Question New MoBo and power supply. PC wont post after shutting off.

Sep 4, 2021
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Mobo: Asus ROG Strix B450-F Gaming
CPU: Ryzen 5 3600x
DRAM: Corsair Vengeance LPX 2x8gb 3200
GPU: Gigabyte Radeon RX 5700 XT
PSU: EVGA 700BR
SSD: Samsung 970 Evo
HDD: Seagate Barracuda 2TB
Case: Lian Li Lancool II Mesh RGB

I had to replace the mobo due to a usb short. Originally had an Asus Prime B450 Plus. After moving everything over to the Strix and starting it up, PC runs fine. No error LEDs during post. After initial start-up, PC runs fine. I played a games for a few hours yesterday with no issues. I shutdown PC properly and went to bed. When I tried to turn it on today it wouldn't post. If I reseat everything, I can get it to post doing a bench test. I also replaced the CMOS battery just in case. Any help or guesses why it won't post after turning it off?
 

DSzymborski

Titan
Moderator
Wait, did you upgrade to an EVGA 700 BR? And for what reason did you replace the old PSU? If the PSU wasn't the problem before, you've added a new variable into the mix; this is a mediocre PSU that isn't particularly well-suited for a very power-hungry/spiky GPU. And if this is the new PSU, what is the old PSU? And how did you determine the cause of the USB short or that it was the problem? The fuller the info on the specs and history of the problem, the better an answer someone can provide.
 

Lutfij

Titan
Moderator
Welcome to the forums, newcomer!

When you shut down the system, do you make sure that the rocker switch on the wall outlet is turned off? As for resetting, if the system operates fine after a CMOS reset, then it's very likely that the case might be shorting with your motherboard or you may be having a grounding issue. Here's what you can do next time the issue of not booting takes place. First, disconnect from the wall and monitor, don't remove the CMOS battery not short the pins on the CMOS jumper, instead just press and hold down the power button on the case for 30 seconds. After that, reconnect to the wall outlet and display and see if you can power up to OS GUI.

If the latter works for you, you're suffering from a grounding issue. Best call an electrician and scope out the wiring in your house/room where the system is operating.
 
Sep 4, 2021
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10
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Welcome to the forums, newcomer!

When you shut down the system, do you make sure that the rocker switch on the wall outlet is turned off? As for resetting, if the system operates fine after a CMOS reset, then it's very likely that the case might be shorting with your motherboard or you may be having a grounding issue. Here's what you can do next time the issue of not booting takes place. First, disconnect from the wall and monitor, don't remove the CMOS battery not short the pins on the CMOS jumper, instead just press and hold down the power button on the case for 30 seconds. After that, reconnect to the wall outlet and display and see if you can power up to OS GUI.

If the latter works for you, you're suffering from a grounding issue. Best call an electrician and scope out the wiring in your house/room where the system is operating.
@Lutf
The wall outlet doesn't have a switch, unless you mean the PSU switch. If that's the case, yes I made sure everything was plugged in properly and PSU was switched on. I also have a Corsair CXM 650W that I tried. That was the original PSU and I did a bare bones bench test with that as well and got the same issue.

I did find out that if I jump the CMOS then jump the power switch pins, it will post fine everytime with both PSUs. I'm going to try reassembling everything and do what you said with the case power button. I'll let you know how it goes.
 
Sep 4, 2021
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10
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Wait, did you upgrade to an EVGA 700 BR? And for what reason did you replace the old PSU? If the PSU wasn't the problem before, you've added a new variable into the mix; this is a mediocre PSU that isn't particularly well-suited for a very power-hungry/spiky GPU. And if this is the new PSU, what is the old PSU? And how did you determine the cause of the USB short or that it was the problem? The fuller the info on the specs and history of the problem, the better an answer someone can provide.
I upgraded to the EVGA 700BR because the local pc store thought PSU might have been the issue. I wasn't able to get it to post with the old PSU, Corsair CXM 650W, yesterday but I got it to post today. I've tested both PSUs and the both work and will get pc to post.

USB short was determined by attempting to get PC to post with the old MoBo, Asus Prime B450 Plus, and the Corsair PSU. I ran a bare bones bench test and PC posted but with the error message "USB device over current status detected!! System will shutdown after 15 secs."
 
Sep 4, 2021
5
0
10
0
Welcome to the forums, newcomer!

When you shut down the system, do you make sure that the rocker switch on the wall outlet is turned off? As for resetting, if the system operates fine after a CMOS reset, then it's very likely that the case might be shorting with your motherboard or you may be having a grounding issue. Here's what you can do next time the issue of not booting takes place. First, disconnect from the wall and monitor, don't remove the CMOS battery not short the pins on the CMOS jumper, instead just press and hold down the power button on the case for 30 seconds. After that, reconnect to the wall outlet and display and see if you can power up to OS GUI.

If the latter works for you, you're suffering from a grounding issue. Best call an electrician and scope out the wiring in your house/room where the system is operating.
I did what you said and still wouldn't post. After that I turned off the PSU via the switch, jumped the CMOS, turned the PSU back on and then turned the PC on via the front panel button. It took me back to bios and all my changes were saved so I exited and let it boot. Could it be a faulty front panel button? I'd rather not have to jump the CMOS every time I want to use my PC.

Also, I can leave it in standby or restart it from the start menu with no issues. It's only when I shutdown completely that causes the problem.

EDIT: I disconnected the power switch cable to see if I could jump the front panel button pins after a shutdown. It failed. So far the only way I can get it running again is by jumping the CMOS after a shutdown.
 
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Sep 4, 2021
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To anyone who has similar issues and can't figure it out after trying everything else. It's probably a bad mobo. I replaced my ROG Strix b450-f with a MSI B550 gaming plus and haven't had any issues since.
 

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