This post is intended to help beginners working with Raspberry Pi to get the display output through HDMI output. This post assumes that the user is running Raspian OS in your RPi board.
In most of the cases the HDMI displays will work straight away. For some there will be problem, getting the HDMI display wont work out of the box. The main reason for this behavior is that the display will be output through the RCA jack if the raspberry pi cant see a HDMI monitor connected to it at startup. In some cases, even if the HDMI display is connected the display data will be redirected to the RCA jack instead of the HDMI interface. So we will provide to methods to solve these problems.
Step1: Insert SD card containing Raspbian into your PC/Laptop. You can use either USB Cardreader or inbuilt Laptop Cardreader for this purpose.
Step2: Open the Boot partition of SD card and open the file named config.txt
Step3: Uncomment the lines saying #hdmi_force_hotplug=1 and #hdmi_drive=2 by removing # from the beginning of these lines.
Step4: Eject the SD card and insert it into the RPi. Power it up and your display will be working now.
Method 2: (Advanced Users only)
Step1: Connect a USB to serial converter to RPI.
Step2: Open a terminal emulator software (eg: PuttY) with baudrate 115200.
Step3: Login into the RPi console when asked(Default username: pi, password: raspberry)
Step4: Open the file /boot/config.txt using the command sudo nano /boot/config.txt
Step5: Uncomment the lines saying #hdmi_force_hotplug=1 and #hdmi_drive=2 by removing # from the beginning of these lines.
Step6: Now save the file using Cntrl+O(Writeout) and reboot the Rpi by issuing sudo reboot
In case if you are still not getting the display, then that may the problem of HDMI cable/display.
Changes to be made in /boot/config.txt in a glance
# Force the monitor to HDMI mode so that sound will be sent over HDMI cable hdmi_drive=2 # Set monitor mode to DMT hdmi_group=2 # Set monitor resolution to 1024x768 XGA 60Hz (HDMI_DMT_XGA_60) hdmi_mode=16 # Make display smaller to stop text spilling off the screen overscan_left=20 overscan_right=12 overscan_top=10 overscan_bottom=10