XPS 8920, power up problem

Any beeps at all or a flashing light? Try pulling the memory and see if you get beeping. If so then the motherboard and BIOS would appear to be able to detect a no RAM error. Try the RAM one module at a time in the DIMM slots. If that module makes no difference as you move it from slot to slot, then try the other RAM module. Also try replacing the CMOS (coin cell) battery. Hard to believe it is bad but it is possible. If that does not help, then unplug the power cables to the hard drive, optical drive, etc., and pull the video card and any other expansion cards. So that only the motherboard has power connected internally. If the system responds, then connect the hardware one at a time then reboot after each connection until the system no longer boots. When it fails to boot, the last piece of hardware you connected should be the problem. The second link should point you in the right direction.

https://www.dell.com/support/manuals/us/en/19/xps-8920-desktop/xps-8920-service%20manual/procedure?guid=guid-2d8bb1f3-d937-47ad-bdf6-60ba81bcfb8d&lang=en-us

https://www.dell.com/support/article/us/en/19/sln153751/no-post-no-power-no-video-on-a-dell-desktop-computer?lang=en

I have a issue same as this, but a workaround is to hold the PSU test button on the back, then press the power button. Like a jump start. I have replaced the power supply and still have the same issue. It could be a motherboard problem.

gloverltd,

Much confusion here. You replied to a thread from February for the older generation XPS 8920. Yet, the service tag number you provided is for the XPS 8930? So are you trying to help Peter622 with his XPS 8920 or are you seeking help with your XPS 8930?

most times , power on then off in 2 seconds (couple) is not overheating,even if the heat sink falls off in shipping

it will run for 30 seconds, I bet, not overheat in 2 seconds flat, (I'm keying off stated OP facts , only)

BIOS never loads or works.

no beeps or flashing LED codes.

just fans up then down in 2 seconds.

do the long hard reset first, (Ive seen vast PCs the ICH chip (power controller mess up)

cures 3 things,

close by lightening hits.

and you  doing ESD events.

and 3,  stuck in sleep mode or stuck on hibernate mode or there sisters.

do this simple thing first.

http://www.pcdied.com/PSU/hard-resets.html

The PSU  is  bad or  the MOBO (motherboard) and all friends connected are shorted.

lacking good spare PSU (a wise idea)

then strip the PC down

the PSU on all PCs shut down with there is a RAIL overload. by DESIGN

385watt PSU it is.with  real (almost) ATX type power cables (lots) not just 4/6 class

the PSU button is power on override, (only proves 1 thing the Power on pin on the PSU works but  not your PCs mother board, same.  and is not any kind of real test on any PSU. (PART OF YES)

the motherboard can also (yes shorts on VRM of Mobo) can shut the PC off lightening fast. 1sec or far less.

STRIP IT DOWN. GET RID  of all power loads, (learn that any module can short, ok? it's a fact of life)

1: all SATA power cables

2: all PCI cards. next.

3: all USB not needed , removed. first. not 3rd in my list sorry.

4: pull all ram and test them 1 at a time,

5: http://www.pcdied.com/PSU/strip-down-testing101.html

Green Light on the back DOES NOT indicate that the power supply is OK.

All it means is that 120VAC is coming into the box.

Shutting down can also be a sign that cpu is overheating.

Non Dell Power supply like EVGA 700BR works fine in

Studio XPS 435T / 9000
Studio XPS 7100
Studio XPS 8000
Studio XPS 8100
Studio XPS 9100

XPS 8300
XPS 8500
XPS 8700
XPS 8900
XPS 8910
XPS 8920
XPS 8930

https://www.bestbuy.com/site/evga-700w-atx12v-eps12v-80-plus-bronze-power-supply-dc-dc-technology-black/6346160.p?skuId=6346160

Did your problem end up being a mother board issue, something else, or do you continue the front and back power button start method?  I am doing the same which works for now.  I did replace the start button LED switch witch offered no change.  Thank you.