3.3V & 5V output Measure ~.5v

I’m trying to use the 3.3v constant output on pin 23 off the 26 pin connector to drive an OLED, but I get ~400mv when I hook up that pin (not connected to anything) to the oscilloscope. I’m stumped. Does anyone know what could cause it?

Hey @levinemr - That is strange! I just verified 3.3V is present on pin 23 of the 26 pin connector. Take a look at this picture to confirm this is where you are measuring:

For reference, here is the page showing pinout:


I definitely checked the correct pins.

While trying to figure out what’s going on, the processor board started to overheat. It was to hot to touch. I unplugged it from the USB and the interface board, then plugged it back into to the USB port. It started to over heat immediately. I know the processor is running as it should, because I saw the leds flashing the blink program.

That’s the second one in three weeks. I must be accidently crossing some wires that shouldn’t be crossed. I was transitioning between 12v and USB power sporadically. In addition my power source is 13.8V (similar to a running vehicle).