What should I check first if I see symptoms of HDMI not working?

First, proceed with the ‘Check monitor power and input source’ step. Bad input source is the most common cause of 'no signal'. We recommend that you avoid changing multiple settings at once and check to see if your symptoms change after each step.

How do I check for a possible cause ‘input source or cable problem’?

If there is no change in the first step, compare the steps in order, including ‘Reconnect the video cable and use a different cable’. If symptoms disappear immediately after certain actions or the conditions for their occurrence change, this can be an important clue in narrowing down the cause.

No picture when connected via HDMI: When do I need professional inspection?

Even if you follow the above solution steps in order, if the HDMI not working symptom repeats or hardware abnormal signals such as a burning smell, abnormal noise, overheating, or component recognition failure appear together, we recommend backing up important data and having a professional inspection.

PC FIX

Computer Troubleshooting Guide

Display

Problem with no screen when connected via HDMI

If you are seeing the “No HDMI” symptom, potential causes include input source or cable issues, or port damage. Cross-testing the input source, cables, ports, and then other monitors can help isolate output device and PC issues.

Solving Order
We've organized the methods starting with the simplest and least expensive ones. Please check the solutions one by one, starting from the top.

Do you have these symptoms?

No HDMI
No HDMI signal
HDMI connection screen does not appear

main causes

Input source or cable problem
port damage
Output mode settings

How to solve

Please check them in order from the top. If the issue is resolved, you do not need to proceed to the next step.

Checking monitor power and input source

Bad input source is the most common cause of 'no signal'.

Difficulty Easy time 2-5 minutes cost 0 won

1Verify that the monitor power LED lights up.
2Directly select the actually connected HDMI/DP input from the OSD menu.
3Also reconnect the monitor power cable.

confirmation point

After these steps, see if the “No HDMI” symptom decreases or disappears. If there is no change, also check for possible input source or cable issues in the next step.

Reconnect the video cable and use a different cable

You can quickly check for loose connections or breaks in cables.

Difficulty Easy time 5-10 minutes cost 0 won

1Turn off your PC and monitor.
2Unplug the HDMI/DP cable from both sides and connect it securely.
3If possible, use another good cable.

Cross-testing with different video ports and different monitors

Isolate whether the problem is the monitor, cable, or GPU port.

Difficulty Moderate time 10-20 minutes cost 0 won

1Use a different output port on the graphics card.
2If possible, connect to another monitor or TV.
3If you are using a gender or docking station, connect the PC and monitor directly.

Check graphics card connection location and POST diagnostics

A bad connection or RAM/GPU POST failure on a PC with a discrete GPU can cause what appears to be a no screen.

Difficulty Moderate time 10 minutes cost 0 won

1If you have a separate graphics card, make sure the monitor cable is plugged into the graphics card.
2Check the motherboard CPU/DRAM/VGA/BOOT diagnostic LED or beep pattern.

Install RAM/GPU and check auxiliary power

Poor contact or missing GPU auxiliary power can cause No Video.

Difficulty Advanced time 15-30 minutes cost 0 won

1Power off your PC and disconnect the power cable.
2If you have experience working inside a PC, check that the RAM and GPU are fully seated in their slots.
3Make sure the GPU auxiliary power connector is fully connected.

Request hardware inspection or repair

If the same remains after checking the software, you should check whether the part itself may be defective.

Difficulty Advanced time 30 minutes or more cost Possible occurrence during inspection/repair

1If possible, run manufacturer hardware diagnostics.
2During the warranty period, official service inspection takes priority over arbitrary disassembly.
3Back up important files before repair.

Frequently Asked Questions

We've put together a list of things we frequently check regarding this issue.

Related issues

If the symptoms do not match exactly, please check the issue below.

Display

Problem with no screen on DisplayPort connection

Among screen problems, the “No DP” symptom may be related to cable/port/input source problems or monitor power saving handshake. Cross-testing the input source, cables, ports, and then other monitors can help isolate output device and PC issues.

View solutions →

Display

Problem with No Signal appearing on the monitor

If “no monitor signal” occurs repeatedly, it is better to narrow it down to a faulty input source, bad cable or port, rather than changing several settings at once. Cross-testing the input source, cables, ports, and then other monitors can help isolate output device and PC issues.

View solutions →

Display

The monitor is turned on but the screen is black.

When troubleshooting a monitor that is turned on but the screen is black, it is important to rule out causes one at a time. Based on the “monitor is powered on but black screen” symptom, check for problems with the input signal, brightness, or panel, then proceed to the next step. Cross-testing the input source, cables, ports, and then other monitors can help isolate output device and PC issues.

View solutions →

Display

PC turns on but there is no display

If the PC powers on but there is no display, first check the monitor input and cable, then the graphics card and RAM POST status. Check the display output path one step at a time.

View solutions →

Look for other symptoms too

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