9020, black screen, no bios

Right, strip it down as bare as possible.

If PowerSupply checks good with digital-tester, I would say bad motherboard.

https://www.dell.com/community/Alienware-General-Read-Only/Alienware-Desktop-General-Hardware-Troubleshooting/m-p/5555517#M57436

Fixing computers isn't always easy. You won't know the exact problem until it's fixed (if you decide to go that far).

Just ran into this issue myself! Unplug and remove the following from the computer; all hard drive(s), cd rom, video card, external usb devices (except keyboard/mouse) and RAM. Use the built in video card to your display, if you're already utilizing that then you're good. Leave one Ram stick in slot 2. Boot her up and it should give you the option to go into Bios. 

Have you checked to see if the mobo isn't fried? If it isn't and if it's giving beeping error then the steps I listed should take you to the Bios. Connect your computer via it's built in VGA to your monitor. Leave one memory stick in slot 2. Reboot your computer and it should give you the option to boot into Bios. Again, make sure every thing else is disconnected. You only want the monitor/mouse/keyboard/memory stick in slot 2 connected.

I cannot tell which one is second slot in this AIO computer. Is it the upper or lower one? I have disconnected the cd drive and the hard drive. There isn't anything else for me to disconnect from the mobo. I've even swapped out the psu with a working computer to rule out a faulty psu not providing enough power. I've swapped out the RAM and still no splash screen or bios.

I have done that and the screen doesn't take me to the bios or anything. 

Hi Tim -

Just curious if you have found a solution yet.  I am experiencing the same issue like you.

A bump to an old thread as I had the same issue and could not find a solution anywhere!  Here is the solution change the monitor, I was using a TV and the bios screen was black, switched over to a VGA monitor and presto the bios screen appears and was able to configure the bios!

@Woody Thank you so much for your comment! I was pulling my hair out trying to figure out what the problem was. I saw your comment and decided I’d give an old monitor I had laying around a shot. Lo and behold, I could finally see the BIOS!!

I had a 9030 aio go black screen of death on me 

The following worked.

Unplug everything and the power a few times. Hit the discharge button on the back a few times and hold for a few seconds. Then turn on the machine while nothing is plugged in other than power.  You will get a keyboard message but after that you can plug everything back in and be good to go

Just a side note, this will reset all the bios setting back to default so make sure you log in and set the date, time and all other settings that you may need to get it working correctly for your environment.

Working on a 9020 with no video.  Not on the LCD display, HDMI or VGA.  Replaced PSU with same results. I was ready to scrap it and remove anything of value and then I removed the CMOS on board 2032 battery and shorted the battery connectors (do this with the power NOT connected).  I installed the existing battery and all video came back.  I will be replacing the 2032 on-board battery before putting it back together and giving it back to the user.

Hope this helps.

Smart move replacing the battery.  It can often be the first thing to check.  A bad battery will cause seemingly unrelated bizarre problems and even throw incorrect error codes.

Reanimating old topic - but seems to not be limited to just 9020, as I've got the same issue with 7040SFF.

A few days back, a black screen welcomed me when resuming from S3. It happened a few times before, and long-press-power-off used to fix it - but not this time. On next start same black screen, spinning fans, no disk activity or anything (apart from on-board LAN getting link light up).

Started removing components, stripping it to barebone - no luck, same thing on every startup. Clearing the CMOS with jumper cap as per How to Perform a BIOS or CMOS Reset, only that I had to press the button on the back of the power supply, that seems to start spinning all fans - just plugging the power back in didn't do the trick. After that, replacing the jumper cap and plugging power back in, I got the desktop to start (the usual self-check quick cycle), then shut down. Then it almost immediately started back again, did nothing (apparently) for about a minute and shut down. Then it started for the third time, showing me the Dell logo and warning that system clock isn't set - offering three options (Retry boot, run BIOS setup, Run diagnostics).

First two options send the machine back to bricked state, never starting up again (until the whole procedure above is repeated). Trying the diag restarts the machine and it boots into Windows. But trying to shut it down or restart from within Windows bricks it again.

So, while technically I can get the machine working, I suspect it won't be long before it permanently fails. Wet finger assessment, something's wrong with BIOS power management - or a botched firmware. Not risking shutting the machine down to reflash BIOS as I need it for work, but will try that later and see what comes out.

Did you ever get this working? I have the same problem. Removing a stick of RAM or resetting CMOS throws an error “RAM configuration changed” or “system time not set” and allows me into the BIOS, but the next boot is a black screen with no boot to the OS.