What could be the reason why a PC runs in one case, but not in an other?

[Ranayna]

Hi everyone,

this may be more of a tech support question, but i am currently more interested in possible causes for the issue i am outlining below.

Shortly before Christmas, i wanted to "re-home" my current PC into another case.
Relevant hardware details:

Mainboard: AsRock x99 Extreme 4
GPU: Palit GTX 1080
PSU: BeQuiet Straight Power 10
Various SATA Devices: two optical drives, 2 spinning rust drives and 2 SSDs

Old Case: Aerocool DS 200
New Case: Fractal Design Define 7

Ordinarily, doing something like this is, while time consuming, should be a routine task. So i went ahead and fully disassembled the PC (I did not remove the CPU, RAM and NVMe boot drive)
and then started with Board and GPU in the new case. First boot attempt to see if it still turns on was successful, i got an image, but i could not boot. Knowing that the board has had issues with loosing the bootorder before, i went ahead and popped the BIOS battery out to fully reset the BIOS.

That was the point the issue started.

With removed battery, i reconnected the power, and tried turning it on again. No dice. Dead as a dodo, no LED, not even a twitch on any fan.
Anything i did afterwards hat no effect at all:

- putting the battery back
- removing everything except the CPU
- shorting the powerswitch contacts on the board to exclude a dead switch
- jumpered to the secondary BIOS
- "proper" BIOS reset with jumper to "Clear CMOS"

Nothing helped, the system was in all effects dead. I have to admit, i did not check voltages, except of the battery, which is still good.

Next, i removed the board from the case and repeated all tests. Still dead.
I then tried an old PSU that should still be good. Dead, even without the GPU inserted.

I essentially did everything i could think of, short of removing the CPU (i have currently no thermal compound on hand) and jumpstarting the PSU.

The kicker though: As a last act of desperation, i put everything back into the original case. And on the first effin try, the thing booted back up as if nothing has happened. That was now more than two weeks ago, and the PC still runs rock solid back in it's old case.

While the system is running now, i still have absolutly not idea *why* the rehoming failed so spectacularly.

I double and tripple checked the mainboard standoffs in the new case, to make absolutely sure that i had them at the correct locations, before the first power up. I checked them again after the power issue started. There is only one difference: one of the standoffs in the new case is not for a screw, but is a small stud fitting into the hole on the mainboard. A neat idea, since if you have a large CPU cooler mounted, that mounting hole can become inaccessible. The stud fits exactly into the mainboard mounting hole. I would think that a short caused by a incorrectly mounted standoff would cause permanent damage anyway.
But could the lack of a screw at that point have caused the issue? Something caused by the lack of a solid ground/common connection at that location?
I also know of the reports of AsRock boards dieing when the power is removed. But that are other series, and when not in use, my PC is fully turned off every day via a switchable power strip, and never showed any power issues in the four years i now have it. And the system is now running again.

Currently i am reluctant to do more tests and repeat the whole procedure. Spareparts are expensive for that socket, and adequate new parts are still very expensive due to various shortages. But i still can't stop thinking about this. The PC will go as a gift to my nephew as soon as i have new parts, but i'm afraid of lingering issues.

TL;DR: What could be the reason why a PC runs in one case, but not in an other?

[MK14]

In the new case, any of the following, could be faulty (e.g. shorted out), hence making the power supply refuse (quite correctly), to allow the system to start.
Or plugged in, wrong. (Sorry).

The things you plugged in, which were part of the new case.

I.e./e.g. Fans, USB extenders, etc ?

Especially the ones which can/do use power.

Less likely the large I/O connectors (with Leds, switches) etc.

What about the power switch on the new case ?
Did anything happen (even slightly), when you pressed it ?
Did you try starting the PSU, without using the switch (internet search supplies method, basically short 2 wires) ?

There are probably other possibilities.

[MK14]

Also, you shouldn't be running it, or ever powering it up, WITHOUT the CMOS battery connected and working.
Removing the battery with the power off, to clear the CMOS is fine, as is pressing a CMOS clear switch (if your motherboard has one).

