PACHISLO SLOT MACHINE SOUND BOARD FOR OLYMPIA / HEIWA # C9906-04.  If you have no sound or sound issues, this is the board you need.  If your sound works fine but it is just TOO LOUD then see eBay item 284760352540 for volume controls.  This board works with MANY older Olympia / Heiwa machines including:

Atlantis Doom. Heiwa 2000

Battle Knight, Olympia 2000

Bee Kids Club, Olympia 2000

Gai Kids, Heiwa 1999

Hot Rod Queen, Olympia 2000

Lupin III, Heiwa 2000

Nangoku, Olympia 2001

Nice Day, Olympia 1999

Shark, Olympia 1999

Snowky, Heiwa 1999

Super Stardust, Olympia 1999

...and others.