I am applying 5V to the pin J3 pin2 and GND to J3 pin6. The board does not power up.
When I read the voltage on those pins via multimeter I get 4.91V.
When I read voltage via multimeter on J2 pin1 and J3 pin6 I get 0V
when I power the board via USB-C it powers up and no problem communicating with the board.
When powered via USB-C I can read 3.3V but on 5V pins there is 0V.
Any ideas what is going on? I would really like to power these boards via 5V.
Thank you
How did you conclude that the board does not work?
Most importantly, the LEDs do not light up when powering the board over the 5V pins. So you cannot use the LED do determine whether it is running. You will need some other feedback (e.g. blink an LED through GPIO from your code) to check whether all is good.
good question. When I power the board via usb-c there is a red led, propably watchdog led, which flashes every so often. Secondly my code display text on e-paper that the board is starting and I can measure 3V3 on J2 pin1.
When I connect the 5V to the 5V pins none of above happens.
Resolution
5V pins are not connected in new version of the boards.
How I know
I got the email from Heltec support clarifying that on E290 boards the 5V pins has been removed and are not connected.
Wow… that’s wild. Way to go Heltec 
yep, it is a bummer as I have a few units for a project and now I need to modify mechanical part to fit extra USB-C breakout board and do hotfix for wiring to power these boards.
At least mystery is solved.