Just replaced mobo, now turns off immediately. Now what?

Wow! What a great and helpful reply! Thank you enormously!

I'll get started just as you suggest, one thing at a time, and report back.

Well, I just received a replacement PSU, a Corsair RM750x (when I first built this machine, I thought I was going to have quite a few HDDs directly SATA connected, which is why I bought a 850 watt PSU. But I chose USB 3.0/3.1 Gen 2 instead, so I didn't need that much power). In high hopes, I connected it with the new cables that came with it, and turned in on.

Aargh! Same thing as last time!

If it really is my CPU, I'll just go off and kill myself :/ It was near impossible to find the cash for a replacement mobo and a new PSU, buying a replacement CPU as well is a non-starter...

But it now occurs to me that there's another, probably more likely explanation: My NZXT Phantom PHAN-001BK could well have some kind of power connection or cable problem. So what I'll try first is removing the mobo and PSU and try them externally. Unless you have a better idea?

Once again, I'm very grateful that you're continuing to help me out!

Well, that didn't help. I didn't actually remove the mobo & PSU; instead I just unplugged all the Systems Panel connections (power, LEDs, etc) and a separate Silverstone digital info display (which sat between things like the CPU fan and chassis fans and temperature probes, etc). Then I shorted the two power pins to turn it on, and got the same results.

It looks like it's probably the CPU. But I don't get it: When the first symptom appeared (it turned itself off and wouldn't turn on, even as briefly as it's doing now) I hadn't touched the system or mobo or anything at all for several months! And it's impossible to believe that the current problem only occurred while swapping motherboards a few days ago. I cannot accept that.

So the only explanation I can come up with is that Intel's manufacturing quality control failed on this CPU, because when it died the CPU and the rest of the system was cool to the touch, so an overheat condition certainly didn't occur. And I also find it absurdly remote that there was a PSU glitch right in the middle of perfect functioning.

Since I really can't afford a replacement CPU -- even a used one -- I guess I'm SOL!

OK, since I've now bought two expensive items that were almost certainly completely unnecessary, I just can't impulsively think of buying yet a third, extremely expensive item! So I beg you, is there anything else I can try first that makes sense?

I'm losin it...

Oh, kind sir! I deeply apologize since it appears you thought I blamed you or held you responsible for anything whatsoever! That never even occurred to me! You are totally blameless; I was just venting my own exasperation at my situation. No, you've been nothing but extremely kind and extremely helpful -- thanks again!

The reason I went ahead and ordered a replacement PSU is that none of my friends had one available and my own other PSU is embedded into a tiny, extremely cramped case that was pure hell to install! There was no way I was going to try to remove and re-install it again. And I'm considering returning it, but not until I've resolved these issues.



First, yes, I have a connected speaker, but I've never heard any beeps at all. AndI haven't tried removing both RAM sticks, but I will. I did ensure that the one stick I left in was where Asus instructed me to put a single stick.



Another good idea, thanks. I removed everything but the mobo, the PSU, a monitor (connected to the on-board Intel graphics rather than my usual nVidia card), and mouse & keyboard. But I will certainly attempt your suggestion.

The replacement mobo came with it's own new battery, but I tried replacing it with the old one and clearing CMOS. Sadly, that didn't work.



Thank you enormously! Please don't doubt for a second that I'm anything but deeply appreciative of your valuable time and obvious expertise.



Well, I bought both the mobo and the CPU as brand new, and they are only about 3.5 years old (too old for the respective warranties, though), although I realize that the technology is older than that. But your final suggestion is excellent and is what I'm going to try next.

Only a rare individual would have dedicated so much time for me and these issues: You are indeed one of the very few!

Hi again, panathas! Well, on your wise suggestion, I took my i7-4790K CPU to be tested, and they found that it had definitely failed. They said they'd seen about 10 4'th generation Haswell CPUs fail, usually not long after the warranty expired (just like mine). They said something about how Gen 4 was the first one where they stopped soldering the leads, and used some other apparently not quite ready for prime time method, which they think is the reason for these failures.

