Question PC just stopped working one day... Power cycles

dosmastr

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Jan 28, 2013
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Hi all,
I have a PC I built back in 2014 it's a haswell 4570

It began having issues when I wouldn't get a vid feed a few days after upgrading the video card. (There were several successful issue free boots between new install and issues)

The PC wouldn't give a video feed unless the bios hit a hard stop. (You have failed to boot several times, want to change a setting?) Once this happened it would boot fine, no errors or issues.
CPU and other fans are spinning, though the GPU fans were a little slow to come on.

Thinking psu, I replaced it with a thermaltak, the old antec 430watt was probably being asked for too much from the new GPU when under load.

Still no feed feed without a bios stop.
I thought maybe the new GPU was problem, so I put the old one back in, no joy same issue.
Checked voltages, and all were within spec except the ram which was a little high because I had some 1.65v sticks running 1.55 but under-clocked from 2133 down to 1600 and some 1.5v sticks doing same (loooong story.....) Made this change years ago though. Bumped to voltage another .005v. And that was the last time it booted.

Now it only power cycles.. turns on for 10seconds, off for 5seconds, on for 10 seconds. Off for 5, Repeat.

When it was still psudo working I did memtest and came up fine. I tried the other pcie 16 slot with both the old and new GPU, no change.
i pulled all but one stick of ram and tried all 4 slots, then repeated with all 3 other dimm sticks.

i pulled ALL the RAM. No ram installed and hdds all unplugged (it was shutting off right as they finished initializing, didn't want to break them) now it turns on for 30 seconds before shutting off for 5, and repeating. I pulled the CMOS batt and unplugged it for 30 seconds several times trying to force the bios stop which worked previously, no joy.

its a new psu from a quality maker, does that mean it's now likely the mobo, CPU or both?

im just trying to avoid buying 6 year old mobo to go with this 6 year old CPU only to find I should have just bought a new CPU or both.... And at that point should have gotten at least an lga 1151...or something from AMD.

i don't use this pc crazy much anymore, so I'm trying to avoid dumping cash in, but if it's pay 125 for a 6 year old board or 125 for a 2 year old one and another 75 for a newer CPU... I'd rather the furtureproofing.

opinions solicited
 
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InvalidError

Titan
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Dying PSU may have fried the motherboard.

I have repaired a bunch of PC PSUs over the past ~20 years for friends and family. The most common failure mode (90+% of non-catastrophic failures) are simply old or under-spec'd capacitors. When capacitors go bad and practically open-circuit, they let large transient spikes through (since getting an oscilloscope, the worst I have seen is 18V on a 5V line) and those can be very bad news for anything powered from affected rails.
 
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dosmastr

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Thank you much,
Flipping antec used to be GOOD....
Any guesses on the CPU?

2 years ago I did have the original antec making noise while under load but after it was replaced the PC was good for two more years.
View: https://youtu.be/0lDF7sNMNp4

Just like you said, non-catastrophic but a failure, but again this was 2 years ago.
 
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