Keth,
Do you have any FFT graphs you could share?
If you have a large 9.6s error then the pinion gear bore hole is likely off center. The 80s error is very interesting, and possible confirmation it comes from this design of the gearbox. I have this issue with both the 80:1 and 125:1 gearboxes I use. I've previously mentioned not really liking the 25:1 gearbox. It seemed to have a lot of play in the output gear. For the Dec axis why not stay with?the stock gearbox. The issue here is backlash. The frequency response is really not important. I've started a separate thread discussion on the backlash issue. ?The good news about the 80s error it can be removed with a PEC curve. But have you read the thread on increasing the number of steps either via the gearbox ratio or the encoder for much improved RA performance? I have virtually no high frequency noise. The 125:1 gearbox uses the same pinion gear the 25:1 gearbox. My Ra is guiding at around 0.6 arc-sec rms with not sudden jumps. I just have that 80s error. I also changed the coupler to a one piece rigid one. I just posted how one can do this for under $10. You can find details here?
/g/Losmandy_users/message/72710Peter
