Computer refuses to turn on

lucasbytegenius

lucasbytegenius

Well-Known Member
Ok, I have my machine hooked up to a switchbox that I turn off every time I shut down my computer, and the way I have it set up, when I turn it on my computer will turn on as well.
Well, it hasn't done that lately, it's been a pain in the youknowwhat to get it to turn on, and basically here's what happens:
I turn the switchbox on
A low whine emits from the machine, but it doesn't turn on, or respond to a power button punch
I power the switchbox off, then turn it on, the machine whines again, I shut it off, then on, and so on until it powers up, and then when it does it's got the fans going at full speed and it doesn't post, then I shut off the switchbox, turn it on, then punch the power button, the machine turns on for 2 seconds, then powers off, and I punch the power button again, same thing, and what's funny is that I end up holding the power button in while the computer does that 2 second power up then down thing, almost like a car hacking and sputtering to start lol :D
All I can think of is that I have a bad/underpowered PSU, it's 400W afaik.
Any thoughts? Sorry for the long post, kinda needed to vent a bit :o
 
You are probably not getting the Power OK signal from the PSU - at least one voltage is out of spec for too long. You could check that signal at the MB power connector, and the bus voltages with a multimeter. The cause may be more difficult to find although most likely as you noted; PSU on the way out or load has become too great.

You did not say whether the PC started fine if the switchbox is bypassed. Also whether the bus voltages are OK once the PC is up to speed.

Edit: The other factor that I'm not sure about is that by disconnecting the PC entirely from power whether it affects discharge of the cmos battery. The 5V standby power that is normally on is powered down.
 
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Nanobyte said:
You are probably not getting the Power OK signal from the PSU - at least one voltage is out of spec for too long. You could check that signal at the MB power connector, and the bus voltages with a multimeter. The cause may be more difficult to find although most likely as you noted; PSU on the way out or load has become too great.

You did not say whether the PC started fine if the switchbox is bypassed. Also whether the bus voltages are OK once the PC is up to speed.
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Does the same thing without the switchbox, and at other people's houses as well.
Yes, it seems fine once it finally starts up, and there are days when it doesn't do that.
I have no access to a multimeter, so I can't check the signal. This PSU is like 6-8 years old I believe, I just pulled it out of an old custom rig when my last cheap PSU blew up. Very heavy thing it is too, though that isn't of interest.
 
Actually, it is of interest. A heavy power supply implies that beefier components were used in its construction than in your average bestec or hipro. That's not to say it's not the problem here, but it does give better odds of your PSU being...eh...not crap.
 
I agree with Drenlin that the heavier construction indicates better quality for a given rating.

You can buy a digital multimeter on sale for about $12 yet it's surprising how many people spend thousands on a PC build without even checking the voltages are correct before risking power up.

I was hoping that someone would address my "edit" comment. It is possible that the CMOS battery is discharged to the point it is about to fail and the load of start up is enough to upset the CPU reset. I would change the battery (doing all the necessaries) and get rid of the switch.

For years I have assumed, but been unable to confirm, that the standby voltage powers the RTC and CMOS memory providing the PC is plugged in and breaker "On". It would be common sense not to use the CMOS battery unless really needed.

Edit: It is assumed the PSU is adequate size since it worked fine for a while. The only factors that would account for deterioration with time imo are additional hardware added, PSU failing or battery issue.
 
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Nanobyte said:
I agree with Drenlin that the heavier construction indicates better quality for a given rating.

You can buy a digital multimeter on sale for about $12 yet it's surprising how many people spend thousands on a PC build without even checking the voltages are correct before risking power up.

I was hoping that someone would address my "edit" comment. It is possible that the CMOS battery is discharged to the point it is about to fail and the load of start up is enough to upset the CPU reset. I would change the battery (doing all the necessaries) and get rid of the switch.

For years I have assumed, but been unable to confirm, that the standby voltage powers the RTC and CMOS memory providing the PC is plugged in and breaker "On". It would be common sense not to use the CMOS battery unless really needed.

Edit: It is assumed the PSU is adequate size since it worked fine for a while. The only factors that would account for deterioration with time imo are additional hardware added, PSU failing or battery issue.
Click to expand...

According to my BIOS, the voltages on the battery and everything else are normal, and I can't get rid of the switch, because that would mean I have to unplug the cord from the back of the computer every time I powered it down and my dad insists that all computers have the cord unplugged so that they don't waste power, which I'm sure it really doesn't use that much when it's off, but you can't really tell him that :o
Also, the hardware in the machine now is the same hardware that was in there before the PSU change, and as I said, it does the same thing when it is plugged in, though a little less often.
Right now, I'm pretty much broke and can't even afford $12, pretty sad, I'm still recovering from my $215 iPod Touch purchase a few months ago. I live entirely on gift money it seems, can't get a job yet.
 
Nanobyte said:
I'm out of ideas and you're out of money.
Click to expand...

Yeah, it's really sad. Thanks man for your suggestions :):good: Appreciate it.
If I come across a PSU soon I'm going to try putting it in and seeing what happens.
Planning to build a new rig this year anyway, so it probably doesn't matter that much, I can still use it as it is.
 
Yeah, I would say you have a faulty psu. They do weird things like that when they are faulty.
 
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