Restoring a Criterion RV-6
Posted By Ron Oehlert
You remove the drive housing cover and then loosen the three spring-loaded clutch plate pressure screws until RA axis rotates freely. Then adjust balance weight(s). Once balanced, re-tighten the pressure adjust screws such that tube may be hand-slewed but drive tracks correctly (too loose can allow drive slippage in use with mis-tracking a result). Once clutch friction is set to your satisfaction under the stars (trial over several nights; temperature can affect final preference), replace cover. BTW, I have a 6" f/9.3 Criterion Deluxe Observatory Dynascope and an 8" f/7 Criterion RV-8. Also, the same technique applies to vintage Meade, Cave, Parks, etc drives with enclosed clutches.