If you’re stuck with a Raspberry Pi monitor that’s not working, you’re not alone. If you’re not seeing any HDMI output on your monitor, this guide offers easy-to-implement fixes and troubleshooting tips to help you resolve this common source of frustration and get your external screen back to functioning properly.
Tip: before you dive in, find out your Raspberry Pi version and system information.
Hardware Fixes for Raspberry Pi Monitor Not Working
When you connect a Raspberry Pi to a monitor via HDMI, several aspects could prevent the setup from working properly:
- Your Raspberry Pi’s HDMI port
- Your monitor’s HDMI port
- The HDMI cable itself
- The failure of an adapter, if you’re using one, like an HDMI-to-VGA adapter
- Your Raspberry PI OS configuration
Below, you’ll find a list of suggestions to fix these problems.
1. Check the Cable Connection
The first thing you should check is the HDMI cable connection between the Raspberry Pi and the monitor. Is the cable fully connected on both ends? Is it free of damage? If you suspect the cable is the issue, swap it with a different one and check if the problem persists.
Additionally, to rule out port issues, try connecting other devices with the same cable to see if the display works. If you have a Raspberry Pi 4, which has two HDMI ports, you can try using the other port.
Good to know: This particular model (Raspberry Pi 4) defaults to powering HDMI0 and shuts down HDMI1 if it doesn’t detect a monitor on that port.
2. Check SD Card
Sometimes, the SD card inside the Raspberry Pi can become corrupted, which can cause the operating system to behave erratically or not work at all (this can happen even on new models). If that’s the case with your SD card, the easiest solution is to reflash the card.
To do so, you can use Raspberry Pi Imager to reinstall the Raspberry Pi OS on your memory card. You could also try installing Windows 11 on your Raspberry Pi 4 if you have the latest model.
Once you’ve reflashed the SD card with the Raspberry Pi OS or opted for Windows 11 on a Raspberry Pi 4, make sure the card is securely inserted into the SD card slot of your Raspberry Pi. A partially inserted or loosely connected SD card can lead to boot problems or prevent the operating system from loading correctly.
3. Connect the Monitor First, Then Power On
To establish a successful connection between your Raspberry Pi and monitor, you need to connect the monitor before turning on the Raspberry Pi. This requirement may seem like a significant inconvenience, particularly to those new to using Raspberry Pis, but it’s a standard procedure rather than a glitch.
Good to know: HDMI cables have a “hot plug detect” wire on pin 1, which is the rightmost pin on the wide pin tray. You usually can’t force the Raspberry Pi to work as a “hot-pluggable” device without some software help.
To enable your Raspberry Pi to recognize a monitor connected after it has been powered on – a process often referred to as “hot-plugging” – specific configurations need to be made within the Raspberry Pi’s firmware (see the software fixes section below). The necessity for these settings stems from the way the Raspberry Pi’s hardware, or firmware, initializes display settings before the operating system loads.
4. Use a Shorter Cable
If plugging the cable in before powering up doesn’t work, then it might be an issue with the cable. Typically, the voltage from the Raspberry’s HDMI pins is much higher than the voltage from the other side of the cable. This is called a “voltage drop.”
Where does the voltage go when this happens? Whenever an electron passes through a piece of wire, it tends to leave some heat, so the missing voltage becomes heat energy. For your monitor and Raspberry Pi, that could mean some signals become undetectably faint by the time they get to the other side.
If you want to reduce the electrical energy from being wasted as heat energy, then you should choose a shorter cable – the shorter the cable, the better. If you’re ordering online, you should look for a 30cm HDMI cable. That’s usually the shortest one you’ll find anywhere.
5. Check Your Monitor
What if the problem is the monitor itself? Older monitors may need stronger current from HDMI signals due to wear. Shorter cables may work, but that’s only good if the monitor can listen to weaker signals.
Just how weak of a signal can the Raspberry Pi produce? It largely depends on the model, but a good ballpark could be somewhere far less than 200mA – perhaps even a fourth of it. The Raspberry Pi 4 Model B uses a BAT54XV2T5G diode for its outputs. This diode is limited to 200mA, and the signal gets shared with all outputs, like GPIO, audio, and USB. In contrast, HDMI compliance requirements set a maximum current of 500mA for HDMI signals.
If you have another monitor available, try connecting your Raspberry Pi to it. This step can help you determine whether the issue lies with the original monitor’s ability to receive the HDMI signal.
6. Use the Sources Button on the Remote
This one’s more of a fix for folks using the Raspberry Pi on a TV. Television sets typically default to listening from the antenna port instead of the HDMI port and won’t automatically pick up HDMI output when you plug one in.
To solve this, use the “Sources” button on your remote to change the TV’s input source.
Software Fixes for Raspberry Pi Monitor Not Working
If simple hardware solutions don’t work, then you should try dabbling with the software.
