Computer has intermitent start up problem

[djd4n]

Hi

I have a P4 3Ghz socket 478 CPU and an intel D875PBZ mobo with 768GB RAM.

I have a very annoying problem, occasionally when the power button is pressed on the front of the case of the computer the computer fails to start. The fans twitch and the HDD LED flashes but that's it, no beeps. It is fine 90% of the time.

This problem occurs after the computer has been moved. The computer is in a rack mount case inside a flight case. It is moved around from location to location.

It seems computer will start after if it has not been moved for a while, ie left after being moved. That seems not to make sense!

I can eliminate:

The power supply: problem occurs with other power supplies in place and original power supply works on another comp

The motherboard: this has been replaced with a known working board.

The switch: the problem still occurs if the pins on the motherboard are shorted, bypassing the switch.

This leaves me with as far as i can see the CPU and the RAM.

Inside the case there are brackets for securing the PCI cards in place. These clamp onto the top of the cards to stop them wobbling.

I have moved 2 of these that were spare along and adjusted them so they now push down on the heatsink/fan of the cpu, one either side. I'm fairly sure that this will stop the CPU becoming unseated. I also reseated the CPU before hand.

I then moved the computer about to simulate what would happen in normal day to day stuff. The problem still occured!!

This leaves me believing it is the RAM that is causing the problem by becoming unseated, is this possible?

(If u have no RAM in the computer beeps)

How could i secure the RAM? silicon sealant or simliar?

Anyone had similar probelms?

 

[ManyVoicesOfMe]

I have a P4 3Ghz socket 478 CPU and an intel D875PBZ mobo with 768GB RAM.

That sure is alot of RAM.....

Anywho...considering you did the process of elimination to help narrow it down, I'm gonna guess the RAM. But RAM has a nice design to it that it locks into place quite well and in order to take the RAM out you have push those holder tabs back, so I don't think that it is a matter of how snug the RAM is in place. Try using a different pice of RAM. Most RAM sticks these days come with a lifetime warranty, so you could get a replacement....

 

[Talon0226]

Ram maybe...

I have that same CPU and mobo, I love it!I see you are running 768 mb of ram that is the first issue. Intel put four DDR slots on that board to run in pairs or just one single. So you are either using a 512mb stick and a 256mb stick or three 256mb sticks. Bad idea, this will slow down preformance and might cause issues. Second is this ram listed on the compatiblity list from intel. Also I would go to http://www.memtest86.com/ download this program, intall it to a floopy disk then run that to see if any of your sticks of ram, might be bad. Also this could be a grounding issue, might want to check your standoffs and screws. This is the best I can suggest. Good luck!

 

[djd4n]

i'd love 768GB of RAM! bit of a typo! it has 768MB obviously

Well, i have swopped the RAM and all was going well thought that had cured it, but then the problem happened again!

Which leaves only the CPU, will have to see about swopping this and then see how it goes.

I think the CPU could have an internal error and this would not be prevented by me securing it in more.

Could be to do with grounding but it has also occurred when it was in a different case.