Anyway, just today I received a brand new i7-4790K, installed it, and powered up. It entered the BIOS once, but after switching from AHSC (sp?) disk mode to RAID mode, when I booted up a red LED on the ASUS Z97-A mobo stayed lit every time and I could no longer access the BIOS properly. But here's the thing: To the best I can figure, that LED is not in the location of any of the LEDs in the manual!

On ASUS Z-series motherboards (and perhaps all ASUS mobos, I don't know) there's a circular medallion-like thing with "ASUS" printed on it (what's that called?) The LED that keeps getting lit is very close to that, on the side AWAY from the CPU, so I can't imagine that it's the CPU error LED. But the manual doesn't show ANY LEDs near there!

The official ASUS Z97-A forum hasn't seen any post but mine in quite a while (and mine never got any replies), so there's no point in asking there.

Would you be so kind as to help me figure out what error that red LED is signalling, please?

Thanks!

Right again, oh knowledgeable panathas! It was night when I looked before my last posting, but with the sun up I finally saw the printed label (I feel rather dumb!). It was the Boot Device LED, which I've straightened out, but only to a limited extent.

Before continuing with my almost infinitely frustrating story, let me answer your questions about why I'm using RAID. The answer? How does "hubris" sound? :/ Well, far in the past (OK, 3 years or so ago), when I was deep enough in the black to be buying plenty of expensive computemo components, I decided to use SSDs in all my systems for the boot device(s). But for the system under discussion, the fastest I've ever had -- and knowing that by far the biggest system bottleneck is disk access -- I decided I'd buy two Samsung high-end SSDs and connect them in a RAID 0 configuration for maximum speed. Of course I always made full partition copy backups to non-RAID HDDs, since ya never know what might happen.

Just like what's happening now, dammit! (for the record, that's certainly not directed at you, but to the capricious gods of technology).

OK, so I hit upon clearing the CMOS as soon as I woke up, which worked fine, but the BIOS defaults to AHCI, so I changed it to RAID and rebooted. (I had already connected the regular HDD containing my latest backup from April 22 to a different computer and altered the System registry hive to disable AHCI and enable RAID, because at least I'm smart enough to know how messed up it will get otherwise). But the RAID BIOS reported the 2-disk RAID 0 array had "failed". After hair-tearing testing, including trying to connect the two SSDs separately on a different system, I can only get one of them to be recognized, even in AHCI mode.

But I figure that might be normal: Maybe the second disk of a RAID 0 array lacks the necessary header and MBR, so it can never be recognized without re-formatting it. Wise sir, I ask your expert opinion: Is that the case? Or do you think that SSD is just broke? I bought a ridiculously expensive piece of software that analyzes SSDs and the SMART data and whatever in order to roughly predict its remaining lifetime, and when I last ran it about 2 months ago, it reported that both SSDs were in perfect shape and they should last another couple of decades.

I sure don't want to format the questionable one prematurely, since I own 2 or 3 pieces of software that allegedly can recover all or most data from a broken RAID set, and stupidly, my most recent backup was from a month ago, and I've made some important changes in that time. Even though the CPU had died during that period, I connected the two SSDs as RAID 0 to a different computer and kept working with them. (At least I made another independent backup on that other system, but that was also 22-April).

Damn, I'm sorry for all these endless words! I genuinely apologize for pressing your patience so hard, but I may as well finish... I can't get my 64-bit Windows 7 Pro system to boot correctly more than about half the time! I've run ChkDsk on all the disks and checked all I can think of, but curiously I have much greater success booting into full Win 7 than trying to enter Safe Mode, which after about half an hour I just lose all patience and reboot -- I've never seen it complete.

Well, I've been working on this for over 12 hours straight today, and if I keep going I'll soon be foaming at the mouth and howling at the moon, so I'm giving up for today. Whatever suggestions you may have will be as welcome as a brick of solid gold...

G'day!