Hardware problem in cruncher ...

[petrusbroder]

I have a comp built from spare parts.
Processor: AMD Sempron 2800+
Mobo: Asus A7N8X-X
RAM: Kingston ValueRam @ 400 MHz (512MBytes + 256 MBytes + 256 MBytes)
PSU: no-name-brand 350W
HDD: Samsung 80 MBytes IDE (less than 4 months old)
CD-Rom-drive ???
Graphics cards (tried several AGP and PCI-cards - see below)
BIOS-settings: default (which has worked perfectly OK until this error appeared).
Comp has not been OC'ed.
Keyboard and mouse work OK.

The comp just stopped crunching.
After rebooting it beeps, POSTs as usual, gets to the Windows XP - splash screen (just before the log-in) and then reboots spontaneously.

What have I done?
1. I have exchanged the graphics cards: the same result with three different graphics cards (which BTW work OK in other computers).
2. I have tried different RAM-sticks: no change - even with RAM which works OK in different computers.
3. I have tried a different HDDs, tried to resinstall Windows; it gets to a certain point in the installation (it reboots ...) and then it gets to the splash screen and reboots.
4. Have taken away all componets not needed: the minimalistic system has mobo, processor, one stick of 512 MBytes RAM, HDD, and one PCI or AGP graphics card - still the same symtoms.

More info:
No beep-signals (except the very first short, which indicates "all well").
RAM-test (By BIOS) without problems.
Access to BIOS without any problems.
POST without obvious problems.
Boots DOS OK


I am now convinced that the culpit may be the processor (less likely???), the mobo or the PSU. I do not have spare PSUs at home just now.
Which is more likely: Mobo or PSU-failure?
Are there other possibilities?
I can afford to get only a PSU or a mobo just now - if I need more I have to wait until June 4 or so ...

I am grateful for all input I can get.

 

[CupCak3]

did you try re-installing XP directly over your current install? The chipset drivers have have been foobared

 

[petrusbroder]

Yeah - I did that as one of the first steps ... also, if it were the chipset drivers, shouldn't a totally new installation of Win XP Pro on a new - never used before - HDD remedy the situation? I tied that too ...
I could try to reformat the HDD to FAT32 and then reinstall ... just to wipe out everything. OTOH, that looks to me like a totally new installation on a new HDD. :Q

 

[Wolfsraider]

what about a boot sector virus? i had one once that did this

 

[keeleysam]

I would try the folowing:

1. Reset the CMOS
2. Reseat the heatsink
3. Take out all but the 512MB stick of ram

 

[Rudy Toody]

My ASUS mobos had the same problems when I installed XP. It turned out to be some BIOS settings:

Hardware Memory Hole. Set it to Enabled.

MTTR Mapping. Set it to Discrete.

 

[Philippart]

My guess is that the mainboard or the PSU is damaged.

 

[Coquito]

In my experience reboots are the cause of a fluctuating, inadequate, or faulty power suppy. Heat readings(possibly faulty) leading to immediate shutdown? My older xp-m would reboot if it was doing anything intensive. I cleaned out the pile of dust inside, & now it runs nonstop.

 

[BlackMountainCow]

When I came home on Sunday morning, I found my main rig down. It would boot up once more, then die again. After, that, it wouldn't even turn on any more. And there was this stench in my room (no, not the beans from Friday!). I opened up my PSU and indeed, two caps were blown, with brown electrolytic foam all over the place.

So, from that new experience I'd say check your PSU Peter.

 

[The Borg]

I recently had a machine that booted up OK but as soon as any load was placed on it, it would continuously reboot. Found two capacitors that had swolen tops. Changed then and the machine has been running for the last month or so no problem.

 

[petrusbroder]

1. Mobo inspected - no swollen tops on capacitators or any other visible problem.
2. PSU exchanged for one known as working perfectly well (before and after the exchange): problem remains.
3. Heat sink reseated: problem remains.
4. CPU exchanged (a sempron 2800 for a sempron 3200): problem remains.
5. BIOS settings reviewed - were as Roody Toody proposed: problem remains.
6. All BIOS-settings set to factory settings, problem remains.
7. BIOS reset: problem remains.
8. Case switches checked, reseated - and before that I tried to start the comp with only the power switch connected: problem remains.

