Those front panel indicators are 7-segment LED plus discrete LEDs. Brightness is modulated under control of the software as is information content. Do it wrong and you can burn the LEDs with too much current.
Ha! HA! HA!!!!
My Dad and I built one of those on the dining room table the summer of 1979!
After a month of soldering resistors like an Asian factory worker, we booted it up and those LED’s scrolled this epochal mesasge: “Your H8 is up and running”
We looked at each other and said “Is that it?”