Yes, it is plugged into the t_u2t.
It still doesn't have any LEDs anymore - how can I reset it? Have to say the t-u2t is very confusing.. only noticed the button hours in .. still not sure what it does.
Should the status led be on when just connected to power? - mine doesn't.
Could it be broken?
@dirk Well, Dirk that sketch has 'a lot of moving parts'!
My troubleshooting approach is run my HotHead sketch and see if it will run on battery.
If 'yes' then we must assume that one of your many sensors are drawing too much current and lowering the Vinput.
Can you measure the battery voltage with a meter as you unplug the USB and switch to battery. (This may require a push of the little black Reset button to restart it.
LilyGO sells these as a ready-made user device with a firmware uploaded to it, rather less than a typical Arduino experimenter kit!
Hard to find the original as-shipped source code for Arduino 2.x.x
Hard to "nail-down" the LilyGO GitHub repository for your EXACT board
Sure you can create your own program, but converting back to as-shipped might be difficult due to ever-shifting libraries and other 'dependancies'
(This third party firmware repository may help: https://github.com/lyusupov/SoftRF/wiki/Prime-Edition-MkIII?spm=a2g0o.detail.1000023.1.4d0d23a04K7ZhM