Previously checked: (see above):
9. RAM works OK (I have checked different sticks, even tried the RAM in an other computer - works OK).
10. Graphics card works OK in an other computer.
11. HDD exchanged - the original one works OK in an other computer (as a slave).
12. All other components disconnected or removed - problem remains.
13. Mouse and keyboard work OK with an other computer.

Conclusions:
1. it is not the CPU.
2. It is not the RAM
3. It is not the BIOS-settings.
4. It is not the graphics card.
5. It is not the HDD or the CD-Rom or the DVD-drive.
6. It is not the PSU.
7. It is not the case.

Thus: It must be the mobo. There may be other problems than swollen caps. The mobo (and this computer incl. all other components) has been working 24/7 since july 2002 (almost 5 years).

Is this conclusion correct in your eyes?
(I really would hate to get a new mobo and then find out that the problems remaines. Then I have to solve the problem and to build a new comp around the new mobo ... )

 

[petrusbroder]

WTF - this has taken me almost 5 hours of intens work - now it is time to decide. But I will sleep on this ... so if you have opinions what to get - please let me know.
I am inclined to get a new mobo and an as powerfull CPU I can afford - preferrably a AMD A64 2x ...

 

[BlackMountainCow]

Hehe, if

Then I have to solve the problem and to build a new comp around the new mobo

is no problem, then by all means, go for a new mobo!

 

[petrusbroder]

:beer: LoL @ BMC!

 

[TurtleBlue]

Hi, Petrusbroder

The only thing that you have not listed as being checked is the mobo's cmos battery
(revived an old 386DX dell Laptop that has been sitting in the office safe for years by installing a new cmos battery)
- batt power ok?
- contacts clean?

All other contacts (internal & external) clean (dust free)?

The only other thing is to check the caps with a special meter (they may not look damaged but may have "dried out")?

Checked the components individually on another "good" machine (if possible)?

I can understand what you are going thru, petrusbroder, I tried to revive/troubleshoot an AMD Thunderbird 1.0ghz box I built for my nephew some years ago but to no avail!

Used the salvageble parts for a budget build that is built around a AMD AM2 1.9ghz brisbain cpu to crunch for dPad currently.

Good luck! :thumbsup:

 

[petrusbroder]

Well, the other removable components have been checked on a good computer.
The contacts are clean - I have blown away the dust with compressed air.

Will check the battery - have a fitting new one in a drawer ...

 

[BadThad]

Did you try laying the mobo out on some cardboard? I know it's been running fine, but I never narrow a mobo problem down until I have it sitting bare on my bench. Did you try flashing with the last BIOS they made? Will it run windows in safe mode?

If the mobo is indeed bad, I'd be inclined to go on the cheap for a cruncher. Rather than buy a whole new setup, you should just pick up a cheap socket A mobo from the FS/T forum section....just MHO (and cheap one). LOL

 

[petrusbroder]

Problem solved:
One small capacitator was broken ... it was barely visible, but when I measured across the cap it was shortened - no capacitance at all.
So: I have now well working parts: CPU, RAM, HDD, CR-rom drive, graphics card, network card, keyboard, mouse, case with PSU.
I'll try to find a mobo locally (a socket 462 - MB, with at least 3 RAM-connectors, capable for a AMD Sempron 2800+ (or better) processor.
If you happen to have one and want to part with it (e.g. for 30 - 50 US$ incl. shipping) then you could have found a home for it.

 

[rabrittain]

Cool -- you found the problem.

:thumbsup:

 

[Wolfsraider]

Good news indeed, no amd stuff here but sorry about the mobo.

 

[Coquito]

How about $1 for a new capacitator? You can post a video of yourself sodering it on.

 

[Rudy Toody]

Originally posted by: Coquito
How about $1 for a new capacitator? You can post a video of yourself sodering it on.

Do you think we will be able to see him through the thick smoke that is sure to occur?

 

[petrusbroder]

Originally posted by: Rudy Toody

Originally posted by: Coquito
How about $1 for a new capacitator? You can post a video of yourself sodering it on.

Do you think we will be able to see him through the thick smoke that is sure to occur?

Hmm, I could, but I am way to rusty with a soldering station. :Q
And I would have to borrow/get one too.
My 100W old style soldering iron is not up for this kind of work
It would bebe fun though