Note: if one of the fixes does not work, revert to the original settings after you’ve tried it. The worst you’d want to happen is having one “fix” cause another problem down the line.
7. Edit config.txt
The “config.txt” file serves a role similar to BIOS settings on traditional computers, allowing you to control low-level system functions and hardware drivers on your Raspberry Pi. Unlike a typical BIOS, which you access during bootup, adjustments to Raspberry Pi settings require direct editing of the “config.txt” file.
Start by removing the SD card and using a card reader or microSD converter to connect it to a different computer. It’s important to avoid selecting the Format disk option if prompted, as this would erase all data on the card, including the Raspberry Pi OS—simply click Cancel instead. Once you have access to the card’s contents, navigate to and open the config.txt file.
Within this file, you’ll need to locate the line #hdmi_safe=1 and uncomment it by deleting the # at the beginning of the line. After making this change, save the file, safely eject the SD card from your computer, then reinsert it into your Raspberry Pi. Finally, connect the HDMI cable and power on your Raspberry Pi to apply the new settings.
If the Raspberry Pi’s monitor still doesn’t work, go back to step #1, and once you reach step #4, look for the following lines instead:
#hdmi_force_hotplug=1#config_hdmi_boost=4
Pick one then continue to step #5. Be sure to re-comment whichever line you uncommented previously before uncommenting anything else.
8. Turn Raspberry Pi Into a Headless Computer
In cases where your Raspberry Pi refuses to cooperate with external monitors—possibly due to hardware issues or damage—converting it into a headless system can be a practical solution. This approach allows you to bypass the need for a monitor, keyboard, or mouse, controlling the device remotely by using the Secure Shell (SSH) protocol for secure access and management from another computer.
To achieve this, start by removing the memory card from your Raspberry Pi and connecting it to a different PC. Create a new file named ssh on the card; this action will automatically enable SSH mode on your Raspberry Pi upon startup.
Additionally, you’ll need to prepare for network connectivity by creating another file named wpa_supplicant.conf. This file is essential for connecting your Raspberry Pi to a Wi-Fi network automatically. Using a text editor, open the wpa_supplicant.conf file and input the necessary network configuration details:
country=US ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev update_config=1 network={ scan_ssid=1 ssid="" psk="" }
- Change the two-letter country code in
country=USto your own country code. You can check your two-letter country code through the ISO website. - Type your Wi-Fi name or SSID within the quotation marks of the
ssid=""line and your password in thepsk=""line. Hit “Save.”
Check everything, eject, then plug the memory card back into the Raspberry Pi. Once powered up, the Raspberry Pi should automatically look for your Wi-Fi SSID, try to log in with the password, and let you connect to it via SSH.
Tip: if you can’t use Open with to open the file in a text editor, you can temporarily add “.txt” at the end of the filename to associate it with Notepad. Remove that part after pasting the code.
You can use an SSH client like PuTTY to log into the Raspberry Pi as long as it’s on the same Wi-Fi network as your PC.
Got any older devices that lack Wi-Fi? You could turn your Raspberry Pi into a Wi-Fi bridge to bring it online.
Troubleshooting a non-responsive Raspberry Pi monitor can seem daunting at first. However, with the right approach and a bit of patience, most issues can be resolved. Now that your monitor is hopefully up and running, why not use it to try some exciting projects? Building a NAS server with your Raspberry Pi can be a great way to start. It’s a perfect project for storing and sharing files across your network. Alternatively, turning your Raspberry Pi into a Minecraft server offers endless fun for you and your friends by hosting your own custom gaming world.
Tip: now that your external monitor is working again, why not turn your Raspberry Pi into a video conferencing station?
Frequently Asked Questions
Why do I need to remove the memory card when I can see the config.txt file in "/boot/" anyway?
While it is visible in “/boot/”, you certainly can’t save the file while the Raspberry Pi is running. It will show a warning message, telling you that you don’t have enough permission to access the file.
What's the difference between "#hdmi_force_hotplug=1" and "hdmi_force_hotplug=0"?
Truth be told, they’re the same thing. It’s probably just built in like that to follow a format, making it easier to access. You can deduce that there’s no difference between #hdmi_force_hotplug=1 and hdmi_force_hotplug=0, as the value of hdmi-force-hotplug can only be either 1 or 0. You’ll have a hard time deducing that #config_hdmi_boost=4 can actually have five values (0, 1, 2, 3, and 4) instead of just two (0 and 1).
Are there any other SSH clients besides PuTTY?
Yes. KiTTY is a fork of PuTTY that has more features. Solar-PuTTY, on the other hand, looks nothing like PuTTY and lets you see all of your connections as tabs in a single interface. Meanwhile, SmarTTY looks like an IDE and lets you transfer files through SCP.
Image credit: Unsplash. All photos and screenshots by Terenz Jomar Dela Cruz, unless credited otherwise.
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