Question Troubleshoot me - inconsistent boot success

[EchoDelta]

Background:

So, I have just moved house, and my PC has been in storage for a few weeks. I also have a new monitor. These are the only 2 events that have occurred since my PC was booting normally. Oh, and I updated the chipset driver from 10.1.1.44 to 10.1.1.45 the other day but this issue was already happening.

MoBo: Strix Z270F, BIOS 1501
CPU: 6700k
PSU: HX850i
GPU: Strix R9 380 4GB
Monitor: XG27UCS (previously MG279Q)

How do I describe the issue...?
- No signal from monitor on ~90% of boot attempts (verified monitor power with OSD, autodetect input on/off yields no difference to success)
- Tried switching PSU off for some attempts, this doesn't seem to affect success of boot
- What does weirdly work is trying 5 minutes after giving up 😂 PC then proceeds to boot on demand, sometimes into safe mode (due to interrupted boot/shut down from multiple attempts) or I can get it into the BIOS
- Once proceeding out of safe mode or out of BIOS, PC loads absolutely fine into Windows
- The PC is then 100% usable for daily tasks and gaming with no issues whatsoever
- The issue reoccurs the next time I put the computer to sleep, or shut down

So yeah, I can't even get into the BIOS when this is happening, just straight no signal. No alarming LEDs on MB although for a brief period yesterday the "boot LED" was permanently lit (yellow), but on other attempts there have been no LEDs stuck on.

Any ideas? I'm so confused...

 

[Ralston18]

As I understand the described circumstances, my first thought is that something is loose. Takes some warming up to expand and tighten the connection. May have been jiggled loose during the move.

= = = =

Power down, unplug, open the case.

Clean out dust and debris.

Verify by sight and feel that all connectors, cards, RAM, jumpers, and case connections are fully and firmly in place.

Use a bright flashlight to inspect for signs of damage, loose or missing screws, cracks, moisture, corrosion, browned or blackened areas, swollen components. bare conductor showing, kinked or pinched wires....etc., etc..

Install a fresh new CMOS battery as a matter of elimination. Do so via the applicable motherboard's User Guide/Manual.

 

[EchoDelta]

Hello and many thanks for your reply!

I like your thinking and I have just unplugged the PC, dusted carefully inside and out, checked all cables firmly plugged on the frontside, removed the GPU, checked the CMOS battery was in properly (I don't have a spare to hand, will get one tomorrow if this issue persists), dusted the GPU, reinserted GPU and checked power cable inserted fully again, opened backside of case and checked PSU end of cables all in firmly.

Rebooted straight away, and I prompted a restart, which was flawless.

Admittedly guess we can't definitively call this a success yet - I'll need to let her sleep tonight and try again in the morning once everything is cold.

Will keep you in the loop...