Optiplex GX280 wont boot

on the back above the USB ports there should be diag L.E.D.s. What colors are they?

They are not lighting up at all.

ok, i assume the power button isnt sticking, so I would recommend just having Cpu, RAM, and a video port hooked up and try again. Unplug all drives, usb devices, etc...  Also, you can check the capacitors close to the CPU heatsink on the motherboard and look for signs of leaking, swelling,bulging etc...  For the hay of it you can clear the cmos also. < ADMIN NOTE: Broken link has been removed from this post by Dell>

or here ya go:

Clearing the NVRAM for the; 330, 755, 745c, 745, 740, GX620, GX520, GX280, SX280

By Jumper:

Turn off the computer and disconnect the power cable from the electrical outlet.
Remove the computer cover.
Reset the current CMOS settings:
Locate the password (PSWD) and CMOS (RTC_RST) jumpers on the system board.
Remove the jumper plug from the PSWD jumper pins.
Place the password jumper plug on the RTC_RST pins and wait approximately 5 seconds.
Remove the jumper plug from the RTC_RST pins and place it back on the password pins.
Close the computer cover.
Attach the computer stand, if used.
Connect your computer and devices to electrical outlets and turn them on.

 

is this a Small Mini Tower?  Desktop?

OK... Disconnected HDD, Optical Drive, & Floppy.  Same symptom

Removed all memory modules... Same symptom

Removed green pswd jumper & booted... Same symptom

Removed CMOS battery & booted... Same symptom

Replaced jumper & CMOS battery & rebooted... Same symptom

Reinstalled memory in DIMM 1 & DIMM 2 slots.....Same symptom

ok. I would have to say its either PSU or MoBo.  Any chance you have a spare Power Supply to try?

 

Did you happen to look at the capacitors??

 

If you want, you can check PSU voltages also too.

following these:

http://support.dell.com/support/edocs/systems/opgx280/en/ug/pwrsply0.htm#wp1112517

 

I removed the fan to get a better look at the capacitors (There are 9 of them lined up behind the cpu) and didn't notice any bulging, leaking. or discoloration.

 

I connected a spare psu & restarted....same behavior.

 

So, I guess MoBo, huh?

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ccribb wrote:

I removed the fan to get a better look at the capacitors (There are 9 of them lined up behind the cpu) and didn't notice any bulging, leaking. or discoloration.

 

I connected a spare psu & restarted....same behavior.

 

So, I guess MoBo, huh?

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I would have to agree.  I cant think of anything else that could be shorting it out like that.