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View Full Version : Oh crap. I have a SERIOUS problem... Help!



Stormwarden
27-11-2002, 12:13 PM
My new mobo arrived this morning, which I have been waiting for for about 4 months now (without a computer).

I have a teensy weensy problem - I cant get the computer to power up at all.

I installed the CPU & heatsink following the AMD guide (AXP 1800+), the ram is in DIMM1, the voltages, jumpers, yada yada are all double checked, and my graphics card (gainward GF4 MX440) is seated in the slot correctly.

The motherboard is a Leadtek Nforce2 (the pro version). The memory installed is DDR333, 256MB of it, and my power supply is supposed to be 320 watts.

I have installed motherboards before, but not an ATX one, the manual said that I should have "good conductivity" between the case, power supply, and system board (through the mounting screw holes only). This I have done. The power switch on my case seems to be working (I tested it with a multimeter to make sure it shorted the pins).

There are no other add-in cards installed, and I have gone through all of the manuals troubleshooting options, which didn't help.

What actually happens is that when I plug it in and turn it on at the back of the power supply, the little light on the network port (onboard) lights up, so I know that the motherboard is at least getting some power, but when I try to turn it on, nothing happens. No CPU fan, no power supply fans, no beeps, nothing. I have also checked to see that the power supply actually starts by shorting the green wire(pwr on) to a black wire, and it seems to start fine.

This computer I have just brought cost most of a years income for me, being 17 years old, and it doesn't go!! Please help.

(sorry for the long-winded explanation, but I am trying to show the stuff that I have already done to try to solve the prob)

tweak\'e
27-11-2002, 12:28 PM
nice to see a good explantion for a change. :)

small trick is to hit the rest button after you have pluged it in. check switchs are plugged into the right pins, i've seen manuals/mobo's with incorrectly labeled pins before.

check that you havn't shorted out the mobo to the case, or scratched the back of the board putting it in.

check cpu, psu in anothermachine.

nforce has dual ddr so you may want to stick another stick of ram in and get some better performance.

Stormwarden
27-11-2002, 12:44 PM
How am I supposed to tell if the pins are labelled incorrectly?

I also have a power on switch on my keyboard, which also doesn't work. I have tried the reset button as well.

When you mean "shorted the motherboard against the case" do you mean that the mobo should be completely insulated, or just the metal soldered pins on the underside shouldn't touch the case?

Chilling_Silence
27-11-2002, 12:48 PM
Does the Fan on the Graphic Card (If one) start going, and what about the CPU Fan (Again - If one, which there should be) or the PSU Fan?
Sounds like your PSU and motherboard are going fine. Try unpluggin all the drives (CD-ROM's etc included) and any extra card from your system, such as sound cards, but leave the LAN in if you know its going and has the little lights on too to show that its powered.
Try only pluggin in the Power-Pin in to the motherboard, the rest such as speakers can wait...
Let us know what happens, sometime a proccess of emilination is best...

Cheers

BTW, The Motherboard should only be touching the little Spcers that sit between the motherboard and the Case, not actually touching the actual case itself - It could be dangerous!


Chilling_Silence

Baldy
27-11-2002, 12:51 PM
I had a similar problem last week when my PC was as dead as a dodo.

It ended up being the front USB being shorted out - which I discovered after much wiggling of wires and components.

BALDY:-)

Stormwarden
27-11-2002, 12:53 PM
in reply to Chilling Silence:

Thanks for the reply, but as I wrote above, I have only got the GFX card plugged in. Everything else is disconnected including HDD, FDD etc.

No, none of the fans go. The mobo doesnt seem to be touching the case either, apart from the risers, and the LAN is onboard.

I have also tried unplugging RAM, video, but not the CPU. The underside of the mobo doesn't seem to be scratched either.

Stormwarden
27-11-2002, 12:54 PM
to Baldy:

What do you mean "shorted"? inside the USB socket itself, or the header pins?

None of the pins on the mobo are touching.

godfather
27-11-2002, 12:55 PM
Your power supply might be expecting a "power good" signal, that your motherboard doesn't support.

If this is the case, it would give you the symptoms you report.

If you can identify the "power good" signal wire into the power supply, supply it with +5 volts and all might work.

Stormwarden
27-11-2002, 01:00 PM
I can get the power supply to start by shorting the green wire(pin 14, i think) to a black ground wire, and the fans etc seem to go fine without a pwr_good signal.

I am beginning to think that I have a stuffed CPU/MOBO and I am dissapointed. I really needed this (after waiting for 4 months for an Nforce2) by december 9th for a big LAN party held by my friend, but If I can't get this annoying problem sorted out, I don't think I'll make it.

Can somebody tell me EXACTLY what I should have plugged in when I try to turn it on?

tweak\'e
27-11-2002, 01:27 PM
all you need plugged in is mobo (dosn't need to be in case) psu, cpu, on/off switch, reset switch and cpu fan. when it powers up you should get beeps due to no ram or video.

if that fails check the psu will work in another machine and the cpu will work. if they are ok then replace mobo.

tweak\'e
27-11-2002, 01:36 PM
one other small thing. did you have a heatsink on cpu when u first tried to fire it up?? what heatsink paste have you got on it?

nz_liam
27-11-2002, 01:37 PM
I have seen similar things before, it could be a faulty on/off power switch, try removing the switch and shorting the power pins on the Mainboard with a flathead screwdriver.


