XPS 2720 all in one

Does the fan speed up before it shuts down?

84° C is pretty hot and may exceed limits.  If it is getting that hot, possibly the heat removing process is failing in some manner.

There are times with Win 10 where the system is used quite heavily.  Possibly getting ready for a Windows Update or a McAfee scan.  On one of my system I had to remove McAfee because it was writing to a drive using 100% drive capacity to a log file.  The fact this situations may not happen at specific times might explain why your system has problems when the diagnostic is not being performed.

thankyou for the reply... Thats a good question if the fan speed up before it shutdown due to my deafness.. so I was not able to hear. maybe I should ask someone to hear it for me if that helps you to narrow down the problem..

Dell originally said I had a bad motherboard that cause the shutdown/restart. So I ordered a used motherboard at a reasonable price.. I had a local repairman trying to install a new motherboard to see if it would resolve this issue.. But it turns out he couldn't remove the last two wires (I assume screws) of the motherboard.. He said that it is glued down to the socket and he did not want to damage the motherboard by pulling out so hard.. so he never had the chance to install a new motherboard.  He tried to use a new thermal paste on heat sink.. That didnt help.. Maybe it helps alittle bit on the normal use.. In the past it shutdown every 2 weeks but now its doing every 3 weeks or more.. but it continues to shutdown when doing the diagnostic testing EACH TIME.  Diagnostic testing is done by pressing F12 if you know what I mean

Now this local repairman seems to think its the power supply???  I dont want to replace power supply until I do a complete research.. Did you think its software related?? thank you

Thank you for letting me know about the motherboard. I dont know if Tech is aware of this . maybe its a good thing he didnt replace the motherboard because he seems to think my existing motherboard is still in a good shape

When I get home from work. I will feel the air on top of the Center of the Monitor.. If I remember correctly, I think the center of the monitor  is our webcam.. Im assuming theres a vent fan next to the webcam.

Yes I did receive a blue screen but for a very very short time since I downloaded DELL updated driver and then the blue screen went away right way so It appears this blue screen is unrelated to the problem I am having right now with the shutdown. The blue error message I had was  WHAT FAILED: iaStorAV.sys .. I no longer have this anymore.

Yes I did check event viewer. It says my SSD failure. But when I ran Seatools by seagate which tests for all of the hard drive.. and it passed.. Puzzling why diagnostic testing failed on SSD while Seatools passed my hard drive.. But currently when I did the diagnostic testing, now my SSD passed.. so diagnostic testing are giving me different answer..  The last time the timestamp  showed SSD failure is Juyl 18 and Aug 5th.. but it has passed lately

you are Right, the diagnostic do not finish so no report is made. But at one time. it did pass all of them.. It just happen once while the rest would shutdown. So I dont know if diagnostic testing is reliable these days??

I have not seen device manager, I will check when I get home from work tonight

Yes the temp is showing in C....  Im seeing the tempature in diagnostic testing under CPU thermistor or something like this

Yes running Win 10... It came with Win 8  but was upgraded to Win 10 last fall

yes I unplug all of my USB and any external devices while running the diagnostic testing

The Motherboard sticks because the Nvidia GPU is on the back side of the board in a heat sink material, assuming it is like mine which is a little over two years old.  The service documents on the Dell site are very helpful if you need to open the system.

If you can't hear the fan, you should be able to feel the air coming out the top near the center.

Are you getting any Blue Screen Messages or have you checked for a Memory Dump file or a Minidump folder with files there?

If you look at the Event Viewer, are you seeing any consistent errors or warnings which might lead to the problem?  In many cases, errors or warnings regarding power problems may happen because of the unexpected shutdown.

I assume the diagnostics do not finish so no report is made?  Can you run the diagnostics on one component at a time?

In Device Manager, do you see any yellow triangles or unknown devices?  Is the Video adapter section showing the Intel and Nvidia GPUs?

The temperature you are showing is Centigrade and not Fahrenheit?  Where are you seeing the temperature?

Try testing by turning off anything you can do without, even in the Bios.  Then unplug external devices.

Are you running Win 10 on that system?

I just send you a message. I forgot to add.. Yes it can  run the diagnostic on one component at a time.. Most of them have passed all the time except for SSD, memory where it sometimes shutdown.. but at other time, it would pass the SSD and memory if the temp is not too high

You won't know for sure until it comes on.  If you have McAfee, run a Virus scan which will probably turn it on.  Run it with the back off as long as possible.  If the system is really getting as hot as you think, it will diminish the life of the processor, and maybe the display.

I sent you a message at 18:56 and 19:01.....I forgot to mention this to you. When I remove the cover, the temp is good  I think around 68 or less ..... It probably wont shutdown when the back cover is removed since the temp stays low...  does this tell us that our fan is not working properly???  

I just checked Setup Assistant for my processor core temps and they are sitting around 50° C.  It will of course vary depending on the ambient temp in the room and mine is around 78 degrees.

I am running a Windows Defender full scan and I can feel hot air coming out the top of the unit but so far the processor is still showing 51 degrees C. 

I don't see the message yet but the air will exhaust from the top, behind the slide button for the camera cover.  

If you can't tell if the fan is running when it is warm enough, you might take the back off and run it that way for a while so you can tell.  Of course, don't touch anything with it running and have it sitting so you can easily see the back.  Only do this if you feel comfortable doing so.

Having the back off will allow more air to enter the system and even an external fan may help.  But if you determine the fan is not operating when it should be you might want to test and replace it.  The system is enclosed so not much gets in on its own.

Follow the directions, and of course unplug the unit before you do anything with it.

For performance issues I like to watch the Task Manager and see if the processor or drive is working hard.  

Everything you are saying points to the System getting hot so I will see if that proves out to be the case.  A very warm system can cause all kinds of problems with a system.

You can also open a Run box, Winkey+R and type: perfmon /rel   to get a graph which can show problem areas on the system.

No, I was wrong about the temps.  I had to rescan with Support Assistant and I can hear the fan running and the temps are now 74 degrees C while running the full scan with Windows Defender.

AND there is no shutdown while the back cover is removed

Is it possible the fan is weak and it is not doing the job with the back cover??

I have removed the back cover successfully.. And I ran the diagnostic testing and I ran on CPU and Memory only... both passed... (in the past< it would failed and rise to 84C with the cover)  Without the back cover,  temp at 68C and it passed... so now the diagnostic testing will pass without the cover.. Hope this will give you a better idea whats the problem?  No I don't have Mcafee   but I think the memory always turn the fan on for me...  Yes the fan was running when testing memory.. In fact, it is still running now while I'm talking to you now... Are they suppose to stop when it cools down??  

My fan stays pretty quiet during normal use.  When doing the Widows Defender Full scan, the fan was modulating through different speeds trying to maintain the 71 degrees C.

Does yours sit around 51 degrees C when not using it?

It is up to you to determine if the fan is the problem.  It could still be something like the heatsink compound on the processor but I think you stated you had replaced that.  It may take a couple of days for it to take effect.

If you can see an air channel you might check for obstructions.  I have no problem being able to tell if my fan is running just by feeling the airflow above and slightly behind..

Basically, if the system gets up to 85 degrees C with the back on, I would say you have a cooling problem..

If it is a cooling problem, which possible components need replaced??? any idea??

The fan is still running as we speak. The temp is now 49C when not using it. Yes Technican did the thermal paste twice. First one with Dell paste. Second one was the other brand which is little better. The paste was done way past couple of days. Yes this system will go back to 84 with cover on..