Question PC dead, doesn't post but memory and power button leds on...

[spal23]

Hoping someone can get me pointed in the right direction with my PC issue.
This morning I started my PC as usual and launched all my apps as usual. No problems. It was on for a few hours. After coming back to it after doing stuff around the house I saw that it was "asleep" meaning the monitors were off but the power button light was on. I tried to wake it up by using the mouse at first. After that didn't work I used the keyboard. After a minute I realized I had a problem. So I tried to shut it down via the power button but no response. Then I just shut it the power on the back of the PSU then unplugged it and tried clearing any residual power in the system. After reconnecting the PSU I noticed the same thing was happening; no post and only the power button led on. So I opened her up and noticed the memory leds were the only components lighting up. I've never experienced something like this with a pc so I realized it could be any number of things but foremost I'm thinking the PSU is acting up but of course there is power going to the lights so I'm not sure about that one. I could be the mobo but again the mobo is the conduit for power from the PSU to the memory modules and the power button so I'm a little stumped.

Here are my specs.
About a year ago I repurposed an old ATX case and updated all the components. It as been running well ever since
Specs:
CPU - AMD Ryzen 7 3700X 3.6 GHz 8-Core Processor
CPU Cooler - Stock AMD
Motherboard - Asus TUF GAMING X570-PLUS (WI-FI) ATX AM4 Motherboard
Memory - G.Skill Trident Z Neo 32 GB (2 x 16 GB) DDR4-3200 CL16 Memory
Storage - Crucial MX500 2 TB 2.5" Solid State Drive
Storage - Western Digital SN750 250 GB M.2-2280 NVME Solid State Drive
Video Card - MSI GeForce GTX 1660 SUPER 6 GB VENTUS XS OC Video Card
Case - Cooler Master Centurion 534 ATX Mid Tower Case
Power Supply - SeaSonic FOCUS 750 W 80+ Platinum Certified Fully Modular ATX Power Supply
Operating System - Windows 10 Professional
Monitor - 2x HP, 2x Acer

The last component I added was the Seasonic PSU in June and it has worked well right off the bat.

Any advice would be appreciated. Thanks.

 

[Ralston18]

Power to the "lights" (LEDs) is not a true indication that all is well.

PSU's provide different voltages to different components. So a problem with one voltage (voltage rail) may "light up" some LEDs but the PC will not work.

Will the system boot into Safe Mode?

= = = =

Power down, unplug, open the case.

Clean out dust and debris.

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

Be sure to check case connections as well.

Look for signs of damage: bare conductor showing, melted insulation, browned or blackened components, pinched or kinked wires, etc..

Post accordingly.

 

[spal23]

Thanks for your reply. Yep looks like I will have to do some intensive troubleshooting.
Just a little more info... The PC will not power up at all and not post. However, when I plug the power back into the unit and switch on the PSU the fans and CPU do spin a little then stop until the power button is pressed for system startup. This is the normal behavior for this system, and probably most, so up until that point the system behaves like normal. What's different now is what I posted originally i.e. leds light up but that's it. Not sure if this info is helpful but can't hurt.

 

[spal23]

Ok so luckily I kept my last PSU, which worked fine prior to the Seasonic, so I reinstalled that one and yep the Seasonic was the problem. All other components look fine and work. Once I get in touch with Seasonic and figure out the root cause I'll update. Thanks.

 

[spal23]

Update - Seasonic is replacing the unit after seeing video of it not working. I have to say they were responsive, ~1 day. Customer service is good.