Hardware failure?

[trooper11]

Ive been pulling my hair out trying to track down a problem with my system.

Its an older htpc i have had for a few years:

MSI K8NGM2-FID motherboard
Athlon 939 cpu
3GB ram (2 x 1GB/2 x 512mb)
Seasonic 430w psu


The problem is that the system will not post at all. All i get is momentary power up, the fan on the psu and cpu spin up for a couple of seconds then it shuts off.

So far, ive tried each of my sticks of ram separately, ive bought another msi board, i bought an s939 opteron to replace the cpu, and i have another power supply. all of those tries have resulted in the same failure. All i have hooked up right now is the board, cpu, ram, and psu all sitting outside of the case.

Am I missing something here? Any suggestions would be helpful.

 

[RebateMonger]

Once common cause of the momentary power up is that you didn't connect the 12vATX four-pin power connector to the motherboard. Some older motherboards will not have that connector.

 

[jackschmittusa]

The cpu fan may not be sending a rotation signal and the mb is doing a shutdown to protect what it thinks is an uncooled cpu.

 

[tyler811]

Rebate and Monger both bring up valid reasons as to why it might happen.

Right above the cpu is a 4 pin plug is that plug in tight?

Taking out the cpu and cleaning it and the heat sink with rubbing alcohol to clean it up then reseating might work.

One thing I had was bad wiring in the case. With everything outside of the case, use a screw driver on the power pins to start not the power switch.

 

[trooper11]

this board does have a 4pin power connector and it seems to be firmly connected. This is trying two different psus as well. The board is a 24pin board, so i have that connected up along with the additional 4pin power connector near the cpu itself.

thats a good point about the fan. i didnt even consider that. ill try another fan and see if it changes anything.

i do currently have the motherboard sitting on its own, outside of the case. only the cpu, ram and psu are plugged in.

I had been using a jumper on the power switch pins and switching on the psu. could that be cuasing the problem? Is that any different from using a screw driver to do it?

 

[tyler811]

this board does have a 4pin power connector and it seems to be firmly connected. This is trying two different psus as well. The board is a 24pin board, so i have that connected up along with the additional 4pin power connector near the cpu itself.

thats a good point about the fan. i didnt even consider that. ill try another fan and see if it changes anything.

i do currently have the motherboard sitting on its own, outside of the case. only the cpu, ram and psu are plugged in.

I had been using a jumper on the power switch pins and switching on the psu. could that be cuasing the problem? Is that any different from using a screw driver to do it?

No pin jumper or screwdriver does not matter as long as you are using the correct pins.

You are getting the same results with two different mobos, power supplies, and cpus'?

 

[RebateMonger]

It wouldn't hurt to check the motherboard for bulged or leaking capacitors.

Look carefully. I've seen one small, slightly bulged, capacitor take down a motherboard.

 

[tyler811]

It wouldn't hurt to check the motherboard for bulged or leaking capacitors.

Look carefully. I've seen one small, slightly bulged, capacitor take down a motherboard.

Now if they are leaking Rebate, you need to dispose of that properly correct? You do not want that on your hands right?

 

[trooper11]

yeah, i have two msi boards, two 939 cpus, and two different power supplies. Only the second power supply is brand new, the 2nd mobo and cpu were bought used, so its not impossible that those are also faulty, i just hope that isnt the case.

all have given the same result so far. I havent tried all combitions yet though.

the common peice is the ram, which ive tried each stick seperately in the system with no difference. I guess all 4 sticks could be bad, so ill try a different stick, but thats got to be a rare thing to happen.

ill check the capacitors as well

 

[jackschmittusa]

Turning the computer on only requires momentary contact of the pins on the mb to latch it into an "on" state. Are you leaving the jumper on? Never tried that, don't know if it has an effect, but a second contact with the pins will unlatch it and shut it off.

 

[KGB]

Turning the computer on only requires momentary contact of the pins on the mb to latch it into an "on" state. Are you leaving the jumper on? Never tried that, don't know if it has an effect, but a second contact with the pins will unlatch it and shut it off.

Jack is absolutely correct here.

If you're using a jumper to short the header pins and leave it on, it's the same as leaving your finger on the start button: it will start and then promptly shut down.
The MB needs to see a momentary short to turn on and stay on.

 

[trooper11]

well i really hope thats the problem lol. it would be quite embarrasing, but ill gladly take it if it works by removing the jumper.


i guess thats why a screwdriver is a better idea since your just touching it once. ill try that when i get home and ill be quite pleased if thats all it was.

 

[KGB]

well i really hope thats the problem lol. it would be quite embarrasing, but ill gladly take it if it works by removing the jumper.


i guess thats why a screwdriver is a better idea since your just touching it once. ill try that when i get home and ill be quite pleased if thats all it was.

Let us know.