power up problem after unplugged
Posted 16 May 2005 - 01:20 PM
Posted 16 May 2005 - 03:15 PM
When the computer is turned off but still plugged in, there will be a standby voltage that is constantly fed to the PSU. This, I think, will ensure that the PSU's capacitors are not discharged completely & will also keep the components from getting cold.
When the computer is turned on, there is often a very short period between the PSU powering up & the system powering up. This is because the mobo won't power on until it receives the POWER GOOD signal from the PSU. The power good signal is only sent after the psu has stablised. Its possible therefore, that it is taking longer to stablise after the power has been disconnected for any length of time due to the reasons stated above.
You could probably test this theory by running the PC, turning it off, disconnect the power lead for a couple of seconds then reconnect & power the system up. If it works OK after doing that, then I could be right.
I am guessing completely though & anyone else please feel free to tell me that I am taking a load of b****ks here.
Posted 16 May 2005 - 07:08 PM
Posted 16 May 2005 - 08:19 PM
jgalt how long do you have to leave it pluged in for till the computer will finally start?
Also DO NOT under any circumstance try and open the psu for a look doing so can kill you because of the voltages they store even when unpluged
Posted 16 May 2005 - 11:32 PM
Thank you both for your help.
Posted 17 May 2005 - 12:07 PM
Well Samm in therory that is a very good guess and must be the case but I wonder why the capacitors would discharge over a short period, I could see this happenning if left unpluged for months. I am thinking that one or more of them are going to fail or are leaking, what do you think?
Doby - as usual, I think you're right. I have already been informed that you are the PSU expert!
Posted 17 May 2005 - 07:57 PM
I see far to many of these cheap ( I hate that term lets say inexpensive) psu's not having enough amps to support modern cpu's mobo's and graphics cards.
jgalt in this case I think I would replace it just to be on the safe side cause when a psu fails it can be troublesome to pinpoint not to mention the fact that it can also damage other components.
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