Every few days I have a problem starting my computer. Pressing the 'on' button does nothing. Shorting out the start button proves that it is not faulty.
I have found that if I switch off the mains supply, then switch it on again at the same time that I press the button, I get lucky after several attempts and it will start. It behaves itself for another few days then the fault reappears.
The same button also provides for switching off, so I assume the power up is some form of toggle circuit. ButI don't know whether it is in the power supply or on the main board.
It seems you have isolated the problem to either your motherboard or power supply. Try to power your computer with a power supply that you know works and then you'll be able to tell where the problem is. I have had issues similar to this before and the PSU or motherboard were the only parts at fault.
When one person suffers from a delusion it is called insanity. When many people suffer from a delusion it is called religion.
Although this has never happened to me before but perhaps one of your devices other than the motherboard is failing and causing the power supply to shutdown. Fans seizing? Hard Drive dieing? Graphics card fault? Bad connections? I don't have your machine here so it's hard to tell exactly the cause.
Sometimes a good whack can solve a problem like knocking some connections clean of oxidation. Who knows?
When one person suffers from a delusion it is called insanity. When many people suffer from a delusion it is called religion.
Hi Pebe..the other day i had similar syptom like that of your sustem.Took out the peripherals one by one hoping to 'get the problem gadget.Cleaned the whole motherboard for dust..Took out the power supply and 'jumped the green to to black,it turned on the internal fan which would suggest that it is OK..I opened the power supply for dusting and visual inspection since its out anyway..I saw a bloated top capacitor,1000 uf ,10v at the 5V supply..replacing it restored my system..and I thought it was the motherboard..
I watched the long blurb about the D-type and wondered how, as drawn, the same push button could turn the PS off as well as on. As the explanation was about to be given and the mystery unravelled(?) at 5.42 minutes, the display stopped. I tried a second time and the same thing happened.
The PB is unable to turn the PS off via the D-Flip flop. I think he's leaving out other parts of the circuit for simplicity. To turn the PS off a high must be on D and then clocked in. There would have to be another wire going from the button to another chip (possibly the BIOS) to signal an interrupt so that the OS can begin its shutdown sequence. Forceful shutdown by holding the PB for a few seconds is probably handled by the BIOS and it just clocks a high into the D-FF after those few seconds has elapsed.
When one person suffers from a delusion it is called insanity. When many people suffer from a delusion it is called religion.
Computer not starting
Posted - Jan 03 2011 : 11:49:21 AM
