I'm having an issue with the Bally Atlantis I just finished restoring (well, almost finished restoring). It plays perfectly and all the sounds are correct, except there's no voice. At first I suspected the sound roms, so I burned and verified new ones. No change, still no voice. Next, I noticed all boards matched (by serial number) except the sound board, which is a Williams D-11581. Bally used this Williams board on a few 6803 games (I'm guessing after they merged). The sound board in my game had Taxi written on it, so I suspect the previous owner replaced the original board with another D-11581 from a Taxi.
That's all fine, but then I noticed in the manual that a 55516 at U6 recreates Atlantis speech. I thought that was likely my issue and was going to test the chip. I looked at my board and saw that U6 wasn't even populated on my board! I searched through my supply of boards and found 2 more D-11581 boards. Guess what? Those boards were also missing U6.
I believe all my boards are earlier versions of D-11581, and later board revisions added and populated U6 with a 55516. I have a 55516 I found on an early Williams board, and can easily desolder it, add a socket to U6, and populate it. The issue is there are many more components missing on all 3 of my boards compared with pics I've found of D-11581's that are original in a Bally Atlantis.
I'm guessing others have run into this same issue, but I can't find it documented anywhere. Does anyone know what other components on earlier versions of this board need to be populated in order for the voice to work? I may end up populating everything that isn't on my board compared to the later revisions, but I'm guessing some components aren't necessary as the boards were also used in some Williams video games.
Anyway, I thought I'd give it a shot here first before I dig into this too much to try and get the voice to work. Since other components are not populated, I'm also thinking that just replacing U6 won't work (although it's possible it could). Of course, my theory could be wrong about all this and something else could be preventing the voice from working. If that's the case, I can find and start digging through the schematics before replacing any components.