What to do if the monitor won't turn on

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2023-12-17 03:44

Often the cause of the problem lies not in the display itself, but in the computer. Check each option and solve the problem yourself.

1. Make sure you have power

Before proceeding with further diagnostics, you need to make sure that the monitor is receiving power. This is indicated by the LED on the front panel, which should be lit or blinking in one of the colors.

If the indicator is off, check the power buttons on the monitor and extension cord: it is possible that someone or you yourself accidentally pressed them while cleaning and did not notice.

If everything is in order there, then the reason may be in the cable. From the side of the plug, it is fixed in the outlet quite clearly and reliably, but it is simply inserted into the monitor power connector. The wire may have moved slightly in the socket and the contact is broken.

Try to insert it a little more into the connector and check the indicators. There may be problems with the cable itself. To eliminate them, replace the wire with another, for example, from the computer's power supply - they are suitable (unless it is a model with an external adapter).

2. Check the video cable connection

Make sure the signal wire is also securely fixed. HDMI and DisplayPort must be fully inserted, and VGA and DVI are additionally secured with screws on the plugs. Then do the same with the connector on the other end of the cable that connects to the computer.

If possible, try replacing the wire or connect through a different connector. For example, if your video card and monitor have multiple ports, use DVI instead of VGA or HDMI. Or vice versa.

Another cable can simply be connected to the wrong video card. This happens when the motherboard has a pin for integrated graphics, but a discrete adapter is involved. If you have recently disconnected the monitor wire, check if you have connected it correctly. The plug should be plugged into the bottom connector, separate from the main port group.

3. Switch the signal source

Some monitors with multiple ports have a function to switch between signal sources. Like on TVs. The correct connection may not be detected automatically, and then, of course, there will be no image on the screen.

Switch the signal source using the Input or Source button with a square with an arrow inside. For details on this function, see the operating instructions.

4. Make sure the monitor is working properly

If none of the previous tips helped, the monitor might be broken. The easiest way to eliminate this is to test the display on another computer. Ideally, just swap monitors with someone else for the day.

However, there is another way. Disconnect all wires from the display except the power cable and turn on. If a message about no signal or any other information appears on the screen, then everything is in order with the monitor and the problem is in the computer.

If the display remains black and no indicators on the case are lit, the monitor will have to be carried to the workshop for repair.

5. Rate the reliability of your contacts

RAM, video card and other components are installed in slots on the motherboard. If you recently changed them, cleaned them, or removed them from the slots for any other reason, there is a possibility that the components are not fully inserted. Due to poor contact, there may well be no image on the monitor.

To check, disconnect the power cable from the computer, carefully remove the side cover by unscrewing the screws at the end of the rear panel. Examine the video card and RAM sticks. Make sure they are inserted straight and all the way. The latches on the sides of the RAM should be closed, and the video adapter should be fixed with a screw to the chassis chassis.

6. Check memory

The computer may not turn on due to one or more problematic memory modules. Usually the system speaker makes several sounds, although not always.

On a de-energized PC, remove the cover. First, take a photo to get your memory back in place after experimenting. Then spread apart the latches on the edges of the RAM slots and remove the modules. Clean the contacts with a regular stationery eraser and rub with rubbing alcohol if available.

Put the memory back in place, reconnect all cables and check if the computer works. If not, then you can still try to remove all RAM modules, leave only one or swap them in the slots, trying to start the PC after each manipulation.

If an image still appears on the monitor, then the problem is definitely with the memory and it will be necessary to replace the defective modules with new ones.

7. Test the video card

Of course, a burned-out video adapter cannot display any picture and the screen will remain black. To check, taking precautions, disconnect the internal power cable from the video card. Unscrew its fastening screw, then slightly bend the slot latch and carefully pull out the adapter.

Clean the contacts of the card with an eraser and alcohol, then reinstall it and, collecting everything in the reverse order, try to start the computer again.

Another option is to replace the video card with another, obviously working one. If this helps and a picture appears on the monitor, you will have to fork out for a new video adapter.

8. Check the power supply

If all else fails, then most likely the cause of the problem lies in the power supply. This can only be verified with the appropriate skills. At the very least, you need to have a multimeter on hand and be able to use it. If you are confident in your abilities, then act like this.

With the case cover removed, locate and disconnect from the motherboard the longest connector with the most wires that come from the power supply. Unfold a paper clip and connect the resulting jumper between the contact with the green cable and any of the contacts with the black wire to simulate the PC power-on signal.

Orange	+3.3 V
Red	+5 V
Purple	+5 V
Yellow	+12 V
Blue	−12 V

Next, put the multimeter in the DC voltage measurement mode. Press the black probe to any contact with the black cable, and then alternately touch the red probe to the contacts of the yellow, red, orange, purple and blue wires. Compare the values with those in the table above.

If the voltage is absent or differs from the reference by more than 5%, the power supply will probably have to be repaired or replaced. If you have a working unit, you can immediately try to install it instead of the standard one and look at the result.