New built PC, fault finding

[meldrew's_mate]

Hi all,
I'm building a new PC for my son (the last time I did this the Pentiums had just come out!), and we're having problems getting the thing to even start booting so help with the diagnosis would be appreciated.

The motherboard is Asus P5ND2 SLI EAYZ with 16x PCI Express.
The cpu is Pentium 4 3GHz socket 775.
The memory is Corsair 512Mb on a single DIMM.
The graphics card is GeForce 6600V+ 512Mb/DDR2.

The symptoms are:-
1. lack of anything except the power-on led on the motherboard.
2. The monitor shows the green ("HT on"?) lamp until the power is turned on, then it immediately goes into power saving mode (can hear the HT going off)

The monitor has been checked on another PC and found to be working.
Likewise the graphics card has been tried in another PC, not extensively, but enough to eliminate it from the problem at this stage.
The psu has been checked and all the voltages are nominally as expected. (Quick edit - the psu also has an extra block of 4 pins attached to the end of the 20 pin block, these mate with the motherboard properly)
The motherboard has dual graphics capability, the selector board is installed correctly.

It seems that either the motherboard or CPU or memory are possibly at fault, so it would help greatly if you would guide me through a process to find the faulty piece. At this stage I only want to achieve some sign of life on the monitor screen, so specifically it would help if anyone can tell me if the CPU needs to function to get the initial monitor message, likewise if the memory is necessary here. Unfortunately these three parts were bought from three suppliers and I don't want the runaround.

TIA.......MM

 

[swelec]

Check that the connections from the power up buttons on the front of the computer are connected with correct polarity ie signal and ground are not reversed on the mother board

My son recently built a similar spec computer with the same result - no screen - he had not connected a supply to the grahics card - use one of the plugs normally connected to the storage devices

 

[Doc Lenny]

Hi

Take the memory out and power up. Most Motherboards will give you an audible signal that there is no memory detected. This would suggest that the system is performing preboot checks.

Try another stick of memory if you can get one!

 

[Igorian]

You don't mention whether the case is new and more importantly, the PSU

This motherboard requires an ATX-2 PSU to cater for the PCI-E bus. A lot of PSUs come with the 20 pin molex connector, which is not (entirely) compatible with this motherboard. This is in addition to the 4 pin 12V connector. You can buy adaptors, but ASUS have a recommended list of PSUs in their manual on page 2-35.


Edit. Sorry, I see u have mentioned this.

 

[gcol]

meldrew's_mate,
You say that there's another 4 pin plug that joins with the 20pin plug to fill the 24 pin socket on the motherboard. Is there still another 4 pin plug from the PSU? Pretty sure that on the MoBo you need both the 24 pin filled and the 4 pin too.

 

[AdamW]

In my experience, this can happen for seemingly no reason at all.

So, try disassembling everything, then reassembling it, and see if that helps. and I mean everything. Remove the CPU from the mobo etc. even.

But I'd agree with the PSU checks too. I used to have a P2 that wouldn't boot up properly: turned out that the budget 235W PSU didn't cut it, and a decent 250W was enough to make it boot fully.

 

[Steve]

I have a Gigabyte 7NF-RZ mobo with a Sempron processor, the mobo had the 4-way power block too, but I left it disconnected (the PSU doesn't have the 4-way lead, it is fairly ancient!) Doesn't seem to have had any negative effects on the computer.

 

[Igorian]

I have a Gigabyte 7NF-RZ mobo with a Sempron processor, the mobo had the 4-way power block too, but I left it disconnected (the PSU doesn't have the 4-way lead, it is fairly ancient!) Doesn't seem to have had any negative effects on the computer.

The ATX12V connector provides 2 additional high current 12V rails & grounds. It was initially intended for use with P4 processors, although AMD now use it for Athlons. Your Sempron won't require this to be connected.

 

[kendor]

apart from the good advice above, one thing are you sure the monitor is actually going into powersave mode and isn't simply not being able to display a resolution being sent to it? ie too high a resolution for the monitor in question?

 

[Igorian]

apart from the good advice above, one thing are you sure the monitor is actually going into powersave mode and isn't simply not being able to display a resolution being sent to it? ie too high a resolution for the monitor in question?

When booting, a basic resolution is used in order to display the POST details. In any case, if the dude doesn't come back with more information, we're not going to be able to help him. It bugs me when people do that.

 

[buzzedwap]

As mentioned above...

Strip the PC back to basics.

mainboard / CPU+Fan / Memory and PSU (I suggest at least 450Watts)

If the mainboard has onboard VGA use this to test (perhaps if it has got this and you are plugging the monitor into the nvidia card this is the problem)

What beeps do you get? How many / Long or short beeps?

Try resetting the BIOS (should be a jumper on the mainboard or pull the battery out for 5 minutes)

Lots of new graphics cards require a power connector so make sure you have plugged this in.

Let us know how you get on.

 

[JonD]

Hi,

Disconnect the Hard Drive and any other IDE device and see if you get any video output when you try to boot, it may take a while but may come back with no bootable devices found, if this happens then it's most likely that the IDE cables are reversed.

Jon.

 

[eggplant]

as mentioned above really, if there is no sign of life at all (i.e. psu /cpu fan dont kick in) then IMO you are looking at the board or PSU - even with no CPU or ram you should see a power on. (you can test the PSU to an extent by shorting pin 14 to gnd - I usually use pin13 since its right next door - if you do this the psu should kick in)
Disconnect everything apart from the PSU even disconnect the front panel connections, short together the two pwr_on pins on the board and see if you get life (contrary to a post earlier, it doesnt matter which way the pwr_on goes (its actually one power on signal and a gnd) similarly for the reset. the power indicators are polarised since they are LED's and wont light if connected the wrong way about. I wont mention that its an idea to run the board out of the case incase theres a short.
Some boards will power on fine without additional 12V "intel plug" connected, some wont, either way, if your board has it, it has it for a reason.

 

[fathertobe]

there's a lot of good advice here meldrews_mate so post back when you've had a chance to test. (He's a busy man people so forgive him for not replying).

I'll keep an eye on the thread and see if I can help, too.

 

[meldrew's_mate]

Thanks for the copious amounts of advice, despite the long delay in replying I have read and acted on them all, and the replies posted below.

Just to re-cap, the (tested elsewhere) monitor immediately powers down the ht and goes into low power mode the moment it is connected to the graphics card; with 'puter power on or off, it makes no difference.

In desperationI've just tried it with the graphics card out of the case , with the same result. It appears the graphics card needs to signal to the monitor to get it to turn on the ht (or at least not to ground a signal from the monitor)

Swelec, have checked power-up connector, as indicated elsewhere it doesn't matter which way around it goes. There is no extra power connector on the graphics card.

Doc Lenny, there is no sound from the onboard speaker, memory in, out, or shaken all about, but thanks for trying.

gcol, there is an extra 4 pin fixed plug on the mobo next to the graphics card, no change with power fed to this or not.

crafty1289, thanks for the alternative opinion regarding the PSU.

kendor, the ht can be heard going off as soon as the 15 pin connector is plugged back into the graphics card, same result whether the card is in or out, PSU powered-up or down. And a special apology to you for making you wait so long for the reply.

buzzedwap, there is no separate power connector on the graphics card. It is (see 1st post) nVidia 6600V+ PCI-E 512MB/DDR2.

I'm on a roll now, so if anyone can help further I'm listening all day