The case of the HDMI output failing after some period of use is somehow related to switching the monitor between two PCs. You might be using the monitor in your work PC, but change it over to the gaming PC. On getting it back to the work PC, nothing displays. There has been no official reason as to why this occurs, but it seems that the monitor gets stuck to some settings that are not compatible with the HDMI output of the PC. High-end monitors usually have more than one input source. Usually, monitors come with the VGA input set as the default input. If you have not changed the input source to HDMI, then you will not get a signal via your HDMI cable and your computer will not detect it enter. This is the most overlooked reason why the HDMI input gets no signal on your monitor. Here is how you can get the monitor working again. This applies to cases where you are using a HDMI to HDMI port connection and not via the mac mDP.
Method 1: Reset the monitor
This method will help for monitors that have developed this issue suddenly. Resetting the monitor really means that we have to get all the stored up electricity to be used up completely. Monitors usually have capacitors that store charge hence, even when unplugged, the electronics might still be powered enough to maintain their last settings. To reset the monitor:
Method 2: Change the monitor input source to HDMI
Monitors with a HDMI input usually have more than one signal source, including VGA, DP and DVI. The VGA input is usually the default input. To set the source to HDMI we will need to change the setting in the monitor menu. If the above methods do not get your input signal back, then you will be better off contacting the support department. This mostly apply to people that never got a signal from their HDMI input after purchase. Dell has acknowledged the HDMI problem with the S2716DG monitor that run on the A00 and A01 revisions. The understanding is that the HDMI bug has been fixed for both PCs and XBOX or Play Station in the A03 revision. You can tell your monitor revision number by checking the box it came in or by checking the sticker behind the monitor at the end of the serial number as shown in the image below.
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