I recently assembled a computer and it frequently crashes. No blue screens but complete shutdowns; sometimes it will not post (no beeps). After searching a lot I finally figured the problem is power related but nonetheless it is weird and I wonder if I am overlooking something.
Using a multimeter, I:
checked the voltage on the +12V and +5V rails when it does not post; both are below the limits.
checked the voltage on the +12V and +5V rails when it does post and both are fine.
checked the AC voltage. Voltage is a bit low at times (210~V) but within European regulations and the psu specifies it can handle 100-240~V input.
checked if there is propper ground in the room: there is a current when connecting ground and one of the other wires.
The crashes/post failures are appearing completely random, ie I can play skyrim for two hours with no problem and other times it shuts down while idle or doesn't boot at all. Naturally I checked AC voltage when there was no post; it was fine. There is a delay between turning on the pc and me grabbing the multimeter of course, however I would expect that if a brownout were responsible, the psu would stabilize after the input current corrected itself. Such is not the case: if it doesn't provide +12V then it will not until I disconnect it from the outlet and reconnect it again.
The irreproducibility is annoying. If it would never work, I could be certain the psu is broken. Working 90% of the time, it might be hard to prove that it is indeed broken; I assume this is also why it managed to pass quality control checks.
As for relevant specifications:
550W psu
amd phenom II 965BE (stock cooler no overclock)
amd radeon hd 6850
1 hd
1 dvdrw
2 case fans
1 cardreader
Using a multimeter, I:
checked the voltage on the +12V and +5V rails when it does not post; both are below the limits.
checked the voltage on the +12V and +5V rails when it does post and both are fine.
checked the AC voltage. Voltage is a bit low at times (210~V) but within European regulations and the psu specifies it can handle 100-240~V input.
checked if there is propper ground in the room: there is a current when connecting ground and one of the other wires.
The crashes/post failures are appearing completely random, ie I can play skyrim for two hours with no problem and other times it shuts down while idle or doesn't boot at all. Naturally I checked AC voltage when there was no post; it was fine. There is a delay between turning on the pc and me grabbing the multimeter of course, however I would expect that if a brownout were responsible, the psu would stabilize after the input current corrected itself. Such is not the case: if it doesn't provide +12V then it will not until I disconnect it from the outlet and reconnect it again.
The irreproducibility is annoying. If it would never work, I could be certain the psu is broken. Working 90% of the time, it might be hard to prove that it is indeed broken; I assume this is also why it managed to pass quality control checks.
As for relevant specifications:
550W psu
amd phenom II 965BE (stock cooler no overclock)
amd radeon hd 6850
1 hd
1 dvdrw
2 case fans
1 cardreader
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