Raspberry Pi: Why Won’t My Monitor Work??

New toys are exciting.  Every moment not spent unpackaging and getting your toy ready for action is a moment wasted.  That’s exactly how I felt when I got my hands on my first Raspberry Pi.  Initial State’s ever-generous leader had provided me with everything I needed to get started – an HDMI monitor, a Bluetooth keyboard and mouse…life was looking pretty good.
raspberry pi, wood, single board computer
I made sure everything was hooked up properly, turned on my monitor and then powered up the Pi.  And…nothing happened.  Instead of the beautiful Raspberry SVG popping up on my screen, I saw a “No HDMI Input Detected” message.  I was confused.  I checked the HDMI cable.  I checked that the Pi was actually on.  Everything was good.  But everything was not good because the most important slice of my Pi was refusing to cooperate.
Come to find out, Initial State’s leader wasn’t overly generous – the monitor was probably as old as HDMI itself.  And after a bit of research, I realized that Pi’s tend to have widespread issues not working with older monitors. But I’m an engineer, and I wasn’t going to let that stop me.  When rebooting failed, I turned to Google and found out about a very important config.txt file that was the answer to my problems.
Problem #1:
The monitor is not working with the Raspberry Pi
Fix:
Change the config.txt file
raspberry pi won't show on hdmi monitor, hdmi trouble, monitor trouble, connect board to monitor
Problem #2:
NOOBS, Raspberry Pi’s out-of-box software that came preloaded on my SD card
The problem with NOOBS is that, while it does have lines in it’s code to help your monitor recognize the Pi’s HDMI signal, the key presses (1 for HDMI preferred mode and 2 for HDMI safe mode) never worked for me.  And since I couldn’t see the NOOBS interface since my monitor wasn’t working I couldn’t access the config.txt file that way.
Fix:
I decided that the OS I wanted was Raspbian.  So I went and downloaded just Raspbian (this will work for any other OS too).  When I unzipped the file, I now had access to the config.txt file!  If you open it up, you’ll see that the entire file is commented out:
# For more options and information see
# http://www.raspberrypi.org/documentation/configuration/config-txt.md
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
#disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
#hdmi_group=1
#hdmi_mode=1

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800
I went through and uncommented these lines to cover all of my bases:
# uncomment if you get no picture on HDMI for a default "safe" mode
hdmi_safe=1
# uncomment if hdmi display is not detected and composite is being output
hdmi_force_hotplug=1
# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
config_hdmi_boost=4
Result:
The new uncommented lines worked like a charm.  My monitor recognized the Pi as soon as I booted with the newly formatted SD card.
Now you can play with your new toy!  If you’re looking for a good starter project, check out my post on using buttons to turn LEDs on and off!

23 comments On Raspberry Pi: Why Won’t My Monitor Work??

  • 3 days of hunting and this post finally got me through. My poor son has been anxiously trying to use his Pi to no avail. Great post and so happy that his first experience started with hacking his computer 😉

  • Darn, this only got me part way. I can now see boot messages and the raspy logo on the topleft. Now I am kernel panicking. Even ran fsck against the partition that was getting dinged. Still no love.

    • Uh-oh. I’m not sure what could be messed up. Maybe you should just try reformatting your SD card and reinstalling Raspbian if you can’t find any other resources on the problem.

  • Thanks! I finally got my Raspberry PI to work with my 32″ HDTV. This got my 8 year old excited about seeing the machine boot up on a big TV. Of course the occupational hazard is now she can play mine craft on a big screen TV. I was able to get her off the game long enough to learn how to write her own ‘Hello World!” program in python.

    • hi plz help me to set screen resolution for my 32 inch tv i installed android 7.0 os but i have problem offscreen in top,right,bottom and black border in left side plz help me

      # For more options and information see
      # http://www.raspberrypi.org/documentation/configuration/config-txt.md
      # Some settings may impact device functionality. See link above for details

      # uncomment if you get no picture on HDMI for a default “safe” mode
      #hdmi_safe=1

      # uncomment this if your display has a black border of unused pixels visible
      # and your display can output without overscan
      disable_overscan=1

      # uncomment the following to adjust overscan. Use positive numbers if console
      # goes off screen, and negative if there is too much border
      overscan_left=-16
      overscan_right=16
      overscan_top=50
      overscan_bottom=50

      # uncomment to force a console size. By default it will be display’s size minus
      # overscan.
      #framebuffer_width=1280
      #framebuffer_height=720

      # uncomment if hdmi display is not detected and composite is being output
      #hdmi_force_hotplug=1

      # uncomment to force a specific HDMI mode (this will force VGA)
      #hdmi_group=1
      #hdmi_mode=1

      # uncomment to force a HDMI mode rather than DVI. This can make audio work in
      # DMT (computer monitor) modes
      #hdmi_drive=2

      # uncomment to increase signal to HDMI, if you have interference, blanking, or
      # no display
      config_hdmi_boost=4

      # uncomment for composite PAL
      sdtv_mode=2

      #uncomment to overclock the arm. 700 MHz is the default.
      #arm_freq=800

      kernel=zImage
      device_tree=bcm2710-rpi-3-b.dtb
      dtparam=audio=on
      dtoverlay=vc4-kms-v3d,cma-256
      initramfs ramdisk.img 0x01f00000
      mask_gpu_interrupt0=0x400
      avoid_warnings=2
      gpu_mem=256
      enable_uart=1

  • Where can we find the config file? Also can you provid the link for Raspbian OS? I can only find the image – “2015-05-05-raspbian-wheezy.img” in raspberri pi website.

    • You can find the config file by entering “sudo nano /boot/config.txt” into the terminal. Raspbian wheezy is the correct OS! It is a distribution of Raspbian.

  • I have the same problem (monitor will not recognize the pi), however I tried exactly what you’ve done here and it hasn’t worked. I confirmed that the HDMI port works when I hooked up the Pi to the same monitor when NOOBS was still on the SD card. Frustrating, any other suggestions?

  • I don’t normally comment on things but this post was amazing. Thank you so much.

  • Is this methotod works for NOOBS v1.9.0 .Cound not filnd confic.txt

  • Works like charm. Thank you 🙂

  • I have been up and down the Internet and many different blogs and I still can’t get my HDMI to work. PLEASE…. help. I got Raspberry PI 2 Model B.

  • HDMI_SAFE

    Setting this to 1 uses “safe mode” settings to try to boot with maximum HDMI compatibility.
    This is the same as setting the following parameters:

    hdmi_force_hotplug=1
    hdmi_ignore_edid=0xa5000080
    config_hdmi_boost=4
    hdmi_group=2
    hdmi_mode=4
    disable_overscan=0
    overscan_left=24
    overscan_right=24
    overscan_top=24
    overscan_bottom=24

    reference: ” https://www.raspberrypi.org/documentation/configuration/config-txt.md

  • How do you boot if you don’t want to lose all your files?

  • A website does not comprise or include SSL-certificate, does not imply that this web site is unsafe, but the low security degree.

  • You are a life saver. I bought a monitor (new) and such and couldn’t get anything to work, and the SD card was fried. I got a new SD card and still nothing. You saved the day.

  • Thanks for great blog post! Helped me out also!

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