Optiplex 3040 Documentation  The link was edited, originally was for the 5070.  Subject lines don't carry over in posts anymore making it easier to remember what we're working with. Just so you know and to save on any confusion, your 3040 is a micro and not an SFF.  SFF's are little bigger.  Also for future reference, no posting service tags.  They aren't public info. There are no manual settings in BIOS to tell the power switch lights what to do.  There is the possibility it burned out (rare), but could've been on all of the time.  Another possibility is that it was never working. Default settings in BIOS are fine as long as Secure Boot is on.  It enables the machine to protect itself while software is still loading. [IMAGE]  
i) Can anybody kindly explain the functionality of the LED within the power switch/button on this micro 3040 (Tag Number ).  I've just acquired this used but working example with a 2.5GHz Intel I5 and 8Gbytes of RAM, 256G SSD.  At first I thought the machine wasn't working as the power switch fails to illuminate with a solid white light as my 5050 and other Dells I own do. However the machine works and runs Windows as expected. I've just run the built in diagnostics (F12) and all seems well. Why this odd behaviour ? It this the intended mode? (I've seen a brief amber flash but that's all).   I'm an Engineer so pretty fussy , hope it's not a silly on my part but it could be!  ii) I did also note on arrival that the machine that the centre pin on the DC jack plug is very deep in the body of the plug. At first I thought perhaps it had been broken but as the computer is working I guess not ? Couldn't find a spec of the the connector any where. [URL] Thanks in advance for any support.
Power On Switch on my Micro 3040 SFF (small form facor) computer not 
illuminated White