canoli wrote:Never mind. From what I can gather a PSU won't fail slowly it will either work or it won't. Sound right? Maybe it's my mobo....something weird is happening though. Last night I came home and the system was dead. DOA. I pulled the PSU, checked it out (visually, not with a meter) and all looked normal - no bulging capacitors or funkiness inside. Put it back together and the system fired up again. Don't know what the ^(*& is going on...
absurdity wrote:Also worth noting that DOA = Dead on Arrival. Clearly not the case if you've been running the system for two years
canoli wrote:gotcha - although I'm not talking about a "PSU Tester" gadget - I mean a multimeter. There's no simulation going on it's simply reading the voltage at the pin. You basically short-circuit the unit, plug it in and see what each cable reads.
canoli wrote:okay sounds good. No oscilliscope available so I'm stuck with a multimeter. But the process involves jumping across pins 12 n 13? (i think it's 12/13, the Power On and a Grnd). So that's not really shorting it I guess - or maybe it is...I'm a little weak on the terminology. But you sound like you know what you're talking about, can I ask your opinion - is it worth pulling the unit and doing voltage checks? I'm still getting the symptoms - cold boot stutters with a few tries...then finally completes. Thanks!
canoli wrote:Okay so we're speaking the same language ... So, is it worth checking voltages on each cable, esp the 24-pin, seeing what it reads after shorting (forcing it to power up) the unit? I guess if anything checks out way out of tolerance it could be a worthwhile test...yes?
sluggo wrote:If you can get the machine to boot, you can test the voltages under load. Put your voltmeter's ground probe into any cable header with a black wire coming out of it, then probe the 24-pin connector with the voltmeter's V+ lead.
sluggo wrote:Try booting the machine immediately after a shutdown - if it boots right away, the current sense may be the problem. Run the test exactly the same way a few more times to confirm.
canoli wrote:sluggo wrote:If you can get the machine to boot, you can test the voltages under load. Put your voltmeter's ground probe into any cable header with a black wire coming out of it, then probe the 24-pin connector with the voltmeter's V+ lead.
The machine boots fine - after 3 tries. But once the machine is running the 24-pin cable is connected to the mobo header. How can I probe it while it's connected? I'm sure I misunderstand you but maybe you can explain it again if you don't mind.
canoli wrote:sluggo wrote:Try booting the machine immediately after a shutdown - if it boots right away, the current sense may be the problem. Run the test exactly the same way a few more times to confirm.
It never "boots right away" it always stutters, meaning the fans will spin, the lights go on...for 2 or 3 seconds, then it shuts down. It immediately starts back up (on its own) and repeats the same process. (that's 2) On the 3rd try it will go through all the way and boot into Windows as if nothing was wrong. It's been doing that since I can remember and I never cared until the other night when I came home and tried to wake the machine from sleep, found it was totally dead. It came back to life after I tinkered around a bit and as I type it appears nothing is wrong with the system. It's only that damn boot process that shows something is amiss.
Thanks again for your replies S...I appreciate it.
sluggo wrote:...insert the V+ probe into a housing, right alongside the wire that carries the signal you're interested in (+5V, PON, etc ..). When you get in far enough, the tip of the probe will make contact with the metal terminal crimped onto the end of the wire and you can measure that signal. There's nothing to worry about - you can't break the connection nor damage the connector itself. This technique is standard practice in the industry.
I guess I'd start from ground zero. Do a thorough blowout of the dust in the PSU and the motherboard.
sluggo wrote:Re-flash your motherboard's BIOS and reset it to default condition.
sluggo wrote:If you have a spare motherboard around try booting that with this PSU.
sluggo wrote:Tell me more about the UPS. You've got a lot of power demand at start-up - what's this UPS rated for? Also, does the machine go through this restart sequence when the UPS is bypassed and the machine is plugged directly into the wall?