HEQ5 Pro Tracking Problem

[Mikey0368]

I'm wondering if anyone can help me get to the bottom of a problem I'm having with my HEQ5 Pro with Rowan Belt modification. It will track for about 20 minutes and then something goes wrong that stops it tracking on one axis. The attached pictures are both from last night, one before the problem kicked in and one after. I also have a couple of YouTube videos that show the noise that it's making........

https://www.youtube.com/watch?v=YTlcFN95SEM

https://www.youtube.com/watch?v=ncJEcX5cPzQ

The noise began when I got a new StellaLyra 8" Classical Cassegrain a couple of months ago and although it's within the payload limit of the mount (9.1kg) it seemed to struggle with it right away. Have any of you seen this problem before?

Needless to say it's a couple of months out of warranty!

 

Edited January 9, 2021 by Mikey0368

[Dr_Ju_ju]

Sounds like something isn't meshing properly, or there could be some dirt on the drive worm inside the mount, so if your feel competent enough,  I'd start by stripping down & cleaning everything...

Also try running the motor with the belt removed, just to check that the motor is ok... 

[Mikey0368]

Thanks. I also posted this in the Skywatcher Mount facebook group and got a similar answer.......

Quote

Had this kind of problem when I bought my second hand heq5p. Of course it was not all the time, after breaking my head a while I discovered that removing the belt and turning the worm gear It was like « missing the tracks » in one direction but really, like it was slightly touching the axis but not good enough. Had to tweak the « worm gear engagement » while checking everytime turning the worm by hand to find a good position where it operate good in both direction.

It was empiric but not hard.

Since I have a small play that I didn’t fix yet but it perform way better and more than the rest, it doesn’t do this « slewing alone » thing anymore.

For mine I’d love to open, clean, régrease, and see how it looks inside to set it up like perfect but for the moment (if I was clear enough) it works pretty nice.

Oh, and I was checking the RA / Dec axis with all setup on it.

To remove the belt you first have to loose the motors position, there are many tutorials online, also a website from « astrobaby » which will explain this even better than I.

Hope it will help

 

[malc-c]

Looking at the first video the sound matches one revolution of the worm drive.  Either the worm need re-meshing or the end float bearing is loose.

One further possibility is balance and CG since you fitted the new OTA.  It looks a tad top heavy so the CG may be out.  It's an old video, but the concept of balancing and setting the C0G correctly is covered in Dions video

https://youtu.be/hGduG2jB9ec

[1parsec]

Hi, 
It looks like the noise is in sync with each complete revolution of the belt.  This could point to the belt tension being too tight. 
Loosen the tension a fraction and see if that help.
 

 

[newbie alert]

Sounds like just the RA,  has  the pinion got a slight osolation and maybe the belt rubbing on the casing? I'd you slowed the speed down on the handset then you could see at which point the rub sound is..