I purchased my RC-33 (22-650) in 1984 and recently did a thorough cleaning, lubrication and adjustment. Below are links to all the information that I found useful.
Sharpening the 13 inch blades has been the biggest challenge. I used to get them done by a good sharpening shop, and they came back not only sharp but straight. Straight is important because you want all three blades to be cutting into the wood evenly. That sharpening shop went out of business in the 2009 recession and I could not find another local shop that would sharpen the blades straight. Straight means no light when sharp edge of blade is held against a steel ruler. I tried to sharpen blades myself with a Makita 9820-2 surface grinder. I could get them sharp but could not get the edge dead straight.
Finally decided to replace the cutter head with a Byrd Shelix helical segmented head. Glad I did: no more sharpening; no more knife setting; and much less tear-out when planing difficult wood. When the carbide cutters get dull, just rotate them 90 degrees to expose a new sharp edge. When all 4 edges have been used, then replace that cutter. Only the cutters which are chipped or dull need to be rotated, so no waste. It is a great system and cheaper than paying to have straight blades sharpened.
As there were no upgrade instructions available for the RC-33, I created a YouTube video which also shows lubrication and adjustments of the RC-33. Even if you are not changing to a helical head, the video is worth watching for the lubrication and tune up info:
YouTube
After watching the video, you may find it easier to work from written instructions, which are available in the following folder, along with other documents for the RC-33, including instruction manual and parts diagram:
Folder
RC-33 Tear down and restoration blog by Ed Hollingsworth:
Blog
Set of Triple drive Belts can be purchased here:
Belts