Agreed, get the manual. My dad has a rock ola grand prix that will eventually make its way to my house. The mechs do get gummed up from the old grease. The best thing to do is take it apart, degrease, oil and reassemble. If things are really seized you can use a heat gun (carefully) or a hair dryer to soften the grease. I've heard that some people have had luck using a hair dryer and flooding it with new oil.
Once I got the mech running I had a problem where the speed was too slow. It turned out to be the rubber grommets that hold the turntable up. They dried out and we're causing the turntable to spin at 33 rpm instead of 45rpm.
The amp may need to be re capped as well.
I still have some issues with it but since it's not at my place haven't spent much time working on it.