Test the power supply with a power supply tester to easily test all pins at the same time. Or for the same price as a cheap tester you could by another cheap power supply. If its a intel cpu then finding a new matching motherboard is not as likely as amd so it probably isnt worth it. Even if you find a mb you probably spend more on yearly electrical costs running on old hardware than just buying a $250 new zacate or atom pc that may be just as fast as the older pc.
Matthias On Nov 7, 2011 7:04 PM, "Adam" <[email protected]> wrote: > Hi all! I have a hardware problem here, but can't figure out whether the > problem is the power supply or the motherboard. Either way, I'm aware > something is very wrong and I'm already shopping for a new system. > However, if this one can be repaired inexpensively enough I'd like to keep > it as a second system. > > This is a bottom-end Compaq desktop tower. Once it's powered up, it keeps > working as well as ever. The problem is powering it up. When my UPS is > turned on or the AC cord is plugged into the tower, the LED on the back of > the power supply that's supposed to be on whenever there's AC flashes > quickly, and a faint "tick" is audible each time it flashes. The tower > does nothing else; it doesn't even start to spin the power supply fan. > Once AC power is removed, the LED gradually flashes more slowly until it > stops completely, which takes 30-60 seconds. > > The first time this happened was two weeks ago, and somehow after a few > hours the problem, whatever it was, "fixed" itself. This past weekend I > powered it down for the first time since then, and it did not power up at > all. During that time, I used my DMM to measure one of the peripheral > power connectors (the kind that would power a PATA drive), and discovered > that when AC is applied, the +12V line rises within about half a second to > about 0.67V and stays there. When AC is removed, that voltage gradually > drops to zero as the LED flashing slows down. When the +12V line is steady > at about 0.67V, the +5V line is steady at about 0.27V. > > What I discovered yesterday was that if I disconnect the power supply from > the motherboard (just the 20-pin power connector, not the case fan power or > any other power connector), apply AC (at which point that LED comes on > steadily), and /then/ attach that 20-pin ATX motherboard power connector, > the system then powers up normally and runs. (Yes, I already know I'm not > supposed to touch that while power is on!) > > Obviously something is very wrong here. My question here is, is it more > likely that the problem is the power supply or the motherboard? (Either of > which I can replace myself.) Or could it be something else that I haven't > considered? This system also seems to go through about one internal DVD > burner per year, but I don't /think/ that's related. Can any of you > hardware experts suggest anything? Thanks VERY much in advance! > > Adam > > ______________________________**_________________ > Mid-Hudson Valley Linux Users Group http://mhvlug.org > http://mhvlug.org/cgi-bin/**mailman/listinfo/mhvlug<http://mhvlug.org/cgi-bin/mailman/listinfo/mhvlug> > > Upcoming Meetings (6pm - 8pm) MHVLS Auditorium > Dec 7 - An Intro to Chef > Jan 4 - Recovering the Brownfield: Revitalizing Open Source Projects > Feb 1 - Home Networking Made Simple with Amahi Home Server >
_______________________________________________ Mid-Hudson Valley Linux Users Group http://mhvlug.org http://mhvlug.org/cgi-bin/mailman/listinfo/mhvlug Upcoming Meetings (6pm - 8pm) MHVLS Auditorium Dec 7 - An Intro to Chef Jan 4 - Recovering the Brownfield: Revitalizing Open Source Projects Feb 1 - Home Networking Made Simple with Amahi Home Server
