I just picked up my grail pin Lord of the Rings. One of the issues it had was no sound.
I checked stern's web site and came across service bulletin # 157.
AT this time Stern's web site has a broken link for the new OS. I had them email me a copy. ( so if it is still not fixed, pm me and I can email you a copy)
I burned a eprom with the new OS. Followed instructions to update. I then reinstalled the original sound eprom. No sound. I erased eprom and burned a fresh copy of the sound rom file. I reinstalled the sound rom . Boom I have rocking LOTR sound.
Just providing some info for the data base. When I searched on pinside, I saw no posts covering this.