Optiplex power supply problems - known issue?

For reference, there are two other discussions reporting problems with Optiplex 790s:
"Optiplex 790 Flashing Amber Power Light", http://en.community.dell.com/support-forums/desktop/f/3514/t/19423875.aspx
"Issues with Optiplex 790 SFF 240 watt power supplys", http://en.community.dell.com/support-forums/desktop/f/3514/t/19433355.aspx

The first of those discussions was started in November last year, and in it a couple of users reported a crackling sound and electrical smell.  I just heard (indirectly) from one of my users that the computer smelled like something was burning.  I am beginning to wonder if this is a safety issue.

We have also experienced this same issue with the Optiplex 790 SFF. We are running dual video with Radeon 512MB HD 6350 low profile. So far there are 6 reported failed machines - mostly with the amber flashing light. Sometimes due to failure, the HDD gets corrupted causing a blue screen. I am working with our account team at Dell to find a resolution. I am seeing posts where users have indicated an airflow issue with the PSU design, but noone is absolutely sure that is the root of the problem. I would suggest to report as much of these issues as you can to your Dell Account Team. FYI - the PSU model that is failing is also H240AS (240 watt).

Additionally, 99% of the machines that have failed so far are the i7 - 2600 configuration. We have one failure on an i3 - 2100 out of ten machines. Both have low profile Radeon 6350.

Hey there,

We've updated about 100 PCs, about 50 of which were 990s.  We've had 5 power supplies fail in the last 3 months.  They're I5-2500.

I also provide support for a large corporation and we have deployed approximately 600 Optiplex 990's over the last 6 months or so.

Currently we are running at a 13% failure rate with an average desktop lifetime of 99 days.

Dell have provided a stock of power supplies but have stopped short of admitting they have a problem.

We purchased 10 of the Dell Optiplex 990 ultra small form factor PC's in December. Since then we have had a 40% failure rate of the power supplies. What gives?

My issue with a Optiplex DESKTOP form factor, purchased in November.  On reboot from Windows update, unit started short cycling.  Turns on for about -3- seconds then shuts off.  This continues unit I pull power cord.  The attorney this happened with upgraded his office (actually I did) with five of these machines that went live mid-December 2011.  Two servers as well.

Thought might have been an update issue with Windows, but since the server (SBS2011 Premium) updates the workstations and no other was acting this way.... >yet<..  So I took a brand new 790 (delivery mid-Feb) and pulled the HD and memory upgrade and swapped them out.  No problem, up and running.

Brought the failed unit back with me and replaced the PS with another 790, also from the November batch I had ordered.  This unit has seen about 10 hours of service.  Used the factory HD with image from the new 790 I took to his office to swap out and no network connection.  All of this yesterday.  System from his office now booted fine and was running.  Good, power supply issue.

Chatted with support and the new PS was overnighted.  Had left the workstation running since yesterday.

FedEx delivers the PS and I go back to the bench and the system is off.  So I hit the power button.  Viola, it starts this power cycle issue, with the PS I installed yesterday.

My questions deals with three things I am looking at but at this point do not think the PS is the issue (have not opened the replacement yet).  So the other two would be:  1) any of the power saving settings from BIOS (A10) as I do not use sleep or hibernate, or 2) motherboard but since the power cycling is so fast (3 seconds or so) I do not trust the LED indicators as they just barely get through the initial all illumination before it does the cycle shutdown and restart?

This YouTube illustrates exactly what is happening but my problem is with the model 790, not 390.

And I tried the new PS hoping it would boot long enough to upgrade the BIOS from A10 to A11 (3/8) but it is still cycling.  And I did pull the coin cell and power to allow the BIOS to default as suggested by other.  No luck.

I have SFF 990 as well an dhave experiened over 40 percent. Oddly enough I have a coupel machines that I am now swapping out the power supply for the  second time.

Hello all, I've been having similar problems with all form factors especially desktop and mini-towers. We have been replacing motherbards and that has resolved 99% of the failures. Very few have been actual power supply issues except for the small form factors.

What is up with the cheap Power Supply's Dell is using in the Optiplex 990 SFF??? We are seeing at least a 40 percent failure rate with them in our company and I'm getting tired of calling support to send out new Power Supplies.  Maybe if Dell made their PC's in the US and used Americans instead of Chinese employees for their testing and development, we could have quality products from Dell like they used to produce before moving all their resources to China and Taiwan. Going to present facts to our Procurement Dept. to convince them to switch to HP.

There is probably nothing wrong with the power supplies, except that a 265 power is just not powerful enough. Running near max output will spell doom on any power supply. You need at least 380 watts to run this type of setup.

3-Opti 790's sff Radion 6350x1-This is what I was told. From this PS manufacturer with Rev.A00, there is a 50% chance the PS will fail. Not sure but think it might be HIPRO because I have received 2 warranty replacements with the same DP/N as the Failed PS's but with rev. A02. The third replacement was a LiteOn with a different DP/N as the failed. Because I'm in a remote area, they sent me a spare replacement to use if another one fails. I just have to exchange it when a warranty replacement arrives and I still keep the spare to use if another PS fails. We also have 8 of the same systems without the Radion 6350 that have not failed yet. Anyone experience a failure without the Rad. 6350's installed?

If you can at least get to the BIOS setup, then try loading a copy of windows 7 from a DVD (it's the only way i could get to the windows desktop to run the BIOS update.) If you don't want to lose any data throw in a temporary drive to install windows 7 on to update the BIOS, then put your original hard drive back in after it's fixed.  Once windows 7 is finished installing and you get to the desktop don't restart, install this (the link below) and it will shutdown and hopefully update the BIOS to version A11. I tried rebooting after windows 7 install, but it wouldn't boot after shutting down. So again once you get to the desktop (right after installation is complete) don't restart, run the BIOS update (the link below) and viola! Mine is starting windows 7 every time (no more auto power cycles.)

(once the bios is finished updating

You should be able to install any OS as normal)

downloads.dell.com/.../O790-A11.exe

The problem seems to be with the AC power auto recovery. I also tried disabling the AC recovery, but no luck. So don't waste your time messing with that.

If you can not get to at least the BIOS then try a different power supply unit and pull out the CMOS battery, and if that doesn't work you will have to swap the motherboard.

Hope this helps. Sorry for the repetitiveness.

**UPDATE**

My machine is still rebooting after a few normal power cycles. :(  

But I can boot fine if I spam f8 at boot up and select start windows normally :) It's a bit of hassle, but its my home machine and I refuse to throw it out! (it was a gift to tinker with since it was "broken") Everything works as normal once booted up!!