I have bought a new Raspberry Pi 4 and while troubleshooting connection to a DAC module I measured the voltage at 3.3V power pins. With reference to the pin header number as shown on the diagram below, the pins I tested are:
pin-1 (3V3) & pin-6 (GND) pin-17 (3V3) & pin-39 (GND)
I am using the official R-Pi supply and I measured strange voltages at 3.3V pins. Mostly it was 5.14V and sometimes it was < 1V. This is without any external peripheral connected to the Pi. I am using a Fluke 117 DMM and I checked it against a known 3.3V source to confirm it was working properly.
I don't think this is normal? Is it?
The pi itself boots up and works fine. What could be causing this?
I have read about under voltage warnings but since I am running it in headless config so how can I check if Pi indeed is having low voltage issues?