Maybe you can power it up without a battery (I'm NOT 100% sure), but it sounds wrong/risky to me, without a battery, before it is first powered.

EDIT: Also, you DID try some of what I said in the first post, already, so my apologies. But I preferred the list to be comprehensive, anyway.

[Ranayna]

On the first working try, i had most front connectors connected: power and reset buttons, power and HDD LEDs, and Front USB and Audio as well. Case fans were not connected on the first attempt, and never afterwards.
When the issues started, i disconnected everything. I also switched reset and power buttons and buzzed them both, to see if one of them might be broken.
I checked the IO shield for shorts as well, i know that it can quickly happen that a spring contact slips *into* an USB port.

My lasts tests were done with the board on a cardboard box, PSU next to it on the table, with CPU installed and CPU fan and power supply (both 24pin and 8pin connectors) connected, but *nothing else*. I tried starting by shorting the pw switch contacts on the board with a screwdriver. I have not tried starting the PSU directly.

For all tests there was no flashing of any LED or any twitch of any fan, no movement at all. Only one thing now comes back to mind, which i found odd, and that prompted me to try my old power supply: When plugging the IEC cable into the supply, there was always a significant crackle of large inrush. That happened both within the case and also with minimal configuration on the bench, but stopped after reassembling within the old case. But at no point i tripped a breaker or GFCI.
I don't fully remember, if during the bench tests the PSU was still in the mounting frame of the new case. I had it lying on the bench, but i don't remember if i removed the frame or not. A possible point of investigation, but the other PSU never had the frame.
Additionally, i also took a longer break before i reassembled the components back into the old case, but i do not remember if i had the power connected during the break or not. That could also have cleared lingering issues.
Your point sounds plausible: *Something* tripped some internal protection of the PSU, but apparently did no obvious permanent damage.

[MK14]

First boot attempt to see if it still turns on was successful, i got an image, but i could not boot. Knowing that the board has had issues with loosing the bootorder before, i went ahead and popped the BIOS battery out to fully reset the BIOS.

That was the point the issue started.

With removed battery, i reconnected the power, and tried turning it on again. No dice. Dead as a dodo, no LED, not even a twitch on any fan.

Reading comprehension error on my part. I seemed to miss that part.

So it could be the motherboard was playing up. E.g. Unhappy with the cpu fan speed or something, looking for missing disk drives, etc. Then not completing the boot up process ?

The new case, seems to include a complicated fan controller board. Quick read of manual.
https://www.fractal-design.com/wp-content/uploads/2020/02/Define_7_Manual-V2.pdf

[MK14]

When plugging the IEC cable into the supply, there was always a significant crackle of large inrush. That happened both within the case and also with minimal configuration on the bench, but stopped after reassembling within the old case.

That reminds me, when I had a similar problem, on a past/old computer. The huge current the GPU + everything else needed, meant that if the power cord and/or internal plugs were not perfectly seated. The computer could exhibit the same symptoms as your computer.
Plugging in (re-seating) everything power related (mains lead and the PSU output leads), reasonably hard, solved the problem.
Possibly try another power lead and/or mains socket.

Another thing that comes to mind, is that computers have become fussier. There can be additional psu leads that need to be plugged in, otherwise the computer may well refuse to boot up.
I.e. On the GPU and motherboard (for the cpu).

[Ranayna]

Yes, the Define 7 has some kind of fan controller hub. That is supposed to be connected to the PSU with a SATA power connector, and one connection of that hub goes to the mainboard for PWM control, and the internal fans are all connected to that hub.
I did not have this connected yet, mainly because i was not sure to which port on the mainboard it should go. I figured that in the worst case i would run the pc without the side panel while researching the way it should be connected.