Cheers

Liam

Graham L
27-11-2002, 02:02 PM
No power supply expects a "power OK" signal. No motherboards produce a Power OK signal. Power supplies supply (;-)) a power OK signal, which the motherboards use.

Suspect your power switch.

godfather
27-11-2002, 02:05 PM
Sorry Graham...my post does read the wrong way round.

I had this trouble in the mid 80's with a PC, where to power supply had no pwr_good signal. A reset after power up worked though.

Stormwarden
27-11-2002, 02:06 PM
Already checked the power switch, and tried manually shorting the jumpers, didn't work.

The hsf is a standard AMD issue one that came with the CPU. It has generic thermal gum stuff on the bottom, and no, I was not silly enough to try to power it up without the HSF attached, although thankyou for trying to help me solve the prob.

I am taking the whole machine round to a friends tonight. while there, i'll be able to try a different cpu, ram, psu, video card and keyboard/mouse if necessary, so I should be able to find the culprit. Ho hum...

Graham L
27-11-2002, 02:38 PM
Perhaps start without even a CPU. See if you can get the fans turning. If a CD is connected (just the power cable), you should be able to open and close the slide.

Just be systematic, and DON"T PANIC !!!!! It's usually something stupid.

tweak\'e
27-11-2002, 02:45 PM
>It's usually something stupid.

like having to hit the reset switch before it will work....arghhh

Chilling_Silence
27-11-2002, 02:57 PM
Would running a CPU on a faulty MB screw the CPU if the MBoard just wouldnt power up (Not related to the problem here - just a random Q.).

Cheers

Stormwarden
27-11-2002, 02:59 PM
in reply t to Graham:

No, I cant get power to anything - I have tried plugging in a standard 12V computer fan into one of the HDD 12V connectors, which doesn't work. The only sign of life from the whole machine is that mysterious little LAN connector light. Makes me wonder if there is something fishy going on with Wake on Lan or something...

Graham L
27-11-2002, 03:06 PM
If the ethernet light is on, you've got it partly working. That's the 5V standby supply, which is on all the time. It feeds WAN devices, such as a NIC. What happens when you short the WAN connection to the motherboard? That should power up the mother board. (That is the same as the power switch ...it uses a "momentary contact" for on/off.

(Have you tried tweak'e 's suggestion of "reset"?).

Stormwarden
27-11-2002, 04:42 PM
Okay now, I've tested the ram, video, power supply in a different machine, and all are going fine. I can't test the CPU (yet, maybe).

Graham, how do I short the WAN (do you mean WON) thingy? I have a three pin header, which two do I short?

I also have a header/jumper labelled WOM (wake on modem?) neither WOM or WON/WAN are explained in the manual.

Crunn
27-11-2002, 05:25 PM
Got to go back to basics. Take the motherboard out of the case. Place on some non-conductive material, e.g. the foam out of the box. Install RAM and cpu. Make sure CPU ran pluged into correct socket (read instructions. Take PSU out of case. Plug in the MB connector. You don't need to plug anything else in at this stage. Switch the PSU on (best check the voltage selector on the back of it - should be set to 220-240 volts). As it is an ATX device you will now need to short out or bridge the power on switch. Again, see the manual for which pins these are. Just use a small screwdriver to link the two for a moment. If nothing starts up, i.e. the fans don't start to spin, then your MB is dead for all intents and purposes. Take it back and ask for a refund or another board. Not a good idea to go shorting out pins if you are not sure which is which. Puffs of black smoke and pretty lights can occur !!
Best of luck.

Crunn

Crunn
27-11-2002, 05:31 PM
Sorry, should have gone on a little longer. If she powers up at this stage. Back into the case making sure it fits snugly, nothing forced. Connect as before, i.e. as when out of the case. Retry power on. If functioning, plug your video card (sorry you probably have onboard video) in and monitor, keyboard (having turned OFF the power and for good luck pulled the plug out of the wall. ATX MB's have the power on to the MB unless physically turned off. Pulling out or plugging in cards can be a total disaster. If your machine continues to boot add more cards. Eventually you will have all the cards/plugs in. Similarly connect all the cables one at a time. This is all a bit tedious but I think you get the general trouble shooting idea.

Crunn

Graham L
28-11-2002, 03:03 PM
You shouldn't have to be struggling like this. ;-) It's possibly a faulty board. Before getting too experimental, ask the shop ... they will almost certainly be happy to check it for you.

However, Wake On Lan(Wake On Network) and Wake On Ring(Wake On Modem) allow for the power tro be turned on if the modem gets a call, or a special packet is sent on a network (usually so administartors can remotely update software when everyone else is at home, and might have turned the computers off).

The 3 pin connector has 5V, gnd and WOL or WOR pins, in that order. WOR (and the power "switch" on a separate pair of pins) use a negative pulse (from "floating" or +5V) to ground. WOL sometimes uses a positive pulse (from ground to +5V).

drys
28-11-2002, 06:28 PM
You can check an ATX power supply (be very careful here) plug in m/b and hard drive only to give enough current to switch on full power short out pins 14 & 15 to bypass wake up signal you should see the fans turn on if not suppect power supply.
Trev