Space Encounters - distorted "trench"

[DavidVideo]

I recently acquired an old Space Encounters game. It plays fine, but the "trench" in the background of the screen is distorted. I have looked over the boards and don't see any signs of tampering, repair, or mods. The machine is old and crusty - but plays well. Any idea where I might track down this "trench" issue?

Also - I'm missing the color overlay. If anyone has one I'm interested. Otherwise, I'm going to purchase some of those "gel sheets" and attempt to make one myself.

 

[LyonsArcade]

Download the ram test program for space invaders (somebody may have made a Space Enounters one, too) and run it on the board, you may have a bad ram chip. If it hasn't been repaired, you DEFINITELY have a bad ram chip

You burn it on a rom, put it in the first slot, and it boots up and tells you which ram is bad.

 

[rg3]

Davidvideo did you ever figure out what was causing the distorted trench? My trench is completely missing.

 

[DavidVideo]

I was a bad chip on the daughter board.