I did it with mine. You don't get silly sounds in attract mode UNLESS you are pressing the flipper buttons. Then you can hear each of them individually. The delay should not be but a second or two after full boot. Make sure all those roms are in the right positions. Roms need to be CAREFULLY removed/installed. Final thought is roms were not burnt correctly.

In addition, there is no adjustment for silly sounds. Only an adjustment for attract sounds on or off. Once you install those special roms, what is on them is what you are going to get.

All the characters recorded their own speech for instance Picard says "we will never surrender--unless you pay us enough" and the doctor says things like "do you realize most of my patients die" and "do you have medical insurance?" etc. Roms can be burned from IPDB.