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dead mobo? I get no post no beep, no fan spin... not the PS

T

tigerbait

Diamond Member
I've had a P4 1.6a and an Asus P4S333 for a little over a year now. I took the combo out of my case, and put them in a new case, because I am selling it to a friend. It was posting fine, and I was in the middle of trying to install windows on a fresh HD. The windows install wouldn't complete...it kept getting hung up after it copied files and said to restart. Anyway, after a few reboots and reformats with MaxBlast software, the computer stopped turning on.

The green LED lights up on the mobo, you hit the power and it turns on for about half a second. (I can tell by my LED Case fan) Then nothing...if I hit power again nothing happens, not even the case fan light blink on. If I remove the power cord long enough for the standby LED on the motherboard to extinguish and plug in the power again, then I get the same half second of power where the case fan lights up. I tried another power supply with the same result, so I think I can rule that out.

So how do I determine if it is the motherboard or the CPU? And could this have been causing the problem I had the previous two hours when I couldn't get the windows install to complete?


I tried to remove the mobo from the case and run it sitting on an antistatic bag on top a box, but the same result.

I found this info, which seems to be related to my problem:

"Dead System (no POST, screen blank, no beep)
The most likely cause is a device that is shorting out the power supply. An improperly inserted memory module, a defective adapter or device can cause a short circuit. To prevent damage to a power supply, the system board must present a "POWER GOOD" signal to the power supply in 150mS or less. If this does not occur, then the power supply shuts down internally"


now how i do find the short?

THanks
 
Take everything out the case. Put the mobo on a big antistatic baggie, plug in the video card, one ram, the cpu/cooling, and the power supply. Now connect the boot pins and report back here.

IE the case can short the mobo; to rule that out, take the stuff out.

PS I've never discovered this trick to work personally, but others say this works sometimes for getting rid of shorts.
 
I often find that trying to run the motherboard outside of your case (on a piece of cardboard for example) and the bare minimum (graphics adapter, RAM) and see if that fixes things. My guess about the install not completeing would be something different, most likely bad RAM.

\Dan
 
ok guys, I tried running it outside the case, but the same result...I hear a sound from the PS like it starting to work, but then nothing. And the LED case fans just blinks shortly. Tried two power supplies, both power supplies power the fans when using the paperclip trick. Even if the CPU was dead, the fans would still spin, correct? Is this definitely the motherboard then, or should I look for another CPU to test


I guess the mobo got mad that I took it out a nice spacious Antec and put in it a Compgeeks special. 😛
 
the thing with the install was weird... I hope I don't have a bad hard drive as well as a bad mobo. It could never complete that first boot after windows setup copied all the files over and restarted itself. Tried 2000 and XP installation CDs.
 
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