Raspberry pi 3b undervolt problem

What is the problem?

Hi for some reason octopi always complains it's undervoltiing

What did you already try to solve it?

I have hard wired my pi (soldered wires direct to the pads on the bottom of the pi). Using a psu form a pc to power it. I even tested it with my bench psu slowly raised the voltage up to 5.5v and it was stil complaining.

Have you tried running in safe mode?

Yes

Did running in safe mode solve the problem?

No

Complete Logs

Will add logs if needed

Raspberry pi has heat sinks and a fan for cooling and was only drawing 350ma when hooked up to bench psu

Your pi detects the undervoltage - not octoprint.
Does your pi maybe backpower your printer via usb?

Sorry forgot to mention I've taped the 5v on the usb. So no back powering.

It's funny you should say that. If I put a different image on it it stops and works fine.

The undervoltage is reported by the vcgencmd utility which is part of raspbian aka Raspberry Pi OS on which Octopi is based on.
You can find further information to this utility here

Did you check the get_throttled status on a different image?

AHH ok that make sense. No didn't check the get_ throttled status on the other image.

I just don't understand. Yesterday it all worked perfectly done several prints of various lengths. But today had problem after problem with the dreaded lightning bolt :zap:. Pi kept crashing and stalling prints. How can it work flawles one day and be so bad the next?.

What type of power adapter do you use?

@Ewald_Ikemann asked what type but I'm just going to tell you that whatever you are using is marginal at best (i.e. will work one day and not the next) and should be replaced with a power supply that has at least 2.5A output (at 5V).

What you have is probably a charger, not a power supply. They may look the same but the circuitry inside is very different. Google for raspberry pi power supply and you will find multiple sources for what you need. This one from Amazon is a reasonable choice

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Hi I use a psu from a pc rated at 400w its a decent make and provides stable current and volts. But it has also been tested on a 5a bench psu that is also stable.

How are you connecting these PSUs to the Pi? If it is via the GPIO pins rather than USB C power in, then it is likely that the connectors for these pins are introducing resistance that is dropping the voltage. The standard jumper leads for GPIO don't make great connections with the pins.

Hi thanks for the reply. The power is connected via the pads on the bottom soldered on goodn solid connections. Using good sleeker wire.

The RPi hardware (or low level kernel software) decides if the power pleases it or not. If it doesn't like the power and you believe that the power you are supplying should be good enough, then maybe the hardware the RPi is using is failing. Only solution for that is a new RPi.