System refused to start until I unplugged a USB cable

[TudorF]

Weird thing happened: I used my PC as usual the previous day, I charged my phone using a USB-C cable plugged in the computer, when it finished charging I unplugged the phone from the cable but left the cable plugged in the system. Then later I shut the system down.

Next morning, when I pushed the Power button it wasn't starting. Kept pushing, nothing.

Then I thought I should try something, so I unplugged the USB-C cable and when I did I saw a quick flashing LED on the mobo, which is how the mobo signals power just got in the system when you plug it.

After that, it started normally.

 

What caused this and should I be worried about the power source? For a moment, I thought it was busted.

[DoctorNick]

3 hours ago, TudorF said:

Weird thing happened: I used my PC as usual the previous day, I charged my phone using a USB-C cable plugged in the computer, when it finished charging I unplugged the phone from the cable but left the cable plugged in the system. Then later I shut the system down.

Next morning, when I pushed the Power button it wasn't starting. Kept pushing, nothing.

Then I thought I should try something, so I unplugged the USB-C cable and when I did I saw a quick flashing LED on the mobo, which is how the mobo signals power just got in the system when you plug it.

After that, it started normally.

 

What caused this and should I be worried about the power source? For a moment, I thought it was busted.

What is the specs on the PC? Might be a bad USB-c cable. Try charging using a different cable and observe if the same thing is happening

[TudorF]

@DoctorNick

 

Computer:      GIGABYTE B560M AORUS ELITE
CPU:           Intel Core i5-11500 (Rocket Lake-S, B0)
               2700 MHz (27.00x100.0) @ 4588 MHz (46.00x99.8)
Motherboard:   GIGABYTE B560M AORUS ELITE
PSU:		   Seasonic FOCUS GX Series GX-550, 550W
BIOS:          F1, 01/20/2021
Chipset:       Intel B560 (Rocket Lake PCH-H)
Memory:        16384 MBytes, ?-???
               - 8192 MB PC17000 DDR4 SDRAM - G Skill F4-3200C16-8GIS
               - 8192 MB PC17000 DDR4 SDRAM - G Skill F4-3200C16-8GIS
Graphics:      NVIDIA GeForce GTX 1650 (TU117-300) [ASUS]
               NVIDIA GeForce GTX 1650, 4096 MB GDDR6 SDRAM
Graphics:      Intel Rocket Lake-S GT1 - Integrated Graphics [B0] [GIGABYTE]
               Intel UHD Graphics 750, 1024 MB 
Drive:         WDC WDS500G2B0C-00PXH0, 488.4 GB, NVMe
Drive:         INTEL SSDSC2KW240H6, 234.4 GB, Serial ATA 6Gb/s @ 6Gb/s
Drive:         APPLE HDD HTS545050A7E362, 488.4 GB, Serial ATA 3Gb/s @ 3Gb/s
Sound:         Intel Tiger Lake PCH-H - cAVS (Audio, Voice, Speech) [B1]
Sound:         NVIDIA, Device ID: 10FA
Network:       RealTek Semiconductor RTL8125 Gaming 2.5GbE Family Ethernet Controller
OS:            Microsoft Windows 10 Enterprise (x64) Build 18363.2274 (1909/November 2019 Update)

The cable is some generic USB-C/USB-C one that came with a charger. Don't know what's the rating on it in terms of power delivery or data transfer.

For now, I just unplugged it and all works fine.

Will probably have to get a capable charger with a better quality cable and stop using it on the PC. There hasn't been any issue until now and don't remember doing anything unusual when I last charged the phone.
 

[KidKid]

19 hours ago, TudorF said:

Weird thing happened: I used my PC as usual the previous day, I charged my phone using a USB-C cable plugged in the computer, when it finished charging I unplugged the phone from the cable but left the cable plugged in the system. Then later I shut the system down.

Next morning, when I pushed the Power button it wasn't starting. Kept pushing, nothing.

Then I thought I should try something, so I unplugged the USB-C cable and when I did I saw a quick flashing LED on the mobo, which is how the mobo signals power just got in the system when you plug it.

After that, it started normally.

 

What caused this and should I be worried about the power source? For a moment, I thought it was busted.

What is plugged into the PC, or in other words, what is the USBC device? If it uses a lot of power, that may be the problem on its own.

[TudorF]

9 hours ago, KidKid said:

What is plugged into the PC, or in other words, what is the USBC device? If it uses a lot of power, that may be the problem on its own.

There was no device plugged in when I tried to start the system. I had the USB-C cable plugged in because, the previous day, I used it to charge my phone. And then left it plugged in the PC. And the next day the PC didn't start when I pushed the power button. Only started after I unplugged the USB-C cable.

[DoranVuTye]

Was it USB-C from mobo rear IO or USB-C from a daughterboard that goes to front case from a connector on the mobo?

From what it sounds like, I would guess some sort of short/fault protection. Like somehow 5v rail found route to ground and protection somewhere in the system kicked in.

Somewhat similar case.

 

[TudorF]

7 hours ago, DoranVuTye said:

Was it USB-C from mobo rear IO or USB-C from a daughterboard that goes to front case from a connector on the mobo?

From what it sounds like, I would guess some sort of short/fault protection. Like somehow 5v rail found route to ground and protection somewhere in the system kicked in.

Somewhat similar case.

 

USB-C from mobo back panel, yes.

The one under the HDMI port.

 

Quote

Like somehow 5v rail found route to ground and protection somewhere in the system kicked in.

That's what I suspected. And that's why I asked if this should be a cause for concern. Could de PSU get damaged by this?

[Blue4130]

14 hours ago, TudorF said:

USB-C from mobo back panel, yes.

 

The one under the HDMI port.

 

That's what I suspected. And that's why I asked if this should be a cause for concern. Could de PSU get damaged by this?

I would be more worried about the motherboard getting damaged than the PSU. If it was me, I wouldn't charge my phone on the computer in the future. It may be fine, but not worth the risk.