Rowan Belt Mod HEQ5 - Weird Noises?

[Danield06]

Hi everyone,

I go the rowan belt mod in yesterday and installed it. I have not had the chance to test it out because of cloudy skies. However, I noticed that the DEC drive sounds different from the RA drive. I am also hearing a weird slight purr/grind noise when using the DEC drive. It almost sounds like it's dragging on something and it goes in and out. It actually sounds like a worm gear thats making the noise, the tighter I make the belt the worse the noise gets. 

Does anyone have any tips? I do not recall hearing this when I used to have the gears. 

[Stu Wilson]

I've just fitted mine a couple of weeks ago and had to take apart and back together. Sounds like a similar problem.

Think back to when you put the new gear drive on each motor. Did you put them on so the gear sits flush with the end of the shaft? I hadn't and got that awful grind noise as it WAS grinding.

I loosened the Allen bolts and tapped the gear flush.

Back together all great.

Also if you preload the bearings too much youll get horrible noises too.

I hope this helps.

 

Stu

[spillage]

Possible worm gear binding too tight/loose?

[sloz1664]

After completing a successful job of completing the Rowan mod, all you should hear is the whine of the servo motors and any additional noises are a fault somewhere. Undo the clutches and see if the RA & Dec axis are free and moving smoothly. If not, look at this strip down & rebuild from Astrobaby. If your Ra & Dec are OK, remove the motor board and have a look to see that the belts are aligned & the timing pulley are not rubbing on the housing. I had to remove a rough segment of my housing  to allow the timing pulley to rotate freely.

Steve

[Danield06]

8 hours ago, sloz1664 said:

After completing a successful job of completing the Rowan mod, all you should hear is the whine of the servo motors and any additional noises are a fault somewhere. Undo the clutches and see if the RA & Dec axis are free and moving smoothly. If not, look at this strip down & rebuild from Astrobaby. If your Ra & Dec are OK, remove the motor board and have a look to see that the belts are aligned & the timing pulley are not rubbing on the housing. I had to remove a rough segment of my housing  to allow the timing pulley to rotate freely.

Steve

Thanks!

 

It is a very quiet noise I am hearing. Like a hum that goes in and out. I may be over thinking it as I really have to listen closely when I am slewing. However, I do know that the more I tighten the belt, the more pronounced the noise is. I can make it very noticeable or I can make it very very quiet based on belt tensioning. I went back and changed the tension ever so slightly. We will see how it is next time out. Ill also look at astrobabys guide, I am thinking it is a worm gear adjustment, I can hear it best when my ear is next to the worm gear. I know that pretty much all of my gears are aligned. However, what do you mean removing a rough segment of your housing? The motor housing or the motor board cover? 

Thanks for the reply!

 

[Danield06]

9 hours ago, spillage said:

Possible worm gear binding too tight/loose?

I am thinking that this is a possibility! Ill have to do some adjusting. The whole reason I had done the belt mod is because my RA tracking was bad. I was getting very noticable elongation, and I have already noticed a considerable improvement with the belt mod. However, I believe I can dial it in more, hopefully removing this noise in the process

[Danield06]

On 14/08/2020 at 10:48, Stu Wilson said:

I've just fitted mine a couple of weeks ago and had to take apart and back together. Sounds like a similar problem.

Think back to when you put the new gear drive on each motor. Did you put them on so the gear sits flush with the end of the shaft? I hadn't and got that awful grind noise as it WAS grinding.

I loosened the Allen bolts and tapped the gear flush.

Back together all great.

Also if you preload the bearings too much youll get horrible noises too.

I hope this helps.

 

Stu

Hi Stu,

Are you referring to the small gear that we had removed form the shaft or the big worm gear? I believe the small gear that we removed is sitting flsuh, but I will have to check that out. Maybe its causing some weird issue that is affecting the worm gear. I may also be preloading the bearings too much. I have played around with it so that the noise is super quiet and unnoticeable unless you really get close and listen for it. I can continue to make adjustments after I go out next time. 

 

[TerryMcK]

If you can get a decent audio recording of what you are hearing and post it then that will be good

[SiriusB]

Unfamiliar with the application, but short(in particular) poly timing belts t5,t10 series or whatever really don't need a lot of tension to work correctly.

Too much tension will be a strain on the (small?) motor/worm bearings .

Aim for minimum tension without slipage would be my advice.

[Danield06]

5 hours ago, TerryMcK said:

If you can get a decent audio recording of what you are hearing and post it then that will be good

Honestly, it is masked by the slewing noise of the motors. Couldn't hear it on video. 

[1parsec]

Does the 'humm' noise change when you change the slewing speeds on the hand controller ?
If the noise is that quiet it's likely it's not to be a problem.

How tight are the belts?  Too tight is bad!   You should have 1-2 mm deflection of the belt with light finger pressure.   @SiriusB comment is spot on.

To evaluate tracking performance you need to record a guide log with the actual guide corrections turned off.  
i.e the camera is then recording the change in position of the guide star caused by the tracking errors of the mount - the PE.

Then load that file in to EQ mod's  PecPrec or PHD2 viewer.  The graphs will tell you exactly what the errors are and where they're coming from.

 

[Danield06]

On 16/08/2020 at 04:42, 1parsec said:

Does the 'humm' noise change when you change the slewing speeds on the hand controller ?
If the noise is that quiet it's likely it's not to be a problem.

How tight are the belts?  Too tight is bad!   You should have 1-2 mm deflection of the belt with light finger pressure.   @SiriusB comment is spot on.

To evaluate tracking performance you need to record a guide log with the actual guide corrections turned off.  
i.e the camera is then recording the change in position of the guide star caused by the tracking errors of the mount - the PE.

Then load that file in to EQ mod's  PecPrec or PHD2 viewer.  The graphs will tell you exactly what the errors are and where they're coming from.

 

Thanks! Next time I am out I will try and see what I can do. I use ekos and I have never guided without corrections. I will see what I can do with it