That's the case when the display isn't initialized. There are several posts in this thread about flashing the ATmega. An Arduino works as programmer too
I will search back through the threads and see what I can find. If I can ever learn this I will post a YT video showing how.
Does the microcontroller (or anything else) get warm while the screen is on?
From the beginning. I picked the unit up to test a transistor one day. I noticed it did nothing. Screen did not come on and I did not feel any heat in the controller. The day before I had checked some HV caps. Was thinking that perhaps one was not discharged. I ordered a second unit.
Many months later I took the bad unit out and tried to read the controller. Then I tried writing the programs to it. But not knowing what I was doing may have corrupted the controller. Again I am a total noob at trying to do this. But after my failure I noticed that when I press the button I get a bar across the screen now. So it does show some sort of life. Perhaps it is toast. I am not sure.
I continued to play with it and this came up :
"BAT 4.8V empty"
I tried to program again and only get the “bar” now. I put it aside till I could learn more about it.