Bad power supply?
Posted 23 November 2006 - 06:19 PM
Posted 23 November 2006 - 06:46 PM
Remove the fan from the cpu cooler if you can easily do so. Make sure the fins on the cooler are clear of dust and lint. If this machine has been overheating for any length of time, there is a very real possibility that the thermal paste between the cpu and cooler has broken down and is no longer transferring the heat away from the cpu. You can check for this by gently twisting the cpu cooler slightly. If it moves without much resistance, you should probably replace the thermal paste.
On the 8400 and several other model Dells, the cpu fan AND the psu fans are thermally controlled. If the processor is overly hot at shutdown, they will run until the cpu reaches a certain temperature and then shut down. Conversely, when you start the machine, the cpu will heat up very rapidly and the fans will race to cool it down. Without the proper thermal transfer from the cpu to the cooler, it ain't happening.
An overheated processor will not boot the system...nor will it complete the post operation. Hence, no beeps and no hard drive activity. The blinking amber means just as one would think...there's a problem. The machine seemingly wanting to start after being off for an extended period also points to the cooling issue.
Hopefully the processor has not been so hot that it has failed. Do as I suggested above and let me know what you find.
Posted 23 November 2006 - 07:09 PM
Do you think that the original P/S may still be O.K.? It was totally dead when I tried it last. Can it hurt to try it after cleaning and applying new paste?
Thanks a bunch.
Posted 23 November 2006 - 07:15 PM
Definitely...replace the paste. Apply the new paste so there are no air gaps and the entire cpu core is lightly covered. Too much is almost as bad as too little.
Then cross your fingers (that the processor is ok) and fire that puppy up.
Edited by wannabe1, 23 November 2006 - 07:16 PM.
Posted 23 November 2006 - 07:21 PM
Can I put this on a federal "AMBER ALERT"????
I tried this with the secondary power supply. I will go back to the original and get back to you shortly.
Posted 23 November 2006 - 07:32 PM
Posted 23 November 2006 - 07:34 PM
Does it go to the BIOS screen or is there no video at all?
Posted 23 November 2006 - 07:38 PM
Posted 23 November 2006 - 07:50 PM
The reckless way to approach this would be to put a new processor in it and hope for the best, To be prudent about it, I'd suggest a second opinion...preferrably from someone with diagnostic tools...to verify the diagnosis. They would test the power supply and motherboard, too.
The no post/no video points directly to the processor. I wish I'd have looked at it sooner, though the machine wasn't booting when we started, so it was probably too late already.
If you do choose to take it to someone, I would be interested in hearing the result.
Posted 23 November 2006 - 07:55 PM
Posted 23 November 2006 - 08:03 PM
Posted 23 November 2006 - 08:17 PM
Posted 23 November 2006 - 09:12 PM
You had some pretty confusing symptoms...particulary when they changed briefly. I spent the morning cruising white papers for dell mobo's, and everything kept pointing back to the processor and to heat. That's why I asked about the beeps...to determine if we had post/no video or no post/no video. A post/no video would have pointed to psu or ram. no post/no video points to processor.
Was this machine throwing fits before it got to you? Seems like this one would have given some pretty obvious signs like system hangs and shutdowns. At very least, some really rotten performance.
I learned a lot about motherboard archetecture on this problem...
Posted 23 November 2006 - 09:17 PM
Posted 23 November 2006 - 09:36 PM
The only thing this unit did before it came to me was the fan racing badly.
How can I tell if the BIOS is good? A few times it did boot to post. But I don't know how to check the BIOS without a boot.
Edited by poppyal, 23 November 2006 - 09:37 PM.
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