齒輪模數 gear modules estimation of 144 tooth gear in eq1/2 series mount: using evolvent spur generator generated image: actual photo of the RA gear: Always check the worm gear is meshing properly , and aligned with the RA gear, this angle can be slightly adjusted by the two screws sideways: this direction below can be adjusted: However, this tooth to tooth gap distance below cannot be adjusted (this is major handicap of this series of eq mounts), allowable tolerance of H7 to H8 means 20 to 30 microns: In case the RA gear is worn, backlash will increase, and periodic error will be larger. Wild guess of damage: 1 worm is screwed in/out too much that it's actually grinding the RA gear. 2 The counterweight is missing or highly un-balanced, and actually metal to metal grinding by the worm gear. 3 poor gear material is the least suspect, as there are so many such mounts in the market, and this is not so common Another case, DEC gear clutch not locked prop...