Topcon SL-D Series Slit Lamp Grinding or Stiff Joystick Elevation Control: Gear Holder Replacement

Most of the time stiffness is due to old grease slowing down the spindle shaft as it threads through the gear holder. Sometimes due to dropping of lack of grease the threads on the gear holder get stripped or cross-threaded. If you see brass shavings on the joystick pad or hear grinding when turning the joystick, that is an indication the gear holder threads are breaking down.
By taking the gear off first, you can isolate the problem area to either the joystick assy or the spindle assy.
If it is just stiffness, the spindle shaft and gear holder threads need to be completely cleaned and re-greased. The middle section of this video discusses that issue starting around 15:29 minute mark.
**Upon reassembly if you decide to take the 3 hex screws off the top carrier to position the upper spring washers, be aware that this will release your main spring, which is what you would do if replacing the main spring. Around 30 minute mark.
Part Diagrams at end of Video.
Gear Holder part #20 4492102030
Main Spring D2/D4 # 33a 4492103010
Main Spring D4Z # 33b 4492105010
Side Note: I used 2 different bases in this video. The one that was making noise when operating the joystick is an old one. It needed to be cleaned and greased. 😆