If the computer does not turn on from the power button – the causes and solutions we will consider in this publication. If you doubt your abilities and do not want to “rummage” in the iron, then it is better to appeal to professionals in the service support center, so as not to further exacerbate the situation.
#1 – No power
First of all, it is worth checking the presence of power supply. This is the most trivial of possible causes, when you try to turn on the device with the “Power” key, but it gets you nowhere.
When you use a surge protector with a light, you should check whether it is on.
In the case of the system unit you have to look at the back of the case where the PSU unit is installed (usually on top). You may see a switch labeled “0” and “I,” which are “Off” and “On,” respectively. There is a chance that someone has accidentally pressed it.
I also recommend paying attention to checking the cord that connects the PC and the outlet. What if it is not plugged into the power source. Or it might be loose. It is extremely rare, but it happens that the cable is damaged (this is especially true if you have animals in the house who like to chew on different things).
#2 – The Power Button
I am familiar with numerous cases, when a person gave the device in the hands of a non-professional wizard or tried to disassemble the laptop / computer on their own to clean the dust and replace thermal paste. But as a result, when reassembling forget to connect some cables. As a result, the start button stops working, because it was blocked to be connected to the unit or motherboard.
To solve such a problem, it is worth to find a schematic diagram of the chipset on the website of the vendor (or maybe you have the factory manual, which comes with the purchase of new components).
It is necessary to find a method of turning on the buttons located on the front of the case (not only “power on”, but also “reset”). From them there should be cords with correspondingly marked connectors. Your task is to determine where to insert them on the motherboard, referring to the information in the official manual:
Often the possible reasons why the computer does not turn on from the start button, are in the breakage of the key itself, which is essentially a switch consisting of several contacts. If one of them is damaged, then pressing it will not trigger a signal. As an option, it is worth opening the case and making the closure manually by touching a thin screwdriver to the correct terminal. For example:
But such manipulations should be performed only in accordance with the instructions and in the presence of the tool. Otherwise it is better to ask for help from specialists, otherwise you can “short-circuit” the board, and the consequences will be more disastrous.
#3 – Unfunctional PSU
When the above methods are irrelevant and the computer still does not turn on from the power button, then the problem most likely lies in the power supply. I recommend to replace it with a known good one if possible, taking it from another PC. If the system starts after this operation, then the source of the problem is found.
The second method of testing is to measure the output voltage. The module must be completely dismantled from the case, pull the cable from the socket. Then you need to provide any load, for example, connect the HDD to the PSU (preferably the one with no important data). Now find the green (which is responsible for the power supply) and any black (ground, GND or GRN) cords among the masses. Using a metal wire, short them as shown in the figure below:
Connect the unit to the mains, after which the cooler (fan) should start. It would be a good idea to measure the voltage on the purple and yellow cables with a voltmeter (tester). The first should have 12 volts and the second a little over 3 volts. If the obtained values will be drastically different, it means that the PSU is not functioning properly, gives not enough power to start. That is why people often write that “after pressing just blinked red and extinguished” (we are talking about the light indicator).
But, as mentioned above, the easiest thing to do is to connect another module to the PC to check.
#4 – And what to do with a laptop?
Here the situation is different, because the PSU is located outside. But, in most cases – there is a light on it, indicating that it is in working order.
Again, after a faulty assembly you may have forgotten to connect the fan (cooling system) to the motherboard. The laptop may start for a couple of seconds and display the error “CPU Fan Error” and then the screen will go blank.
Some models have a built-in system for providing signals of failure – with sounds (squeaking) or flashing of a special indicator. These can be used to tell you the reason why the system does not work. Detailed information can be found on the manufacturer’s website in the “Support” section or on thematic forums.
We have analyzed possible reasons why the computer does not turn on with the power button. I hope my publication was helpful.