PC starts automatically when plugged in and gets shut down after some time

Question

My desktop was working fine till yesterday but suddenly it logged off. When I tried to start it again it started but shut down again after some time. This is now happening continuously. The PC starts automatically when I plug in.

I tried to swap the POWER and RESET switch on the motherboard but that did not work. Finally I used a screwdriver to short and my PC started working. But I don't want to use a screwdriver everytime to start my PC.

Can anybody suggest me how can I start my PC using POWER and RESET switch?
I have a PC with an Intel motherboard.

Solution

Sounds like you have an intermittent connection problem. To start, if the motherboard does not exhibit the same behavior with the power and reset button attached as not attached, it probably is not the MB; it is probably the buttons. But, if it does the same thing when you isolate the MB from everything else (disconnect buttons and technically all other hardware except CPU and RAM just for thoroughness), it is probably the MB or the PS.

Test the resistance of your power button with a multimeter. It should normally be infinite (usually read as "1") ohms. Then, with the multtimeter, push the button, it should read near 0 ohms.

Test your reset button as well the same way, it should exhibit the same behavior.

Also check to make sure the back plane of you MB is not shorting the power pins by reading the resistance across the pins, it should read something other than near 0 ohms; not sure what though could be high, could be low. Put a small smount of pressure on the board with your fingures at that location, and test resistance at the same to see if it changes, it should not.

Problem with your question is the power button and rest button typically (not always) do the same thing and usually can be swapped with each other. So if you swapped them, and it still came on right away, then either both buttons are bad or it is something other than the buttons, like a short on the back plane; but then it should have started and /or turned off with the buttons disconnected as well..

Could be you connectors themselves are bad also if the screwdriver works but the buttons do not and they test properly with a multimeter. You could do the same test to the buttons with them connected to the MB out of the computer and test the resistance of the buttons on the MB itself, it should do the same things as above. Infinite resistance usually, 0 when button pressed.

Comments

[Ramhound]

When you have to short something to get hardware to work it means its time to replace your hardware. I would simply replace the motherboard at this point.

[Damon]

Shorting the power pins is exactly what the power button does. He just replaced the power button with a screwdriver. I would not recommend a MB replacement simply because the computer turns on properly when a screwdriver is used.

[Damon]

What do you mean it shut down? Did it turn off? Did it shut down like an OS usually does? and What do you mean by your PC started working? It doesn't shut down any more? Or it simply turns on like normal? Or both?

[Rohan]

When POWER and RESET pin is connected to mobo and when i plug in ,PC starts for while and shuts down normally.This start-shut down cycle repeats continuously.But when i remove POWER and RESET switch and use screwdriver to short , PC starts normally and does not get shut down after some time.

[Damon]

Focus on the power button and everything inline with it down to the board. Something has got to be shorting the power pins. Pushing the power button while the computer is on while exhibit this behavior. Try using reset button as the power button and leave the reset button disconnected. This will only work if the reset button is not a momentary type switch which I think sometimes they are.

[Rohan]

Thank you for your reply.I will follow your steps and let u know if it is working or not.

[Rohan]

Thank you for your reply.I kept only POWER pin connected and removed RESET pin.Then I pulled out POWER wire little bit and switched on my PC and magic!!!Pc started working fine. :-) Upvoting your answer for your valuable answer and time :-)

[Damon]

Glad you were able to isolate the problem! Hardware problems can be difficult to drive out sometimes! Accepting this answer would be kinda cool too if it solved your problem. :)