It's a mystery: computer stalls halfway through POST

[mark_m]

My Tyan 2696 System has been running just fine for many years.

Today I went to boot it up and I got a CMOS checksum error.
I cleared the CMOS.
Rebooted.
Now the POST process checks the memory and says "passed" but just hangs there at that point. Furthermore, it shows a different value for the memory each time, and none of them are correct.
It never goes to recognising keyboard or mouse.
I've taken out all the RAM but a single stick and have tried different sticks.
I can press F2 for Setup, and the screen changes to read "entering Setup" but never does.

The NumLock key responds, so the machine hasn't hung completely.

I've removed everything but a single stick of RAM (tried several different ones) and the GPU. But it's the same.

I am mystified.

Any guesses as to what's going on?

Thanks in anticipation

Mark
__________________
Tyan Tempest 2696 in Supermicro 743T-645. 2 x Clovertown E5355, 8 x 2GB Samsung RAM, Quadro FX4800

[Dingo]

Not too familiar with these boards but since you have cleared the CMOS don't you have to reset the memory dependent on how many slots you are occupying to interleave or sequential in the bios?

[Jonj1611]

Have you changed the CMOS battery mate?

[Jay]

Nothing plugged into the com ports, printer ports etc?

[mark_m]

Have you changed the CMOS battery mate?

Yes, I have, but no improvement.....

[mark_m]

Not too familiar with these boards but since you have cleared the CMOS don't you have to reset the memory dependent on how many slots you are occupying to interleave or sequential in the bios?

If I could get into the Bios then I would!
I'm just starting up with one stick of Memory anyhow, which is a valid configuration.

[mark_m]

Nothing plugged into the com ports, printer ports etc?

Thanks. No, absolute minimum: nothing at all except 1 stick memory, Graphics Card, and KB and Mouse.

[Jonj1611]

I know its a stupid question but you havent tried flashing the bios lately have you?

Also try taking the keyboard mouse and graphics card out too. I know you wont have a picture, but you should hear the beep and see the hard drive activity if it is booting.

Its possible that the bios has been corrupted somewhat, but if you can't post and can't get into the bios to flash it, you may need a new bios chip assuming it is a fault with the bios and nothing else.

Alternatively all the ram could be damaged somehow, do you have another machine you can either try to the ram in or use the ram from?

[mark_m]

Hi Jon,

No, not a stupid question. I haven't tried flashing the bios lately.
I'll try with the KB/mouse and graphics card out too.

I think I know someone who has the same or similar MB. I'll try and test the RAM on that one.

Cheers

Mark

[MaddAussie]

Have you taken the CMOS battery out and made sure the BIOS is completely reset?

[mark_m]

Have you taken the CMOS battery out and made sure the BIOS is completely reset?

Thanks for your help.

I've removed and replaced the CMOS battery.
I've shorted the Clear CMOS pins on the motherboard, and replaced the clip in the default position.
That should have reset it, shouldn't it?

Cheers

Mark

[Dingo]

Hi Mark,

All things considered, re previous posts, may I suggest you remove the HDD connection to the MB, reset CMOS, and then see if it allows you to enter bios through F2 or Delete?.

Could be that your HDD is faulty, and causing the problem of "hang", and if that is the case then it may require a fresh install.............your HDD being the problem as opposed to the BIOS.




regards



T

[mark_m]

Thank you, but I have been starting up without HDD attached.
As I said before, starting up with just GPU, 1 stick memory and nothing else added on.

Have replaced the BIOS chip, but no success. Exactly same scenario: boots up, passes RAM, let's me press F2 to setup, but never goes any further.

Next culprit might be PSU. Will be testing that later.

Thanks all for your suggestions...

Cheers

Mark

[Jonj1611]

Where did you get a bios chip from? Was it the exact same spec as the one in your mainboard?

[Kumagoro]

have you tried leaving the battery out over night. I once had a machine which when the overclocking went too far etc woulnt wipe out with a reset or the battery out even for an hour.

It took several hours for it to drain out completetly.

[mark_m]

Where did you get a bios chip from? Was it the exact same spec as the one in your mainboard?

I got it from Grains Bios Repair in Barry. Yes, same spec and when the computer starts to boot it identifies the correct BIOS. So I'm sure it's correct, the new chip.