XPS 8900, runs only after pushing BIST button

try replace cmos battery w a new one then clear cmos settings via mobo jumper 

It would be helpful to know the specific XPS Desktops model?

Hi Chris,

It's an XPS 8900...  But there has been an interesting development...

As you may have seen, it was suggested that things might improve with a new CMOS Battery, and I just put a new one in.

But now, pushing the the BIST button shows Green, but does not start the system. Now, after the BIST test, the power button flashes, but does nothing when pushed.

I will add that I have not, at this point, tried the suggestion that after installing the new battery, I "clear cmos settings via mobo jumper."

Thanks for your thoughts,

Lothar

the fact new battery made a difference confirms cmos settings was corrupted due to a low old battery.  clear cmos has a good chance to solve the issue.

XPS 8900 Service Manual | Dell US

@redxps630​ 

Hi,

I followed your jumper suggestion, but with no benefit. Everything remains, as I described. Might you suggest a next step?

Many thanks,

Lothar

unplug power cord, press power button for 15 sec to drain all flea power.

try remove cmos battery for 10 min then reseat it.

then try clear cmos jumper one more time

Hello again,

Of course, this may be of diagnostic value, but it felt as if we are going backwards...

I followed your steps above, and now neither the power button, nor the BIST button do anything at all. Neither of them displays any sign of life when power is connected, and the buttons are pushed.

Thanks for any further suggestions,

Lothar

it is time to do a BIST of psu

https://www.dell.com/support/kbdoc/en-us/000125185/how-to-troubleshoot-the-power-supply-unit-psu-of-a-dell-desktop-computer#:~:text=Press%20the%20BIST%20button%20on,if%20the%20LED%20lights%20up.

Hi again,

The articles you suggested just above offered information that changed nothing...

Then, as I continued to read, I came upon some suggestions relating to the possibility that one, or both, of my RAM cards was in trouble. I did some testing, and they both appear to be fine.

But it seems that pulling 'em out, and pushing 'em in has changed the status:

Now, when I power up, and touch the PSU BIST button, its led shows solid green, and stays lit long after I release the button. lso, both fans in the box run, and the led on the system's cat5 cable lights.

In addition, the led in the box's Power Button comes on Gold as a triple pattern of ON-ON-ON, Pause ON-ON-ON Pause, etc. If I push the Button nothing seems to happen. But, if I push, and hold the button for several seconds the led on the button displays an extremely rapid double pattern of ON-ON Pause ON-ON Pause, etc. If I then release the button, all the leds turn off, as do the fans.

I am eager to learn if this brings further suggestions.

Many thanks,

Lothar

power button amber code

install only one ram stick, remove the rest, test each ram stick individually this way

if you did not seat the ram properly it would give the error of no memory detected

if one memory stick is bad it may give same error

Re: touch the PSU BIST button, its led shows solid green, and stays lit long after I release the button. lso, both fans in the box run

psu has passed BIST.  it has no issue.

your goal is to accomplish solid white led on the power button which is the only normal sign.

all the rest power button led code implies a problem.