If its 22 year old analog converted to digital, there is very little you can do. Forget about taking out grain, it can’t be done. You can try fiddling with the color curves, color corrector, primary and secondary correctors.
Your best bet is to get a broadcast monitor—-You can run it using firewire through a camera that supports passthru, or better yet, your tape deck. Of course, you should calibrate your broadcast monitor.