Uncommon hardware with 4 CPU (Z80)! This is the one screen version of the game.
It doesn't start and displays only a plain black screen.
By passing my hand on a specific area of the board I could get it to boot on the title screen with missing elements but the game was stuck:
This is typical of a floating line somewhere. With my logic probe I found one of the address lines was cut (not visible, probably under an IC). I patched it with a piece of kynar wire but saw no improvement. The RAM @C14 is dead, I put a second hand one in place (I was running out of 6116 type wide at the time) and the game started but sound was absent:
I found another broken trace on one of the data lines of the audio RAM. I fixed it with another piece of wire and sound now works perfectly.