Does anyone here have a hardware / firmware version of Sega's Twister in which they can disable the digital knocker?

My Starship Troopers for example has it in the setting menu to disable the knocker entirely but leave volume intact.

Twister when you reach the awards blares out a ultra high pitch siren yelp and causes my autistic son to have fits. He has no problem playing with the music and normal audio but when the knocker goes off it sets him into a panic.

I'm trying to find out if any ROM version has that ability as my version can't turn it off in the diag settings.

Thoughts?

Anyone modify code or ROMs to add a feature like this? Wish it was a physical coil knocker would just disconnect it.