Hi friend of my Uncle Bob!
The video walkthrough at that link that Rush's supplies above is quite helpful -- it's a good find!
The walkthrough is in several parts -- the last one, called "Solomon's Treasure" has a disc puzzle at about 1:30 (1 minute 30 seconds) in. I THINK that's the one you're talking about.
My memory is that you mostly have to be very quick, once you've figured out the strategy.