Question Calling all Detective Columbos! Two old Z97's put to sleep.

Persister

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Then they can't wake. :sleep: My two Z97A fails recently. Or maybe no mystery, they are just old? First one fine 4 years. Replacement a refurbished, OK just over a month.

Witness says: System sleeping. On wake a pulsation thing where cpu fan, psu fan, & fan on psu, start to spin, then stop, then restart; repeating cycle. No post. Fans on mobo headers don't spin. No OC, no visible issues on board.

Over years I read lots about boot fails, not this. Abort start, no post, repeat. Maybe you'll say it's no different. Old mobos fail lots of ways, it's not unusual 2 fail like this?

One more thing: OS W7-64. I add cuz mobo gets order to sleep from OS. I don't know what goes on between them, or whether it involves BIOS. Doesn't matter as I can't access.

Do you have any questions Lieutenant? :unsure:
 

Persister

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A good question but that was the link. I tried other psu before buying 2nd board. Then even got a cheapo cpu to test. Z97 has led's that should show if cpu or ram error in post. But when there is no post . . . ? It is very unusual I think that psu starts, stops, repeats and is getting that order from the mobo. So mobo is not dead-dead, but is like brain-dead. And same way on 2 boards!

By logic and probabilities you might suspect that something in the system must cause same strange fail in two boards. But what could that be?

Now I will go back and try clearing cmos one more time. Digital hardware, s/w too, should not be like a mule. If you do something once it should work, or not. But in my experience there is sometimes a donkey in there.
 
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x2bc4

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I don't think is a random failure either, because I have exactly the same board and has failed to me recently the same way for no reason at all. I turned off the pc one night and didn't boot at the next morning. I'm still trying to find the source of the problem.
 
Sep 21, 2020
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Hard to imagine two boards (even they're equal) would just die with same symptom. The way you describe behaving after power on, I would say, something is drawing too much power from PSU and so PSU's protection circuit kicks in repeatedly. Or there's damage on ATX 24-pin connector -some pin there might have bad contact and so not enough current can be delivered to motherboard.
 
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x2bc4

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There is a huge (at least for me) startup power on sequence in a motherboard that needs to be checked for component failure diagnosis . I have to read more about Z97 chipset behavior when facing error signals, but i guess it's the one responsible for this bootloop. I can assure you there are no power issues as gross and simple as a pin connector, but maybe in a more sophisticated logic manner, like the absence of an expected signal or an alert is being triggered. The same symptom is presented for corrupt bios in these boards. Not my case though.
 
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Persister

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@BogdanH "Hard to imagine two boards (even they're equal) would just die with same symptom. "

That's what I thought until I learned more. Per the link in my OP, 2nd PSU was tried before replacing board. So, pin problem would have to be on the mobo. Mobo is replaced, fail repeats. That could only mean PSU male plug in primary PSU is somehow damaging female socket & it shows up delayed? The way these plugs are designed it seems unlikely. Props for thinking systemic but I don't buy it here.

Outside of this forum reports of "POST-loop" (what I think is best term) are not so rare as I thought.
 
Sep 21, 2020
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Yes, it's freakin' weird. Still, I can only imagine it has something to do with power supply at ATX 24-pin header on motherboard. Maybe some of it's pin soldered to mobo got so called "cold contact".. that is at first sight it looks (on back side of mobo) all fine, but there might be "micro gap" in tin at certain pin -that can happen after plugging in ATX connector many times.. you probably noticed ATX connector must be pushed/pulled pretty hard.
Now you have two broken mobo's, right? Did heard about "baking" mobo in oven? You can Google/Youtube for that, but main idea is, you heat oven to about 190°C and bake motherboard for about 10-12 minutes. At that heat, all soldering (tin) on whole motherboard will "reconnect" -don't forget to remove battery first, though.
I never tried that method, but it seems it worked for many (where bad contact on motherboard was the problem).
 

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