[poppyal]

OCM770, Thanks for the reply. The ram chips are original and nothing has been added to this unit. The home it is in is basically closed what with central air and all (no moisture). I have checked the mobo and all appears to be normal - no distortions on caps, etc. and no leakage that I can find. This one is a real bummer.
poppyal1.

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I'm betting it's heat...and has been all along.

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.

[wannabe1]

I'm betting it's heat...and has been all along.

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.

[poppyal]

Maybe??? The paste on this CPU has dried and is almost crusted. Plus, it was not evenly distributed - some areas were not even covered. I will clean and re-apply new paste.

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.

[wannabe1]

Yes...definitely try the original power supply. I don't think that was the problem. By what you describe, we've zero'd in on the cause.

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.

[poppyal]

I did and it doesn't!!! Still the same. The CPU fans races on and on and there is no boot. The light on the button still stays constant amber.

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.

poppyal1.

[poppyal]

I reinstalled the original P/S. The system is connected as it was originally. I powered on and got nothing. Just a blinking amber light in the power button.

[wannabe1]

This is not sounding good, is it?

Does it go to the BIOS screen or is there no video at all?

[poppyal]

No video at all - nothing. Not even any beeps or diagnostic lights. At least the secondary P/S made the fans work.

[wannabe1]

I'm thinking the processor is toast.

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.

[poppyal]

Could putting a new processor in it harm the processor or would it just help verify the overall problem?

[wannabe1]

If you have another processor for it, give it a try. It shouldn't hurt the processor so long as the thermal paste is applied.

[poppyal]

I thought I had one, but I guess I do not. I'm don't know what to do now. I was so sure that the power supply was bad, especially since the second unit worked a couple of times. Is it possible to get just the processor checked? That would probably be the easiest and least expensive way to go from my end.

[wannabe1]

It would depend on who you take it to and the luck of the draw. If a shop happens to have a test bed for that processor, that would be the way to go. A few phone calls would tell the story on that. Most will probably ask you to bring in the machine, though.

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...

[-OCM770-]

I fyou put a new processor in there make sure its the same type and socket or else you will toast it.... Is BIOS even good?


-OCM770-

[poppyal]

wannabe1,
The only thing this unit did before it came to me was the fan racing badly.

OCM770,
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.