find the reason of PC power off

Today i had powered on my PC, and it powered off few times, while power-on workflow. I had check in log, but didn't find the reason, I had powered it on about 14:00 or near, (few times until was successfully powered it on). The excidental power off was happened at the various moments: after system loaded and GRUB menu on screen or after password was entered and X-Window manager loaded, and old browser session restarted, or when new internet page started to open. Then it continued to work until now. in a listing below it show few lines after 14:13 boot, and few lines before the new boot in 14:19, it works about 6 min before exidental power-off so it may concluded the reasons, but i'm has not find error messages like : because of ... reason PC power-off or smth else. I had read man journalctl, just i don't know, what subject i need to find? **How to find the proper exidental power-off reason ?** Below i had listed the log from first power on today which has included all shorts periods in a start and normal workflow until evening > sudo journalctl -S "today" -U "17:00" ov 04 04:40:26 debian systemd: Reached target shutdown.target - System Shutdown. Nov 04 04:40:26 debian systemd: Reached target final.target - Late Shutdown Services. Nov 04 04:40:26 debian systemd: systemd-poweroff.service: Deactivated successfully. Nov 04 04:40:26 debian systemd: Finished systemd-poweroff.service - System Power Off. Nov 04 04:40:26 debian systemd: Reached target poweroff.target - System Power Off. Nov 04 04:40:26 debian systemd: Shutting down. Nov 04 04:40:26 debian systemd-shutdown: Syncing filesystems and block devices. Nov 04 04:40:26 debian systemd-shutdown: Sending SIGTERM to remaining processes... Nov 04 04:40:26 debian systemd-journald: Received SIGTERM from PID 1 (systemd-shutdow). Nov 04 04:40:26 debian systemd-journald: Journal stopped -- Boot 5e8abe8207f54af483786970a32bfdb1 -- Nov 04 14:13:53 debian kernel: microcode: microcode updated early to revision 0x22, date = 2022-0> Nov 04 14:13:53 debian kernel: Linux version 6.1.0-13-amd64 (debian-kernel@lists.debian.org) (gcc> Nov 04 14:13:53 debian kernel: Command line: BOOT_IMAGE=/boot/vmlinuz-6.1.0-13-amd64 root=UUID=a4> Nov 04 14:13:53 debian kernel: BIOS-provided physical RAM map: Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x0000000000000000-0x000000000009b3ff] usable Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x000000000009b400-0x000000000009ffff] reserved Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x0000000000100000-0x000000000fffffff] usable Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x0000000010000000-0x0000000012150fff] reserved Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x0000000012151000-0x00000000771abfff] usable Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x00000000771ac000-0x0000000079a73fff] reserved Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x0000000079a74000-0x0000000079aadfff] ACPI data Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x0000000079aae000-0x0000000079e7cfff] ACPI NVS Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x0000000079e7d000-0x000000007a23dfff] reserved Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x000000007a23e000-0x000000007aa2cfff] usable Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x000000007aa2d000-0x000000007aa2dfff] ACPI NVS Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x000000007aa2e000-0x000000007aa2ffff] reserved Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x000000007aa30000-0x000000007aae4fff] usable Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x000000007aae5000-0x000000007ab94fff] reserved Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x000000007ab95000-0x000000007affffff] usable Nov 04 14:13:53 debian kernel: BIOS-e820: [mem 0x000000007b000000-0x000000007fffffff] reserved Nov 04 14:13:53 d this is the lines before the next boot, so it's may be concluded the power-off reason, but i don't understand, which? There aren't any error messages ov 04 