previously working machine suddenly won't POST!! - please help

Hi all,

If anyone has any suggestions about this problem I would very much appreciate a reply.
Here's the situation: have been running a self-built machine just fine for a couple of years - pentium III 1 GHz (slot 1), Gateway/Intel 440BX board (Jabil Tabor3, based on Intel WS440BX), 512 Mb RAM, ATI Radeon 8500 AGP card, D-Link NIC, SBLive! 5.1, Promise ATA100 controller (connected to primary HD Western Digital and secondary HD Seagate), Adaptec SCSI 2906 card connected to Minolta negative scanner. Antec TruePower 350 W supply. CD-RW and DVD-ROM are connected to the ATA-33 slots on the mainboard. Windows XP Pro with all available service packs. Has been happy for a long time (originally had a pIII 500, upgraded it last year).

Over the last couple of months, it has occasionally been difficult to power on the machine - not even a POST or video signal. The problem has been (temporarily) fixed by hitting the reset switch a bunch of times, or switching off the mains power and retrying until the thing does its POST. Once POSTed, it will continue to boot just fine.

Today - tried for an hour and it won't POST. Power is flowing through the system - all fans are going, including CPU fan. CD drives and HDs are initialized. Tried pulling out all PCI cards and just leaving the video card in - no help. Tried swapping the CPU for an old PII 266 - no go. Tried replacing the ATI AGP card for an old Rage 128 PCI card - no go.

I suspect the mainboard is dead but would love a second opinion before I go ahead and replace CPU, mainboard and memory. THis is my main machine at home and it needs to be fixed pronto!

Thanks in advance for any insight!

I would change the psu first. Just because it runs the fans doesn't mean it is supplying the correct voltages where they are needed.

thanks - I'll try using the psu from another machine I have and see if that helps. Do you think the symptoms of the last few months (occasional stubbornness / refusal to power on correctly) are consistent with a gradually dying psu - which would sometimes provide the correct voltages and sometimes not?

yup, hence my suggestion.

your suggestions are always great, NooNoo - didn't intend to doubt you! :-)

If it does turn out to be the psu, that is going to be a demerit point for Antec. Because they have a fairly good reputation, I wanted to be absolutely sure that you had read through all of the symptoms I provided in my (perhaps excessively) length first post. I think this psu is only just out of its warranty period (which, I guess, increases the chance that it will be the responsible component :-) )

I think this subject has probably been covered somewhere in the forums before, but if anyone has opinions on good/bad psus I'd love to hear them. (Probably it's like asking about hard drives. They all fail sooner or later, so viewpoints tend to be colored by whether or not yours died quickly or slowly!) Nonetheless - advice is welcome.

no one makes every single product perfectly, antec get it right more often than most though.

If it doesnt cure the problem, I'd suggest looking for bulgded and blown open capacitors on the motherboard. Sounds like a typical cap situation.

Keep us posted :thumbs2:

On HP machines, just reseating the memory or replacing it cures this problem. Had several customers with this same issue.

thanks for all the advice so far. Garak - good thought on the capacitors issue, I actually checked this as one of the first things, having had clues from other people's discussions on these forums over the last few months. They all seem OK.

I'm betting it's the PSU at the moment. During the course of trying to get the $%&^ machine to boot up yesterday, I took out all cards, including memory, and reseated them - to no avail.

Interestingly, there is still a little life in the PSU that seems to be giving problems. I was preparing to swap in another old spare PSU yesterday, when just for laughs I thought I'd try to boot the machine once more... amazingly, it came up! And I'm in fact using it right now to type this! Nonetheless, I am going to go buy a new PSU, and see if I can justify getting a new case while I'm at it - current one is beige, boring and tired :-) Maybe I'll get myself one of those pretty Antec aluminium Lanboy things :-)

installed new psu - and all powering-on and POST problems seem to have disappeared. NooNoo was right! Thanks for all the much-appreciated help. I'll file this piece of computer misbehaviour away in the back of my mind for troubleshooting in the future.

Hi everyone,
I just brought a Intel 440BX tabor3 Motherboard off of Ebay, got it home, took it out of the packet.
Put it in my case/put in all the cards and the memory, put in the CPu. Turn on computer and no Video.
I did hear three beeps.....One long and two short.
I check on the web of the Bios code and it said Video.
I have 5 video cards here. 4PCI and one AGP
and nothing show on the screen. Call the tech where the board came from....he said the board is sound and I need mto keep changing CPU, memory and video cards until it work. (Man what a looser)
I have change CPU three times.
and the memory.
Any help would be great.
Thank in Avan.
Alvin

Had this kind of problem once when I was replacing a video card that had been connected to my 440bx tabor3 board - got the same POST beeps (indicating no video). Had to reset the bios (by taking the battery out of the mainboard and leaving it a good 30 mins for any charge to dissipate) to cure the problem. Once that was done,everything worked OK for me.

