b450 pro 4 Sometimes won't turn on

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   i am using a b450 pro4 since January 2020.
Config:
Amd ryzen 5 3400g
Asrock b450 pro 4
ADATA XPG Gammix 8GB X 2
Crucial MX500 256gb 
Crucial BX500 500gb
wd blue 2tb
wd blue 4tb
Corsair cx450
Corsair carbide spic delta

APC BX600i UPS

from 03/08/2025, the computer switches on sometimes and sometimes it doesn't (for many days). 
if it doesn't, i leave the ups on. it might switch on after 15-20 minutes or even after 5-8 hours.
when it starts after this dead episode, it shows an incorrect time (some 2-3 hours after it was switched off) e.g. i turn off the computer at 10:30pm then when it gets switch on, it might show time as 12.44AM next day. cmos battery is new, installed just a month back.

3 days back (after a 10days dead episode), it was disassembled, new thermal paste applied and reassembled. it worked that day. next day i tried in the evening but it didn't work. yesterday it started after an hour and worked.
i tried a different working psu as well when it was not working but it did not switch on then too.
removed ram sticks and it didn't switch on.
removed all peripherals / HDD / SSD and it doesn't switch on many times.

when it gets switch on, it works fine like today it is working for some 8 hours without any issue.
no one in the city has any idea why it doesn't switch on sometimes. i have consulted a lot of people who provide service and even a gold medalist electronic engineer. i have tried various tech forums but no one has any idea except checking motherboard and processor with different working ones which people say can be done in the official service centre.

The most surprising thing is that it charges my digital watch from the front panel usb port when it doesn't start (cpu / cabinet fans doesn't start).

another issue i noticed since day before yesterday that when i am working on facebook, if a click on any image to open it, it shows a light black rectangle sort which flickers for a second and then shows the image. 

i am ready to replace the part which is faulty but have no idea which one has any issue. i wanted to get the motherboard checked if there is any method in service centre to make sure that there is some fault in the motherboard so that i can get it replaced if it is faulty.

what could be the problem in it?

i have sent asrock support an email for the details of service centre in my city on 11/08/2025 but they have not replied till now.
i have seen the details on asrock website and tried to call on that number but it was not answered.
i have looked for the details of that company that provides service and called on their other number, they confirmed tha they are the same company but replied that WE DON'T DEAL IN COMOPUTER.

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manushya Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 01 Mar 2025 Status: Offline Points: 65	Post Options Post Reply Quote manushya Report Post Thanks(0) Quote Reply Topic: b450 pro 4 Sometimes won't turn on Posted: 8 hours 45 minutes ago at 8:49pm
	i am using a b450 pro4 since January 2020. Config: Amd ryzen 5 3400g Asrock b450 pro 4 ADATA XPG Gammix 8GB X 2 Crucial MX500 256gb Crucial BX500 500gb wd blue 2tb wd blue 4tb Corsair cx450 Corsair carbide spic delta APC BX600i UPS from 03/08/2025, the computer switches on sometimes and sometimes it doesn't (for many days). if it doesn't, i leave the ups on. it might switch on after 15-20 minutes or even after 5-8 hours. when it starts after this dead episode, it shows an incorrect time (some 2-3 hours after it was switched off) e.g. i turn off the computer at 10:30pm then when it gets switch on, it might show time as 12.44AM next day. cmos battery is new, installed just a month back. 3 days back (after a 10days dead episode), it was disassembled, new thermal paste applied and reassembled. it worked that day. next day i tried in the evening but it didn't work. yesterday it started after an hour and worked. i tried a different working psu as well when it was not working but it did not switch on then too. removed ram sticks and it didn't switch on. removed all peripherals / HDD / SSD and it doesn't switch on many times. when it gets switch on, it works fine like today it is working for some 8 hours without any issue. no one in the city has any idea why it doesn't switch on sometimes. i have consulted a lot of people who provide service and even a gold medalist electronic engineer. i have tried various tech forums but no one has any idea except checking motherboard and processor with different working ones which people say can be done in the official service centre. The most surprising thing is that it charges my digital watch from the front panel usb port when it doesn't start (cpu / cabinet fans doesn't start). another issue i noticed since day before yesterday that when i am working on facebook, if a click on any image to open it, it shows a light black rectangle sort which flickers for a second and then shows the image. i am ready to replace the part which is faulty but have no idea which one has any issue. i wanted to get the motherboard checked if there is any method in service centre to make sure that there is some fault in the motherboard so that i can get it replaced if it is faulty. what could be the problem in it? i have sent asrock support an email for the details of service centre in my city on 11/08/2025 but they have not replied till now. i have seen the details on asrock website and tried to call on that number but it was not answered. i have looked for the details of that company that provides service and called on their other number, they confirmed tha they are the same company but replied that WE DON'T DEAL IN COMOPUTER.

Xaltar Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: 16 May 2015 Location: Europe Status: Offline Points: 28988	Post Options Post Reply Quote Xaltar Report Post Thanks(0) Quote Reply Posted: 5 hours 42 minutes ago at 11:52pm
	That is a bit of a headscratcher but, aside from the possibility that you may have 2 marginal/defective PSUs on hand (possible) there may be a clue in the image viewing glitch you mentioned. There is a chance the CPU may be faulty and not detecting some of the time. If memory serves, the board will not power up without a CPU installed, it will behave exactly as you describe, pressing the power button does nothing but devices will still charge from USB. The only way to test this would be with a spare CPU. Now it is possible it could be the board, or the board doesn't like both of the PSUs you tested but based on what you describe, I feel the CPU is the next item that needs to be ruled out. This is trusting that the second PSU you tested with was a properly functioning unit. My first instinct with intermittent power issues is always PSU but let's rule that out for now. Edited by Xaltar - 5 hours 38 minutes ago at 11:56pm


manushya Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 01 Mar 2025 Status: Offline Points: 65	Post Options Post Reply Quote manushya Report Post Thanks(0) Quote Reply Posted: 4 hours 34 minutes ago at 1:00am
	as far as i remember, the image viewing glitch only started after the disassemble - reassemble thing 3 days back. the second psu was a corsair vs350 which was given to be by a local computer service person from his own computer which i have returned and his system is working as always so i think that the psu is not the culprit. i will try to visit compuworld, the service provider mentioned on asrock website to see what they have to say on this. whatever is changed to check, need to be there for 3-4 days to see if that works and that particular part is the culprit. is there any other software / hardware with the service centre using which they can diagnose if the motherboard is all right or not? thanks mate.