Raspberry Pi 4 Under Voltage Warning

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outdoorsnz

674 posts

Ultimate Geek

#283907 19-Mar-2021 10:13

I have been running my Raspberry Pi 4 8gb with USB SSD boot, overclocked settings of arm_freq=2100, gpu_freq=750 and over_voltage=6. And have the raspberry pi fan installed and set to come on at 70 degs.

This has all been working fine for quite some time.

But in the last week or so, the yellow lightning bolt - under voltage warning has been coming on quite a lot. Not constantly or at idle conditions, generally under load conditions such as opening new web pages and booting.

Have now turned off overclocking and hasn't made any differences.

Apart from firmware / system updates, nothing else has changed. Never saw this prior to a week ago. SSD and logitech USB keyboard dongle are the only USB devices connected.

Using official raspberry pi 3A USB C power supply.

Could this be a failing power supply, result of overclocking or simply a update in the firmware that wasn't warning of under voltage?

outdoorsnz

674 posts

Ultimate Geek

#2677112 19-Mar-2021 11:38

Update! I found the source of this issue. Turns out the Logitech K260 USB dongle was causing the voltage drop. I chanced on a google search result that talked about USB cables causing voltage drops. So process of replacing all cables found the offending cable.

My question is now, can you buy generic wireless USB keyboard receivers? Think I recall seeing something on here about that.

SpartanVXL

1315 posts

Uber Geek

#2677141 19-Mar-2021 11:59

Theres another option to trying to see if you can find a custom replacement receiver.

Get one of those usb hubs with external power and run the receiver off that instead. The power will come from the hub rather than the Pi

outdoorsnz

674 posts

Ultimate Geek

#2677157 19-Mar-2021 12:20

SpartanVXL: Theres another option to trying to see if you can find a custom replacement receiver.

Get one of those usb hubs with external power and run the receiver off that instead. The power will come from the hub rather than the Pi

Yes I think you are right on getting a USB hub. Something must have changed with the firmware and voltage draw. So not a fault USB receiver.

Switched to a bluetooth keyboard and a usb mouse. No issues at all until you plug in another USB device and voltage warning back, so puts you over the limit.

Basically with voltage issues going on, temp and CPU were maxing out and running very crap!

frankv

5680 posts

Uber Geek

Lifetime subscriber

#2677202 19-Mar-2021 13:24

Another option: ditch the keyboard, mouse, and screen from the RPi and instead ssh -X into it from another Linux machine. PuTTY from a Windows machine will also do SSH -X I think to get a GUI?