27 All-in-One EC27250, both HDMI connection not working

Question

I have two extra dell monitors that I want to connect to my dell all in 1 desktop. So, I would have 3 screens in total. Only one HDMI connection is working. I have switched around the connections to make sure it was not the monitors. Out of the two HDMI on the desktop. Only one is working. I have returned the first desktop and received a new and this is the same issue I am running into. Can someone help on how to use 2 extra monitor on this desktop

redxps630 · Accepted Answer

Dell AIO when the model has two HDMI ports at back, only one is for video out to a second monitor, which is labeled HDMI-out in manual. The other hdmi port is for sending video signal into AIO display when you use it as a passive monitor and not a pc. That is labeled as HDMI-in. If you connect that port to an external monitor, nothing happens as both were expecting input only.

therefore it would never support two hdmi external monitors.

carolineharper · Answer

I had the same issue on my desktop before. One HDMI port was not being detected at all. I updated the graphics drivers and restarted the system. After that, I opened the display settings and manually enabled the second monitor. That fixed the problem for me.
I hope this also works for you.

carolineharper · Answer

@redxps630​ Yes, I tested the HDMI cable and monitor on another system and they work fine. I have also updated the BIOS and graphics drivers. The issue still happens on this desktop, so it may be a hardware-related problem with the HDMI port.

redxps630 · Answer

Dell does not make All in one desktop that has dual HDMI-out ports. That is not industry standard for AIO.

If you want three display, get a regular Dell desktop, not an All in one.

Example of Dell All in one spec: HDMI-out 1.4b, HDMI-in 1.4b

DELL-ChrisM2 · Answer

Adding some clarification and edit of thread title. This thread was about the 27 All-in-One EC27250. The online 27 All-in-One EC27250 Owner's Manual page 10 shows the difference of the HDMI ports =

Brandon246 · Answer

@redxps630​ please help I have a dell all in once ec2750 that stopped going into hdmi mode last time i was able to work on it was jan 10th 2026 its brand new never had a problem cables are fine everything has been plugging in correctly help at this point im having issues

Brandon246 · Answer

@redxps630​  monday the 12th i was not able to swtich with button to hdmi in mode to this day i cant get anything to go hdmi

redxps630 · Answer

If the button to switch to hdmi IN mode suddenly stops working you should call Dell for warranty repair

Display Built-in Self Test button/Input-source selection button

This button has two functions:

● When the computer is on, use this button to select the video input-source.

Press the button to switch the display between the internal system display and HDMI input.

Dell Pro Desktops

27 All-in-One EC27250, both HDMI connection not working

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