Whirlwind background music plays but no speech callouts
My Williams Whirlwind has a strange audio issue — the background music plays perfectly fine, but none of the speech callouts work. When the game calls out scores, warnings about the storm, or any voice clips, I get nothing. Sound effects like the bumper hits and slingshot sounds work fine too — it's only the speech that's missing.
I pulled up the sound test menu and tested different sound codes. The music tracks play, the sound effects play, but when I get to the speech ROM test range, nothing comes out. No static, no distortion — just silence where the speech should be.
The game is a System 11 board set. I haven't touched the sound boards since I got the game about a year ago. Is one of the sound ROMs bad?
yemons·3/21/2026★ 1 Answer
On Williams System 11 games like Whirlwind, speech and music/sound effects are handled by separate sections of the sound board. The speech is processed through a CVSD (Continuously Variable Slope Delta) codec chip and has its own speech ROM(s) and amplifier section. The fact that music and effects work but speech doesn't tells you the issue is isolated to the speech subsystem.
The most likely cause is a failed speech ROM chip or the HC55536 CVSD decoder chip on the sound board. Start by pulling the sound board and inspecting the speech ROM(s) — on Whirlwind, the speech data is on a separate ROM chip (U22 area on the sound board). Look for any corrosion on the IC legs, especially if there was any battery damage nearby. Reseat the ROM in its socket — corroded socket contacts are a very common cause of this exact symptom. If reseating doesn't work, the ROM itself may need replacement. You can get replacement System 11 sound ROMs from Marco Specialties or check Pinball Life for the specific Whirlwind speech ROM set.
If the ROMs test good (burn a fresh set from known-good EPROM images as a test), the CVSD decoder chip may have failed. Also check the small electrolytic capacitors in the speech amplifier section of the sound board — a dried-out coupling capacitor can block the speech audio signal entirely while leaving the music path unaffected. A full cap replacement on the sound board is good preventive maintenance at this age and can resolve subtle audio issues.
yemons·3/21/2026