I actually was not aware that i can be a bigger issue to start without installed BIOS battery. I removed it, and tried to start, yes. I only put it back in after a couple of tests, i am not sure exactly when, but the bench tests were done with battery installed. All bench tests, and the first successfull test back in the old case, where done without GPU. I just wanted to see at least an LED light up on the board and see CPU and PSU fans spin... Which only happened back in the old case.

The AsRock board, from the get go, was always fussy with the M.2 slot. The original M.2 SATA SDD i had in that slot was sometimes simply lost, and the PC just stated a missing boot device or even got stuck without error somewhere in POST. A power cycle always fixed that.
The M.2 NVMe drive that i am using now (installed around a year ago) is not even showing up in the BIOS, (M.2 slot is shown as empty) but works fine as boot device anyway. 
So the board is not without issues, for sure.

For now my conclusion is that i will not be doing anything major to the current hardware, until i have new hardware. It was a crappy situation, to have a major issue two days before christmas, with all non essential shops closed due to lockdown
When i have new stuff i will take time, together with my nephew, to troubleshoot again.

[tunk]

Just a guess - a bad solder joint or contact somewhere on
the motherboard, and when installed in the old case there's
a flex in the motherboard that closes it.

[MK14]

For now my conclusion is that i will not be doing anything major to the current hardware, until i have new hardware. It was a crappy situation, to have a major issue two days before christmas, with all non essential shops closed due to lockdown
When i have new stuff i will take time, together with my nephew, to troubleshoot again.

That makes sense 

When something new comes out (e.g. DDR5 memory, eventually), one is likely to have only one set available (DDR5). So, if it doesn't work, you can't swap it with anything, to try and find out what has failed.
I.e. Without known working stuff to swap with, it makes it considerably more difficult, to sort out.

Motherboard boot issues, can be a frustrating pain in the neck to deal with, I share your frustration. 
M2 drives are quite well known to potentially have/cause boot up problems.

I think you have been doing the right things (except maybe the CMOS battery, which you already noted).

[CJay]

Also, you shouldn't be running it, or ever powering it up, WITHOUT the CMOS battery connected and working.
Removing the battery with the power off, to clear the CMOS is fine, as is pressing a CMOS clear switch (if your motherboard has one).

Maybe you can power it up without a battery (I'm NOT 100% sure), but it sounds wrong/risky to me, without a battery, before it is first powered.

EDIT: Also, you DID try some of what I said in the first post, already, so my apologies. But I preferred the list to be comprehensive, anyway.

Nah, you can run them with no battery, no problem at all.

Most common problem I've run into where components work in one chassis and not another is an extra mounting pillar or earthing spring.

[Ranayna]

I have double-, triple-, and finally even quadruplechecked the number and locations of the standoffs
There are not too many, and not too few, the doubly counted amount of screws matched the standoff count (one screw less since one of the standoffs is a stud)
The spring contacts on the IO shield are fine as well, i checked them before the first power up, to make sure they haven't slipped into a USB port. Also nothing was bent on the IO shield after i removed the board again, and the IO shield was not attached during the bench tests anyway. I never needed any excessive force to insert or remove the mainboard.
There are no cables running between the mainboard and the tray, on either the old or the new case, so no possible cables with pierced insulation (been there, done that, 10 years ago )

Those are the things i am 100% sure that i got correct. But i know that standoffs can be an issue, that is why i still suspect that single standoff that is just a stud, instead of a proper one with a screwhole. If the standoffs or grounding springs are an issue, it was the lack of proper connection.

[nightfire]

Additionally, i also took a longer break before i reassembled the components back into the old case, but i do not remember if i had the power connected during the break or not. That could also have cleared lingering issues.
Your point sounds plausible: *Something* tripped some internal protection of the PSU, but apparently did no obvious permanent damage.

Good PSU have self-resetting protection devices that reset themselves when the power is unplugged for some time, usually 1 Minute is quite sufficient.
Those protection is against overcurrent, voltage surges or drops etc.
Some good quality manufacturers (I am a Seasonic fanboy, BTW) also document quite well which protection modes they have implemented.