Question Dell optiplex 750 shuts down

[Anouar1710]

Hello,
I have this dell optiplex 750 that shuts down directly after turning it on.
I checked the ram and bios battery but that wasn't the problem.
If anyone has a solution please help.
Thanks in adVance

 

[rgd1101]

psu failed? motherboard failed?

 

[Anouar1710]

psu failed? motherboard failed?

No I don't think so it just shuts down after the lights
I thought that it can be the power

 

[Anouar1710]

No I don't think so it just shuts down after the lights
I thought that it can be the power

I don't think its the motherboard nor the psu because it stopped working several months and when i tries it yesterday it worked and stopped today.

 

[jonnyguru]

I don't think its the motherboard nor the psu because it stopped working several months and when i tries it yesterday it worked and stopped today.

Parts fail. That's LITERALLY the definition of parts failing. One day they work, then the next day they don't.

Hello,
I have this dell optiplex 750 that shuts down directly after turning it on.
I checked the ram and bios battery but that wasn't the problem.
If anyone has a solution please help.
Thanks in adVance

It completely shuts down? As in: It's turns off after you turn it back on?

How did you "check the RAM"? If you power on the PC with the RAM out of the PC, does it give you the "no RAM" beep code or does it do the same "power on, then power off" issue you've been seeing?

 

[Anouar1710]

Parts fail. That's LITERALLY the definition of parts failing. One day they work, then the next day they don't.



It completely shuts down? As in: It's turns off after you turn it back on?

How did you "check the RAM"? If you power on the PC with the RAM out of the PC, does it give you the "no RAM" beep code or does it do the same "power on, then power off" issue you've been seeing?

When i take off the ram it gives the beep
And whEn i said that it failed todeay i meant that it was shutting off evry day for months and it woeked after and then it failed again.

 

[Anouar1710]

And yes it shuts down completly and sometimes it does some sort of a loop of turning on and off.

 

[jonnyguru]

When i take off the ram it gives the beep
And whEn i said that it failed todeay i meant that it was shutting off evry day for months and it woeked after and then it failed again.

Ok. Cool. That means it's "failing", or in the process. Last time I saw this behaviour it was the motherboard. If you look at the capacitors on the motherboard, do you see any with a slight buldge on the tops?

Like this:

It may be subtle, those "lines" on the tops of the caps should be completely closed. ANY bulging or "gap" means those caps are failing.

 

[Anouar1710]

I will see if any of those lines are in the tops of the caps but if there is, does it have any other solution than changing the motherboard?

 

[jonnyguru]

I will see if any of those lines are in the tops of the caps but if there is, does it have any other solution than changing the motherboard?

Afraid not.... I mean.... An electronics hobbyist like myself would actually get a bunch of replacement caps off of eBay and swap them out... but even then I don't do it to "save money" retail price on caps isn't as cheap as what the motherboard manufacturers get them for and what is your time worth?

FYI: The "lines" will be there, but notice on these "good caps" that the lines are just indentations? That's a good cap. A bad cap has these "vent" and crack open.

 

[Anouar1710]

I checked and the caps are good

 

[Anouar1710]

So i think that its not a motherboard problem then

 

[Anouar1710]

And there is another thing,
When it succesfully turns on the Pc works some minutes or so.
And then it shows the shutting off screen before going off automaticaly

 

[jonnyguru]

And there is another thing,
When it succesfully turns on the Pc works some minutes or so.
And then it shows the shutting off screen before going off automaticaly

Could it be something as stupidly simple as something overheating?

I mean... Let's check the obvious now. Is the CPU cooler securely mounted? Is the fan spinning?

 

[Anouar1710]

Yes it spins

 

[jonnyguru]

Yes it spins

That was part two of the question. 😉 Grab the heatsinks with your hands. Is it secure? It should not move at all. If it doesn't have a firm contact on the CPU, it can't cool properly.

Do you find that the days the PC works are any cooler than the days it does not?

 

[Anouar1710]

Yes it spins

Yes it has contact and i think that something is overheating.

 

[Anouar1710]

The matter that has contact with the cpu, does it have anything with the overheating??

 

[jonnyguru]

You mean thermal compound? It could dry up and not be as effective, but it shouldn't cause the PC to completely lock up... at least not that quickly. For a PC to lock up that fast after booting it up, the CPU would have to have almost no active cooling at all.

I'm at a loss right now. You'll just have to fish around inside the chasiss and see if something is loose, hot, whatever. Sorry. 🙁

 

[Anouar1710]

THanks a lot 😊