I have just inherited an Alien Poker game (Williams, System 6) and am working to clean it up. The sound works most of the time when I start it up, but will turn off if I leave the game on for a while. I wiggle the power connections, and sometimes it will come back on. Where do I start to diagnose this? I am guessing it is heat related, but I am a noob with the process and am not entirely sure where to start. Thanks in advance!