Celestron CGEM II Complete Hypertune Tutorial

[@xee1429]

Thank you, been looking for a video like this for a very long time.

[@BS-oi7ts]

I have a CGEM-DX. Bought it new in 2014, haven't tried to use it until now. It was bad out of the box. Spur gears not meshed properly, brass cups on the worm wheels dragging on the housing, dec and ra, motors not adjusted correctly, centerline of worm gear/wheel way off on RA, altitude axis sticking, azimurth axis movement binding, threaded holes completely messed up from factory and the list keeps going. There's a reason that you don't see many celestron mounts on youtube astronomy sites. I used your video as a guide, did a couple things a bit different, but achieved the same results that you did. Thanks a bunch, well done.

[@Sweatsox8]

Yah the quality control bar is set pretty low with some of these mounts, its pretty sad for the amount of money they cost and you can't use it out of the box. I'm happy my video was helpful to you. Thanks for the comment.

[@stevendrexler6138]

Great video, I have been looking for someone to post a detailed video like this! I am getting good guiding right now despite sticktion in the RA, so I will wait until it's a problem before doing this as I can now see it is a very involved process.

[@Sweatsox8]

Thanks Steven, yes it can definitely be quite the project. I agree if it isn't broke don't fix it. In one of my previous hypertune vids from 3 years ago I explain a possible quick easy solution to stiction that doesn't require you tearing the mount apart. Its a simple process of slightly slacking off the locking nut in either your RA or DEC. You can check it out. By doing this procedure it won't effect your mounts performance since your getting good guiding, but can alleviate bearings from being bound up making balancing easier. kzbin.info/www/bejne/hpyyXnukhbmEask

[@milordinz]

Thanks I am using this video as a reference it has been a great help

[@Sweatsox8]

That’s great. I’m glad you found this helpful.

[@10intexas]

If the bearings are intact and undamaged would removing the old grease and and repacking with the synthetic lubricant accomplish 80-90% of what would happen with new hybrid bearings?

[@Sweatsox8]

Yes I believe it would for the large and small bearings. It’s a good idea to inspect the internals anyways. If the grease in yours looks like mine it’s gunky and thick. Changing it will make a difference. But I will say the ceramic hybrid bearings are superior in my opinion but you’ll be fine either route you decide.

[@10intexas]

@@Sweatsox8 Have you ever disassembled the gear boxes on the RA and or Dec motors. Is there any maintenance like changing to the synthetic grease to be done in there? Also, could you add a link to download the worksheet. I would like to use it to do my tune up.

[@Sweatsox8]

@@10intexas honestly I can’t remember if I opened up my motors at all. I know my one motor was making really awful noises after my incident. I knew it was pointless for me to try and troubleshoot it since there was no way to buy parts if I found broken gears so I just bought new motors and saved the old ones for future repairs if ever necessary. Sure u can open them and relube but lots of small parts and if it’s not broken don’t fix it. You may cause yourself a headache unwittingly. I wouldn’t recommend taking the motors out or apart if u don’t have to. It’s another set of gear meshing you’ll have to fuss with upon reassembly later. I couldn’t seem to find a way to share the worksheet PDF I made in the video description. If there’s a way I can’t figure it out. So instead in the video @ 1:03:05 there is a blank copy. I figured folks can screenshot and crop to print their own. I hope that’s suffice. Have you begun a tear down yet or are you in preparation stages?

[@AMUSAINC]

Just researching at this point. I suspect I may have bigger issues than just "stickidge". One of the saddle tightening bolts was slightly bent when I got the mount used. I did not think seriously about it but I just noticed as I was tightening the counterweight shaft to attach the weight to see how good or bad the R/A free swing is the shaft was slightly bent. I suspect the mount toppled over at some point. Though there is no sign of damage the dec is hard to move but the RA swings 7 times before stopping. Gonna adjust the clutch and I hope doing a "tune" with new bearings fixes the problem. I believe I am going to go your route and order the parts from AZ and a sheet of PTFE to cut out the shims. You did a great job so I doubt the video from DSP that comes with their DIY kit would be any more complete or informative than yours.

[@Sweatsox8]

@@AMUSAINC ouch, I hope there’s no serious damage. Before my first tune up my RA swung about the same and when it came to a stop it was a sudden stop. Dec wouldn’t move, only by hand. It was super tight. I couldn’t find spacers anywhere online for some reason, only the sheets. The most dreadful part of this entire project is dialing in the gear meshing. Last time I must have got lucky first night out I had to make a small tweak and boom I was off to the races. This time around. It took me 3 nights to get it good where I’m guiding consistently between a .45-.65 most of the time. Not to mention I took the mount back apart a few times. First I had both axis shaft lock nuts too loose, with the slop couldn’t mesh gears properly, then I tightened lock nuts too tight, finally found the Goldielocks zone. Very frustrating! I filmed my ordeal but haven’t had the time/energy to make it to a video to post. Hope ur have good luck with yours.

[@BS-oi7ts]

good detailed video. I can't seem to find the teflon spacers, where did you get your set?

[@Sweatsox8]

I bought mine almost 4 years ago and can’t seem to find them anymore. You have a couple options. 1st either use the already installed shims and forgo this step of the video. 2nd I believe Deep Space products sells them but may only be included in hypertune kit. You can reach out to them and inquire. Or 3rd option would be to buy it in sheet form and cut them yourself. I would recommend the .010 thickness if u were to buy one size and u can stack. Here’s a link. Hope this helps. www.eplastics.com/PTFENAT0-010X12