AM5 guiding issue, random RA instabilities: Page 3

AM5 guiding issue, random RA instabilities

KHj89YaN

That's probably a long shot. The issue is apparently still a very small problem (according to ZWO USA), but I suspect that's due to a lack of reporting and opening of RMA tickets. Users are posting more on here or on other sites which is fine, but RMAs should also be opened so there is a continued flow of cases.

Support@Seestar

KHj89YaN
You’ve provided a new perspective that I find very valuable. Our current line of analysis is a bit different, but we’ve already made some progress. We will definitely take your idea into consideration, thank you.

kaelig

Support@Seestar

Hello,

I was electronic engineer during 20 years, I know when a product has default. I have no spikes before June 25. I have got a lot spikes since June 25. The mount is the same, the setup is the same and the place is the same too.

For me, there are two issues:

one with the mount: but for me, it is surely a little thing but I could not solve it by myself.
the another with the ZWO support in the future

In the USA, ZWO has a repair center
In Europe, we have got nothing !!!
We send messages on this forum like bottles in the sea.

Hence, when we have got an issue, we are not able to find a local support.

With old Equatorial mounts (not Harmonic), I could find several european companies in order to check & to repair mounts. But for the harmonic mount, there is no solutions.

ZWO makes innovatives product with good designs, that's true
and your products are more expensive than most of your challengers, that's true
If the products are better, we are OK

But for your older products, we need technical repairing solutions and repairing centers.
I am ready to pay in order to check & repair my mounts, like a car. My leasure is astronomy,
no mechanical testing.

For the moment, I have sent my mount to Optique Unterlinden in Colmar for investigations.

KHj89YaN

Support@Seestar

Indeed, I'm sure your analysis will be different since you have more tools at your disposal. What is the current ZWO analysis of the fault? Is ZWO also arriving at a mechanical issue as the root cause?

I am, again, reporting back with information that other users have posted about on various other social media and astronomy forums for visibility.

kaelig

KHj89YaN

I am sure that we need other tools that PHD log in order to investigate this type of defaults.
As customer, i only could say that my mount has not the same behavior than last year.

I have change: the tripod, the cable management, the power source, ...
I made a lot of tests with Asiair or with NINA (under Windows).

and
Finally I don't know more.

I expect that Optic Unterlinden in Colmar could find the source of my problem and solve it.

@support@Seestar Could you transmit the solutions of the USA repairing center to Optic Unterlinden
in France. thank you if you could make that.

Support@Seestar

KHj89YaN
This is possible, but to be precise, we have not yet located the ultimate root cause of the problem. We are currently analyzing whether it is a problem with the motor and harmonics, and more testing and analysis are still in progress.

Support@Seestar

kaelig The distributor will contact us once they receive your unit, and we will provide them with the necessary assistance.

kaelig

Support@Seestar

Many thanks for the assistance to Optique Unterlinden center for my issues.

Send the mounts in China is not the best solution for everyone.
A local assistance in Europe will be a better solution for you and for us.
Of course in case of big issues, ZWO assistance in China could become necessary.

祝您旅途愉快
Zhù nín lǚtú yúkuài

retman

Support@Seestar This is an excellent response. Thank you!

KHj89YaN

Support@Seestar

Thank you for the detailed response and information. It's much appreciated since I'm trying to keep track of this issue. Is ZWO concerned that this potential problem with motor and harmonics is more widely distributed amongst all AM5N units?

Support@Seestar

kaelig Thank you for your feedback. We understand that local assistance in Europe would be more convenient for users, and we will take this into consideration.

Support@Seestar

KHj89YaN Yes, this is not an isolated case, and we are actively working on a solution.

kaelig

Support@Seestar
Thank you for your reply. Optique Unterlinden seems OK to make the repair if you give the technical informations and the parts to make the job. Perhaps you could collaborate together in order to have a repairing center in Europe.

I was the first in my astronomy club to buy a ZWO mount. Thanks to my result with this mount, several friends has bought one too. I feel responsible towards them. When I write here for a lasting solution in Europe, I do not think about me but I think to them.

it will be a great improvement for the customer service.
It will make the difference with the other companies which sell uname mounts.

KHj89YaN thank you for your participation
@retman thank you for your participation

KHj89YaN

Support@Seestar

Understood.

To refine my question, is ZWO's position that this is a widespread defect/problem that will affect all AM5N mounts that have been sold to the public? Is there a potential for a recall of the product?

Support@Seestar

KHj89YaN
It is unlikely that all AM5N mounts are affected. If the issue is related to software, there is no need for a recall. If it is a hardware problem, it would likely only affect some production batches. We are actively working on a solution for the issue.

KHj89YaN

Support@Seestar

Thank you for this information. Is ZWO under the impression that there is a software issue in tandem with a hardware problem regarding this fault? Is there any timeline currently from ZWO regarding when they will be able to make an announcement regarding AM5Ns and affected models? How widespread is this fault?

Thank you very much for answering all the questions as best as you can. I appreciate it and those who are tracking this problem do as well.

F5146666

o82KUdLn

Good to read that this workaround seems to have worked also for you! (even if just temporary) Please keep us posted how this develops over time on your side.

I also did not have any RA-issues for now since I swapped back my RA harmonic drive (<0.9" total RMS). But I had the advantage that I could spin my drive with a power drill when I had it removed from the mount before installing it back again. As I only collected about 10 hours of guiding since then, I will continue testing and keep sending the PHD2-Logs directly to ZWO for review. Let's see, if the RA-spikes are coming back.

Andreas

kaelig

F5146666

Thank you Andreas for your answer. I do not understand what you have done with the power drill.
I will interested to understand it. If you have a post, I will be interested by the link.
You go further than me in the solutions 😃

F5146666

kaelig

I used a power drill to turn the inner shaft of the RA harmonic drive while holding the outer harmonic drive housing. This way I could run in the harmonic drive more quickly than using it in the mount and turning it over the RA-motor. I didn't make a video or take any photos of this process, sorry!

Hopefully this explained it more clearly.

Andreas

kaelig

F5146666
thank you for your answer. I am not able to do that. Could you explain me why you do that and how it solves the issues.
It is for a better understanding.

F5146666

kaelig

Sure. When I recognized that my RA-motor is snapping back during tracking (I had to let my mount run open, without the cover & side plate to see that), I decided to start my own investigation. I am an aerospace engineer with electronics background and have experience in fault investigations down to the lowest level. When I had everything disassembled I could feel a different breakaway torque and smoothness between the DEC and RA harmonic drive, as soon as the drive belts were removed. This was when I suspected the RA harmonic drive to be the root cause of this issue (and I still do). At this time I was not aware that there might be a wave spring washer inside the drive potentially causing breakaway torque (thanks to the member of CN that gave us this valuable insight). Very small and slow movements are horrible from lubrication perspective. So I thought giving the RA harmonic drive some turns could distribute the lubrication more evenly and probably also move/break up potential debris. But the wave spring washer (if installed at all) would perfectly fit to this failure pattern.
But let's wait and see what ZWO's investigation ultimately concludes. I offered them my help for this investigation and still are.

Andreas

KHj89YaN

F5146666

Indeed, I am also thinking that the wave spring washer is probably the root cause. Depending on where it was procured from, perhaps a different vendor than the original AM5s, that could account for it potentially being machined at a different quality.

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