OptiPlex 5040 SFF video is flickering/ blanking (update!)

I'm seeing this this precise problem with Optiplex 5040 systems with HDMI and 2xDisplayPort connections on board. I'm using Acer monitors, very inexpensive no-frills model V246HQL; not sure that matters.

Symptom: system works OK with a single monitor, via HDMI or DisplayPort to HDMI. System will not cold boot with 2 monitors connected if the monitors are HDMI and powered on. Turning one monitor off lets the system boot OK. Switching to a DisplayPort to VGA adapter works around it; and using an HDMI/DVI adapter plug also works around it.

Notable: this was after BIOS upgrade to 1.5.7, and 1.5.9. This was working on BIOS 1.2.7... I should have left it.

Onboard ePSA diagnostics will hang at "Video Card" test if 2 monitors are connected.

My workaround: use DisplayPort to VGA adapters, and connect 2 monitors via VGA.

A motherboard swap fixed this on one system. I'm about to have the second system repaired too under warranty.

I think this might have something to do with HDMI and DisplayPort display handshaking. I'm betting a future BIOS update might finally resolve it.

thanks for the reply. its been driving me crazy. it does point to a bios issue in your case (dell mistake) and my systems are up to date with the latest BIOS (because I am stupid enough to believe that updates are SUPPOSED TO FIX ). Dell, can you please look into this? PS, on a side note, my personal system did this today. sigh :|

good talk Dell

Worst...support...EVER.

dang it dell-- you have any ideas?  mine just started doing this again out of the blue

it goes blank, makes the "ding-dink" like something got unplugged, then the screens come back on and it makes the sound like a device was plugged back in

HALP!!!!!!!!!!!!!!!!!!!!!

I see there are four other threads/posts with similar problems

dell can just replace all the motherboards in our hundreds of 5040's...im out....

There  is something not quite right about the 5040 onboard display. I see machines occasionally just refuse to display anything, no output at bios etc. Only thing that cures it for me so far is shutdown entirely and remove power, then. drain power. by pressing power switch for anything residual in capacitors.

Then plug everything back into the mains and it's ok again. I'm hoping a bios upgrade will solve this but just thought I'd share my experience as were only using single screens via the display port output.

we opted for MB/replacement and getting GOOD video cards.  DELL was less then zero help in this.

bad for them...we are now looking at other companies for our main PC line.

still have this issue

seems if you have a DELL (yes DELL) 24" monitor, you get this awesome blanking.

pure garbage.

as usual. ZERO help from dell.

we have these happening all over the place now....

looks like the dells 5040/7040 sff are susceptible to radio interference (I kinda thought they test for that stuff....)

seems all the computer doing this have walkie-talkies near em....like deputy wearing his 800 mhz radio...

looks like they have a shielding (lack of) issue with these models

Since I have tried every conceivable monitor cable combo possible, I don't thin kits the monitor cables

if that signal is getting "in" to the dells/monitors...what's getting out...

also-  lookslike plugging in a phone (iphone in my case) to yhe usb on front makes the computer blank in and out.

common dell-- what is your fix?

Dell...

Bueler

Bueler....

just thought dell would want to know their systems cant handle a phone getting plugged into them

guess they don't care,