New Build Not Starting Up - Any Ideas?

[beano500]

So, I've now put together my Upgraded PC.

Now just scratching my head wondering why it won't start up.

Symptoms.

Power on, fires up CPU fan, drives are powered, light come on on Mobo, no sounds, powers down a few seconds later. Not a flicker on the screen, no power to keyboard.

Set up

I have replaced Mobo and CPU (to Pentium 4 (550) and Asus), new power supply (400w and higher than mobo recommended minimum), new SATA drive, asme DDR memory, same floppy and same two other IDE optical drives. Added a few peripherals (SCSI card, card reader, etc).

Possibilities

Well I've tried the usual - check all connections, check all connections and check all connections. Jumpers all appear to be in right place. Everything appears to be getting the power it should, the CPU (whilst I haven't built a P4 before) is in the right way round and fan assembly mounted OK.

Before I go back to basics and try taking out anything unnecessary, have I missed anything obvious? Or is there anything I should try?

All ideas welcome!

[Liszt]

Start by unplugging drives, remove vga card and any other peripherals, so all you have is cpu(with fan etc) in mobo and connected to power.

Turn on.

If there is a problem should beep at you.
If seems ok, turn off and add VGA card.

If there is a problem should beep at you, show a message.

If ok, add a drive... etc

It might be your PSU is not upto the job.

[trooper1212]

I've had the same symptoms with a duff graphics card.

[Plotloss]

As you have checked, rechecked and checked again that all components are seated correctly I reckon its one of two things.

A knackered component

or

A short.

Check everything is seated correctly again though...

[beano500]

That was (sort of) going to be my next step. Got onboard graphics (but you weren't to know - I didn't say)

Do you think that a (good quality) 400w new PSU may still be not enough?

Is it possible it's the memory I've carried over - two sticks of 256 DDR2700 - the mobo is compatible with DDR and DDR2? (and I believe I put it in the right slots! )

[pdV6]

Could be as simple as the CPU fan plugged into the wrong fan header on the m/b - the BIOS may interpret this as CPU fan failure and immediately shut down.

[Plotloss]

pdV6 said:

Could be as simple as the CPU fan plugged into the wrong fan header on the m/b - the BIOS may interpret this as CPU fan failure and immediately shut down.

Good call

[Liszt]

You've got a lot of componentry on there.

If you disconnect the power to the drives and the drive cable to the mobo, and remove the cards, to see if the reduced load on the psu has any effect.

If it does add components back one at a time.

[beano500]

Very good point!

I RTFM and no - it's in the right place, and the fan powers up so it "looks" OK....

[Plotloss]

Start removing components and try powering on after each one...

[pdV6]

beano500 said:

Very good point! I RTFM and no - it's in the right place, and the fan powers up so it "looks" OK....

Is it a 3-wire or 2-wire power cable to the CPU fan. If 2, then there'll be no signal getting back to the BIOS to tell it the fan's working, so same result...

[beano500]

pdV6 said:

Is it a 3-wire or 2-wire power cable

3 - I've gone for the standard fan that comes with the P4.

[ErnestM]

You can have bad motherboards that are DOA as well, so that can be a factor. I have seen bad boards that still light the power light on the board... If all else fails, swap the board out...

ErnestM

[beano500]

ErnestM said:

You can have bad motherboards that are DOA as well, so that can be a factor. I have seen bad boards that still light the power light on the board... If all else fails, swap the board out... ErnestM

Thanks - but I think it's a dud user!

I'm getting warmer! It's the memory, I think. I blindly assumed that the current memory would be supported, but it's not.

Memory in - problem. Memory out, nice series of bleeps...

When I look, it's only DDR2100. Don't employ me to build computers, or otherwise follow simple sets of instructions!