I've seen many computers stuck in those spaces which don't have adequate exhaust so the hot air they generate just gets stuck in the pc and causes those caps to swell up faster than normal.

There is also the possibility of a bad mosfet but those are sometimes harder to spot because they tend to burn out on the underside so you don't notice unless you look real close or flip the mobo over to see a burn mark on the backside of the board. Sometimes those mosfet don't even burn they just barely short out so they look physically fine but don't work. Best way to find out if you have a bad mosfet or two is plug in a really good psu something like 500 watts or more and if the board doesn't go pop right away or in about five mins it's down to something else then.

Lol I've seen those bad mosfets pop before and there is smoke from them for a while afterwards too.

xeon_1 · Post by **xeon_1** » Mon, 4. Aug 08, 11:25

I have had something like this two times before and each time it was the mobo battery that was running low.
So check the battery and if it is indeed low replace it and every should work again but don't forget to set the bios to the right settings because this will reset it.

pjknibbs · Post by **pjknibbs** » Mon, 4. Aug 08, 12:20

Harlock776 wrote:Best way to find out if you have a bad mosfet or two is plug in a really good psu something like 500 watts or more and if the board doesn't go pop right away or in about five mins it's down to something else then.

A really "good" PSU wouldn't even start up under those circumstances--they're usually designed to cut out if there's something abnormal about the load, to save both the rest of the computer and the PSU itself.

Oh, one other thing to the OP: the lights coming on doesn't mean your PSU is working. A typical PSU supplies several separate "rails" of power (typically 12V, 5V, 3.3V, and more powerful ones may have several 12V rails), and one of these can go down without affecting any of the others. The end result of that is that some things will work, because they're powered off a working rail, but others won't...

Mailo · Post by **Mailo** » Mon, 4. Aug 08, 13:39

Thanks for the feedback guys.

I removed the motherboard and checked for missing/deformed capacitors and/or burn marks, nothing to be seen.
The power supply in question is a (I at least thought so) good one, Be Quiet 500W.

I guess I'll get a new power supply, hopefully one I can return if it doesn't help.

Unfortunately it's not something I can live with, as the computer now refuses to start at all

I hope I'll find the time, since I just moved 200km last week, and we're mostly living surrounded by boxes

Red Spot · Post by **Red Spot** » Mon, 4. Aug 08, 17:31

Mailo wrote:My desktop computer has quit working on me, and I'm a bit stumped.

lol .. just got a similair problem, turn power on .. black screen but I hear my PC is doing something and the green lights on my keyboard switched on ...
reset .. nothing .. reset .. windows loading-bar appears and system hangs ..

so I blow hard into the forward fan, reset .. fixed ..

(guess I may need to clean my system

)

so get someone who can blow really hard .. maybe that works ..

Mailo · Post by **Mailo** » Mon, 4. Aug 08, 17:50

Hey, RS, long time no see

Unfortunately cleaning the system was one of the first things I tried. My case is now about 5 pounds lighter, but the damn thing still doesn't work.

I just came back from the shop where I got the parts from, they were kind enough to check the power supply, apparently it's working fine.

Which leaves me with a broken mainboard, and the decision what to do ... it's a 939 socket with an Athlon64 4000 and 1Gb DDR RAM ... I can probably upgrade that for the same money a replacement mobo ... grumble, just what I need, more expenses ... we still haven't bought all the furniture the new apartment needs ...

Al · Post by Al » Mon, 4. Aug 08, 17:56

I looked into new socket 939 mobos a couple of weeks ago and there are very few around. Its probably better to put any funds towards an upgrade, I worked out a good upgrade could be had for around £200 for mobo, cpu and ram.

Red Spot · Post by **Red Spot** » Mon, 4. Aug 08, 18:47

Mailo wrote:Hey, RS, long time no see

... we still haven't bought all the furniture the new apartment needs ...

lost track .. so to speak ..

guessing you got that title ??

2nd hand isnt an (temp) option?

Mailo · Post by **Mailo** » Mon, 4. Aug 08, 19:04

yeah, got it last october ... and finally found a (so far fantastic

) job starting June 1st, which is the reason for the move.

No, second hand isn't needed, we already got the essentials, the missing stuff are additional shelves, lamps, cupboards and so on.

Red Spot · Post by **Red Spot** » Mon, 4. Aug 08, 19:20

great .. congrats

However, I was actually referring to a 2nd hand mobo ..

esd · Post by **esd** » Mon, 4. Aug 08, 23:43

Must be the season... I had a random BSOD earlier - I went to do some various bits & bobs, screensaver came on, I come back to the computer to find it sat at the logon screen without anyone logged on. It'd rebooted without me there.

In as admin, checked the event log and it said it'd "recovered from a serious error". Checked the details and found the error - nice and helpful MSKB entry for it too: "It could be hardware, drivers or another peice of software". The only coinciding things were the screensaver kicking in and an entry in the event log saying the CD-burning service had started (for who-knows-what reason. I wasn't burning anything, GIR's Civ3 was in the drive).

It's not overheating, the system temperatures are all within normals (heck, the mobo's reporting it's a degree cooler inside the case than it is out here). I just cleaned it all out about 2weeks ago too.

Drivers? None have changed in ages.

Software? Again, no changes.

Hardware? I hope not. System's only a year old.

Random freakiness of Windows The Random? Hopefully.

I've ran a full virus scan, chkdsk'd the HDD, read over my logs, and of course spent about 3hrs running a long-overdue DvD-backup of about 20gb of photographs.

Hopefully it was just a random fluctuation in the antimatter intermix ratio...

gunman127 · Post by **gunman127** » Mon, 4. Aug 08, 23:54

Just replaced the water in my PC, with considerable complications...

I unplugged all power, drained it, then rotated and relocated the radiator, which was the whole point.

Refilled everything, fired her up (NEXIA is her name), and got the BIOS saying overclock failed... fair enough.

Loaded a saved OC profile, boot into windows... and instant BSOD.

I tried the disk in my spare PC, which caused it to fail too.

Then I put it back in the main, and remembered that the old OC profile had AHCI enabled... and this install of XP does not...

Turned AHCI off, and it boots fine, works perfectly, and idles cooler!

Now my spare rig won't boot...

Mailo · Post by **Mailo** » Wed, 20. Aug 08, 16:02

I finally admitted defeat and brought the whole thing to the shop I bought it from ... first time I couldn't repair a computer on my own, sniff.

They just called, both the PSU and the motherboard were toast.
The PSU will be replaced free of charge, and the socket 939 Athlon 64 4000+ with 1 Gb will be replaced by a dual core E7200 and 2 Gb, so at least something positive coming from this

The_Abyss · Post by **The_Abyss** » Thu, 21. Aug 08, 00:40

More than something - you've just stepped on to the next (current) generation!

egosoft.com

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Computer troubles

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