Moin

I finally finished my latest "project". This time it's not a picture but the improvement of my guiding. I had some trouble with my guiding and overall tracking and started to investigate and eventually take action on that matter. I documented the overall process in this video (it's more of a showcase than a tutorial):

>>>>>>>> YouTube: EQ6-R Tuning <<<<<<<<




Motivation
After I switched from HEQ5 to EQ6-R pro, I noticed some periodic errors in my subframes. After some testing I narrowed down that with an exposure time of 240 seconds, every second frame shows a tracking error with the same direction and magnitude. The following gif shows some consecutive example subframes (left before the tuning and right after the tuning).

It's better visible in the YouTube video - but one can clearly see a systematic error in every second frame, before the tuning. After some research I learned that the RA worm gear has a period of 480s... since this couldn't be a coincidence I run an FFT over an old guiding log and detected a big peak at 480s:



Therefore, it was obvious that there might have been some damage on my RA worm gear
Possibly due to transportation with a locked clutch?!

Another Problem is the big backlash in my DEC axis which - According to the PHD Guiding-Assistent - lays at 72 seconds!!



The Assembly

The actual reworking (disassembly, cleaning, reassembly) took around 8 hours for a noob like me. One Allen key broke inside the housing which was a severe issue ... so use high quality tools if you want to try this at home  the only other noteworthy thing is that pulling out the bearings was a pain in the A$$... so maybe buy a bearing puller for that one. Other than that, everything went according to tutorials (listed in the actual YouTube video's description).




Summary

The final results speak for themselves
Before the tuning I had long periods of 1.20" guiding (and in average a guiding of 0.70"-0.90") and in addition those periodic tracking errors. After the tuning those errors are completely gone and my guiding is so far stable between 0.4"-0.6" (sometimes even at 0.3").

• assembly ~8 hours (change bearings and grease; for my case only: also change RA worm gear; belts were still fine)
• "mechanical" backlash tuning #1 ~2 hours (Tip: remove the caps so you can see the gears and belts; put the handcontroller to 2x speed and single tab into one direction and back; observe the gear; if the gear moves in both directions the backlash is ready for fine tuning; if the gear only moves in one direction tighten the adjustment)
• belt adjustment ~1 hour (there are two directions in which you can adjust the worm gear in order to reduce the backlash; one direction is via the final adjustment screws on the housing and another direction is via a ring-screw that fixes the overall worm shaft; both of these adjustments also affect the position of the gear that rotates the belt! This is often forgotten in tutorials, so you actually need to make sure to readjust the belt tension after bigger backlash adjustments! My belts were too loose afterwards which introduced additional backlash)
• "mechanical" backlash tuning #2 ~2 hours (install scope, cables and counterweight; test if the assembly 'wobbles' in either axis; if yes, tighten the screws; if not, try to slew the mount at the complete working range; if binding occurs, loosen the screws; if not, you are done)
• backlash fine tuning ~2 hours (check the backlash with PHD guiding assist; if backlash occurs repeat backlash tuning method #2)
• cable management ~3 hours (turned out to be super important!!! I thought I already had a good cable management but it was too asymmetric, not centered and pulling on the scope; the new cable management brought a significant improvement)
• balancing ~1 hour