GuiLingKwek

An update. I had bought a brand new Geforce 1060... tadah! It only fixed my problem for 2 days (similar to when I changed my motherboard). I guess I've made a wrong diagnosis again. My god, this problem is persistent. Yesterday, I tried unplugging all my small peripherals (yes, at this point, I will need to doubt everything). My fans, my hard disks, SSD, optical drive. Then I discovered this... CPU fan plugged in = doesn't boot. Unplugged = boot. This was exactly what happened to my old graphics card! Why is it the fan now? Nonetheless, I changed a new fan. Nice and dandy. It boots! Today... it doesn't f**king boot again! CPU fan plugged in = doesn't boot. Unplugged = doesn't boot. I installed my old CPU fan = still doesn't boot. I gave up, went shopping. Came back = it boots, wIthout me doing anything more. Then something struck me. This problem usually appears in the afternoon. I have a habit of napping after lunch, then this will happen when I wake up. This is unlikely to be a problem with the power grid, I live in a city where electricity never gives trouble. (1 blackout event in over 30 years, What else could cause this in the afternoon? (it occurs at night as well, maybe not as often) I'll start keeping a diary on when and for how long this occurs. Another minor detail that I have observed. When I press the start button and it doesn't boot, my casing LED stays on but fans and the other parts of my computer doesn't. In that case, since I'm not able to start again, I will turn off the wall switch and turn it on. Subsequent attempts will not have the casing LED lit any longer than the fans. It has "memory" that it is screwed. Not sure if this provides any clues. Anyway, I have ran out of parts to replace. Just my PSU...

Corsair RM650i. I thought it could be the PSU faulty, but thought it was unlikely as the system do not shut down abruptly during operation. Let me share a little more information, 2 days before I experienced the first "Despair Mode". It's probably a coincidence so I did not share it initially. I was experiencing something similar, no POST. I tried removing my ram first, no help. I tried removing my GPU, no help. But when I removed my DVI-D cable from my GPU, the system magically starts. I couldn't believe it, the cable should have no impact on my system's ability to power up. I swapped the ends of the DVI-D cable (monitor <-> GPU), indeed, it's broken. System starts but display flickering. I bought a new cable, it was good... for 2 days. Subsequently, I removed my DVI-D cable to try starting my machine, it doesn't help anymore. So I thought it's a coincidence. I have figured out the real problem. It's my GPU. For the past few days, when I remove my GPU, I do not disconnect the power supply from my GPU. Thinking that it should behave like the other peripherals (that it'll receive power, just not detected by the system). But no, my GPU is causing the PSU to trip and shut down. Removing the 2 x 6 pin PCI-E from my GPU, the system is able to start. Resetting the BIOS probably extended the time taken to trip because the motherboard needed extra time to "freshen up" thus initializing the GPU later. Thanks all for the help, it's time to shop for Geforce 10 series <3 P.S. I wasted lots of time, effort, sweat, petrol (to replace my good, working motherboard. sorry Asus) and money (on a fresh tube of thermal paste) because I was too lazy to unplug the 2 x 6 pin PCI-E power supply.

An update. My motherboard was replaced on Friday. I took it home, set it up and it was working great. I was pleased. I checked that it has the latest BIOS. It was working fine this morning too. Unfortunately, it has entered the same "Despair Mode" now. A flash of power and off it goes. Diagnosing this problem is more difficult than expected. (No, there aren't any extra standoffs than necessary)

I have updated my BIOS. It was completed successfully, then it showed "System will reset now". It did reset and entered the "Despair Mode". I fiddled for a while and gave up. So I reset the BIOS. I got a big hint after that. System shut down without resetting bios is after about 0.3 seconds. However, if I reset bios, the system runs a little longer at 5 seconds. It shuts down either way, before any form of display could manifest. With this, I think it's fair to conclude that there's no need to test for short circuits. A hard bios reset wouldn't affect the time taken for a short circuit to occur. Maybe it'll work again later. My last option now is to RMA this motherboard.

Thanks for the suggestion. Even though this problem only surfaced for about 1 month (no problems for about half a year). I'll still give this a shot. The manufacturer had released 5 bios updates since then. I will post again after trying all the above.

I have not tried clearing cmos, because I don't think it's going to help. I thought long and hard and concluded it's not going to help. But maybe I'll try. Because I'm running out of options.

Besides, a short circuit is likely to cause problems even when the system is running right? I have not encountered anything unusual after the system is booted.

I thought of that and combed long and hard for things causing short circuits. I couldn't find anything in particular. I kept my system neat and tidy with cables managed. Besides, this issue is not recurring. There's no guarantee that the problem is fixed even if I managed to boot it outside the case.

A little about myself; I have been building my own systems for over 15 years. I don't do it to make money, so I do not have a bunch of spare parts lying around. This is my humble build. Asus H170M-Plus with 6700 (water cooled with a corsair AIO whatever model, I don't remember and i don't think it matters) 2 sticks of Kingston DDR4, 4GB An old GPU Palit Geforce 560SE (don't play games often) Corsair RM650i Fractal Design R5 Windows 10 I'm going to describe the problem now. This is unlike anything I've ever encountered, please bear with it. I experience No Power Up, when I push the power button, the LEDs lit for a fraction of a second, the fans spin for a quarter of a circle. That is all? No POST, nothing. I don't have a clue what's wrong. I started removing my GPU. Doesn't fix it. I tried moving/removing my RAM. That's not the problem. Sometimes, the system powers on! It is like a miracle if it happens. When I say miracle, I mean it. Today, it wouldn't power on. I went to sleep after an hour of tinkering and gave up. I woke up, all is good (Without doing anything other than pushing the power button). (Yes, I was tired of tinkering over these few days, when I was sleeping, I dreamt of posting in linustechtips for help, which is what I'm doing now) 2 days ago, I put it on the floor, it worked. I moved it up to my table, it wouldn't. It is so seemingly random. I tried shaking, pushing every connector to make sure they aren't loose, no, it didn't help. I read the sticky on No POST no Power up situation, it's all about reseating power cables and faulty PSU. It is unlikely my case as my system works fine (albeit sometimes!) I also realised this clue. When the system powers on, everything is flawless. It wouldn't power down by itself, it doesn't complain of abrupt shut down. It works perfectly fine. Sometimes I walk away, when I come back, it wouldn't turn on. Yes, I have NEVER seen this PC going into the "Despair mode" when I'm sitting at my desk. I probably shut it down, maybe sometimes I did not. I figured that it may be the power settings, I disabled sleep. It didn't fix the problem. What could be wrong? I figured maybe my motherboard needs RMA. Or maybe my PSU. Given that this issue do not recur for sure, I'm not sure I can get it replaced if it decides to work fine when I RMA. And I need to buy new thermal paste to reinstall my CPU, honestly, it's a pain. I would like to seek your opinions, fellow PC builders.

Can I have a NUC? Please...?