I would suggest doing the reset, then powering on the machine with only CPU, memory and video. Make sure that is working OK, then add in your other PCI cards.

Incidentally - I never got back to updating this thread. I thought back in November that all my powering on and no-POST problems had been due to a bad PSU b/c when it was replaced all was well. All was indeed well for 3 weeks then I couldn't power on the machine any more. Ever. No matter how much I tried. Got frustrated, bought Tyan P4 mainboard, P4 CPU, appropriate memory - installed in same case, same PSU, same everything else - worked beautifully and still is 6 months later. So it looked like my tabor3 board was dying when I first started this thread, and then at some point afterward died completely..

Anyway - good luck Alvin, sounds like CPU, memory or video aren't the issues for you, and I don't understand why I had to reset my bios to get the stupid board to accept a new video card - these boards seem temperamental!

Quote:

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Originally Posted by ajm62

Hi everyone,
I just brought a Intel 440BX tabor3 Motherboard off of Ebay, got it home, took it out of the packet.
Put it in my case/put in all the cards and the memory, put in the CPu. Turn on computer and no Video.
I did hear three beeps.....One long and two short.
I check on the web of the Bios code and it said Video.
I have 5 video cards here. 4PCI and one AGP
and nothing show on the screen. Call the tech where the board came from....he said the board is sound and I need mto keep changing CPU, memory and video cards until it work. (Man what a looser)
I have change CPU three times.
and the memory.
Any help would be great.
Thank in Avan.
Alvin

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Quote:

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Originally Posted by invisionable

Had this kind of problem once when I was replacing a video card that had been connected to my 440bx tabor3 board - got the same POST beeps (indicating no video). Had to reset the bios (by taking the battery out of the mainboard and leaving it a good 30 mins for any charge to dissipate) to cure the problem. Once that was done,everything worked OK for me.

I would suggest doing the reset, then powering on the machine with only CPU, memory and video. Make sure that is working OK, then add in your other PCI cards.

Incidentally - I never got back to updating this thread. I thought back in November that all my powering on and no-POST problems had been due to a bad PSU b/c when it was replaced all was well. All was indeed well for 3 weeks then I couldn't power on the machine any more. Ever. No matter how much I tried. Got frustrated, bought Tyan P4 mainboard, P4 CPU, appropriate memory - installed in same case, same PSU, same everything else - worked beautifully and still is 6 months later. So it looked like my tabor3 board was dying when I first started this thread, and then at some point afterward died completely..

Anyway - good luck Alvin, sounds like CPU, memory or video aren't the issues for you, and I don't understand why I had to reset my bios to get the stupid board to accept a new video card - these boards seem temperamental!

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Thank I will take Batties out for 30 min and see if that will work. I have put together over 25 system and Motherboard. but these Tabor 3 are temperamental

Quote:

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Originally Posted by invisionable

Had this kind of problem once when I was replacing a video card that had been connected to my 440bx tabor3 board - got the same POST beeps (indicating no video). Had to reset the bios (by taking the battery out of the mainboard and leaving it a good 30 mins for any charge to dissipate) to cure the problem. Once that was done,everything worked OK for me.

I would suggest doing the reset, then powering on the machine with only CPU, memory and video. Make sure that is working OK, then add in your other PCI cards.

Incidentally - I never got back to updating this thread. I thought back in November that all my powering on and no-POST problems had been due to a bad PSU b/c when it was replaced all was well. All was indeed well for 3 weeks then I couldn't power on the machine any more. Ever. No matter how much I tried. Got frustrated, bought Tyan P4 mainboard, P4 CPU, appropriate memory - installed in same case, same PSU, same everything else - worked beautifully and still is 6 months later. So it looked like my tabor3 board was dying when I first started this thread, and then at some point afterward died completely..

Anyway - good luck Alvin, sounds like CPU, memory or video aren't the issues for you, and I don't understand why I had to reset my bios to get the stupid board to accept a new video card - these boards seem temperamental!

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Well Sir, you were right on the money.
I took the cmos bat. out for an hour and then put it back in with a plain 2mb Video card and it work.....THANK!!!!THANK a whole lot.

Alvin

Pleasure to help out. I just hope your tabor3 board lasts a lot longer than mine did (about 2 years only)... :-(