On Sun, 03 Feb 2019 15:33:04 +0000, Markus Robert Kessler wrote:

> Hi,
>
> I just bought a Raspberry 3B+ and now I am setting it up.
>
> Nice little box and it's really fast in comparison to my other RPis like
> Zero/W, A, B... It's fun to work with it.
>
> But, besides this, one thing makes me really wonder:
>
> Upper right on the screen there appears a yellow flash all the time and
> one of the boot messages reads something like "undervoltage detected".
>
> The new box is working fine, though, but I connected a USB voltage
> measuring device and saw that the power input on micro USB connector of
> RPi3 never goes under 5.01 Volts, but, the USB power on those 4 USB port
> (I only checked 2 of them with identical results) is only 4,55V (!).
>
> Total input current is at 0.6 A in average, so I doubt that the 5V/2A
> power supply is too weak.
>
> Am I doing something wrong?
>
> Best regards,
>
> Markus

where are you measuring the 5.01V
at the PSU itself or on the PI
Cable resistance can easily cause a Voltage drop & many PSU's are of poor
quality & drop voltage even under light load.


--
A political man can have as his aim the realization of freedom,
but he has no means to realize it other than through violence.
  -- Jean Paul Sartre

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