14:17:54 debian systemd: Finished systemd-remount-fs.service - Remount Root and Kernel > Nov 04 14:17:54 debian systemd: systemd-firstboot.service - First Boot Wizard was skipped beca> Nov 04 14:17:54 debian systemd: systemd-pstore.service - Platform Persistent Storage Archival > Nov 04 14:17:54 debian systemd: Starting systemd-random-seed.service - Load/Save Random Seed... Nov 04 14:17:54 debian systemd: Starting systemd-sysusers.service - Create System Users... Nov 04 14:17:54 debian kernel: lp: driver loaded but no devices found Nov 04 14:17:54 debian kernel: ppdev: user-space parallel port driver Nov 04 14:17:54 debian systemd: Finished systemd-random-seed.service - Load/Save Random Seed. Nov 04 14:17:54 debian systemd: first-boot-complete.target - First Boot Complete was skipped b> Nov 04 14:17:54 debian systemd: Finished systemd-modules-load.service - Load Kernel Modules. Nov 04 14:17:54 debian systemd: Starting systemd-sysctl.service - Apply Kernel Variables... Nov 04 14:17:54 debian systemd: Finished systemd-sysusers.service - Create System Users. Nov 04 14:17:54 debian systemd: Starting systemd-tmpfiles-setup-dev.service - Create Static De> Nov 04 14:17:54 debian systemd: Finished systemd-sysctl.service - Apply Kernel Variables. Nov 04 14:17:54 debian systemd-journald: Journal started Nov 04 14:17:54 debian systemd-journald: Runtime Journal (/run/log/journal/337f99dad83d4d2fb> Nov 04 14:17:53 debian systemd-modules-load: Inserted module 'lp' Nov 04 14:17:53 debian systemd-modules-load: Inserted module 'ppdev' Nov 04 14:17:53 debian systemd-modules-load: Inserted module 'parport_pc' Nov 04 14:17:54 debian systemd: Started systemd-journald.service - Journal Service. Nov 04 14:17:54 debian systemd: Starting systemd-journal-flush.service - Flush Journal to Pers> Nov 04 14:17:54 debian systemd: Finished systemd-tmpfiles-setup-dev.service - Create Static De> Nov 04 14:17:54 debian systemd: Starting systemd-udevd.service - Rule-based Manager for Device> Nov 04 14:17:54 debian systemd-journald: Time spent on flushing to /var/log/journal/337f99da> -- Boot 59ee50dd793649a3b9022074301768ee -- ov 04 14:19:07 debian kernel: microcode: microcode updated early to revision 0x22, date = 2022-0> Nov 04 14:19:07 debian kernel: Linux version 6.1.0-13-amd64 (debian-kernel@lists.debian.org) (gcc> Nov 04 14:19:07 debian kernel: Command line: BOOT_IMAGE=/boot/vmlinuz-6.1.0-13-amd64 root=UUID=a4> Nov 04 14:19:07 debian kernel: BIOS-provided physical RAM map: Nov 04 14:19:07 debian kernel: BIOS-e820: [mem 0x0000000000000000-0x000000000009b3ff] usable Nov 04 14:19:07 debian kernel: BIOS-e820: [mem 0x000000000009b400-0x000000000009ffff] reserved Nov 04 14:19:07 debian kernel: BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved Nov 04 14:19:07 debian kernel: BIOS-e820: [mem 0x0000000000100000-0x000000000fffffff] usable Nov 04 14:19:07 debian kernel: BIOS-e820: [mem 0x0000000010000000-0x0000000012150fff] reserved Nov 04 14:19:07 debian kernel: BIOS-e820: [mem 0x0000000012151000-0x00000000771abfff] usable Nov 04 14:19:07 debian kernel: BIOS-e820: [mem 0x00000000771ac000-0x0000000079a73fff] reserved Nov 04 14:19:07 debian kernel: BIOS-e820: [mem 0x0000000079a74000-0x0000000079aadfff] ACPI data BIOS Information Vendor: American Megatrends Inc. Version: 5.13 Release Date: 10/19/2020 Address: 0xF0000 Runtime Size: 64 kB ROM Size: 5 MB Characteristics: PCI is supported BIOS is upgradeable BIOS shadowing is allowed Boot from CD is supported Selectable boot is supported BIOS ROM is socketed EDD is supported 5.25"/1.2 MB floppy services are supported (int 13h) 3.5"/720 kB floppy services are supported (int 13h) 3.5"/2.88 MB floppy services are supported (int 13h) Print screen service is supported (int 5h) 8042 keyboard services are supported (int 9h) Serial services are supported (int 14h) Printer services are supported (int 17h) ACPI is supported USB legacy is supported BIOS boot specification is supported Targeted content distribution is supported UEFI is supported BIOS Revision: 5.13