Dell gx280 Optiplex No Power - Tried New Power Supply

[Josie99]

I am working on a Dell gx280 mini tower. I don't know the exact details of the 'power loss' but apparently the fan started making a noise like a 'hair dryer' and then the computer would not stay running. Eventually the computer would not start at all - another person tried putting a new motherboard in the unit and that appeared dead when it arrived - he couldn't get it going again so he returned it to the owner - that's when I got involved. I have had experience with around 150 of these models (in my job) and I found that the power supplies were lousy - probably had to replace about half of the power supplies because they 'died' in the manner described above so I got a new power supply and voila nothing happens - still no power but the aux power light on the motherboard. Any ideas of what to do next?

[willcomp]

The components which must be operable for a PC to power on are the PSU, motherboard, and CPU. It will usually power on with a faulty CPU unless electrical continuity through the CPU is lost. Barring a catastropic CPU failure, motherboard and PSU are left.

I recommend removing motherboard (with CPU and memory left installed) and testing on benchtop. Place mobo on cardboard or shipping foam, connect PSU and start using a jumper to short power switch pins.

Try using jumper to start PC before removing mobo from case to test for a faulty power switch.

[Josie99]

I am assuming that the PSU is the Power Supply Unit? Thanks for answering - we will try these suggestions.

[willcomp]

You assume correctly :-)

[bobdowding07]

There is an issue with the GX 270 and 280 motherboards.They have capacitor issues.They bulge and rupture. If you didn't get it replaced by Dell by the Jan 31st 2008 deadline you are stuck.There is a website called Badcaps.com that sells the kit to replace the caps.Just Google GX 270 and there is page after page on it.