Problem with AM5N

wc60Ld8X

Same here, got mine AM5n in december 2024 and it worked fine till last week.
Tried different settings on different nights and even Agr 100%, nothing helped.
Its is a SQA55 with ASI2600 Air.

I've also made a short screenrecording of the ASIAir App, the mount does not move as fast in one direction as in the others.
Video

CS, Adam

fotisr

wc60Ld8X hello Adam
I'm having exactly the same issue with you for 2 days now. Happened after the latest firmware update. Did you have any resolution, any lead of what might be the cause? Thank you in advance, Fotis

F5146666

ASIMount-ZWO Can somebody from ZWO please take care of this issue.

There are many people having troubles with sudden RA tracking offsets caused by this mount.

My assumption is here that the sideral tracking rate does not fit to every Mount/Setup and seems to change/drift over time. My issue with the RA motor suddenly snapping back when tracking is activated with my Telescope being on the east side of the pier can currently only be mitigated, when counterweight is being increased way over the 5kg limit.

ASIMount-ZWO

F5146666
I'm sorry for the negative experience you had. Please check data 20cm and 25cm. The bigger the data is,the lower the load capacity is.

F5146666

ASIMount-ZWO

Interesting. You are advertising the AM5N with the following information:

Let's calculate the torque for the specified C11 setup that is shown in this picture in detail (downloaded from the ZWO homepage today):

C11 Tube: 11.28kg
Finderscope: 0.50kg
ASIAIR+: 0.22kg
ASI585MC: 0.13kg
Cables: 0.15kg

Considering the total weight of 12.28kg and a lever arm of about 28cm (from the RA-axis to the center of gravity of the C11) the calculated torque without using a counter weight is:
12.28 * 9.81 * 0.28 = 33.73Nm (this exceeds the stated maximum output torque by 12%)

Nonetheless, I already found the root cause of my RA spikes/issues. I disassembled my mount even further and found out that the breakaway torque of the RA harmonic drive is higher compared to the DEC harmonic drive. The DEC harmonic drive also runs smoother and is clearly easier to move. For me this was only recognizable when removing both motors and belts.
So I decided to interchange both harmonic drives and afterwards my RA issues were immediately gone. Now I partially have issues in DEC (what I was expecting somehow).

Please respond how to proceed. I need a replacement harmonic drive for the DEC-axis and as you can read - I am capable to change it myself. You can also respond to my support inquiry/ticket (that is still unanswered).

BR Andreas

ASIMount-ZWO

F5146666 I have forwarded your experience to the R&D team, and they are working hard to analyze the issue. I will let you know the results as soon as possible. Also, the ticket issue you mentioned is not handled by my department. I apologize for the lack of a timely response.

ASIMount-ZWO

F5146666 Hello! Please submit your device for after-sales repair for system diagnostics. What is the ticket number you submitted? I’ll help follow up on the progress for you.

F5146666

ASIMount-ZWO

I did not receive a ticket number and did not receive a response in general after writing my support inquiry over the ZWO support form. I guess you will have to look it up via my E-mail address.

F5146666

ASIMount-ZWO

Could you please advise how to proceed. Thank you!

fotisr

ASIMount-ZWO can you please look into this problem and advise for further action?

wc60Ld8X

fotisr hello Fotis,
I don't have a solution. It seems to be a mechanical problem in my case. Yesterday I tried PHD2 and had the same issue.
CS, Adam

fotisr

wc60Ld8X I'm sorry to hear that. That is what I'm afraid of, so I try to by pass the asiair in ASI2600MC AIR and experiment with PhD and a PC, to see if this persists. I hope you fix this soon, Fotis

F5146666

Adam, Fotis,

as my root cause of this problem is the RA harmonic drive itself, I tried something as temporary workaround that you also could try. Give your RA axis a couple of turns in both directions in maximum speed without your scope/imaging setup attached to the saddle (I know...this will take a while). This improved my guiding at least for a couple of hours.

Andreas

fotisr

F5146666 that is interesting. I will try this today. If this presents some changes, even for a few hours, it will mean that it's definitely a hardware issue. Thank you Andreas!

fotisr

F5146666 Andreas, I must say, you are a genius! I rotated the the whole RA 1.5 times and then send it home so that I ended up with the RA rotated a full 360 from where it was from factory. After setting up the mount, PA and calibration I had an actually stable tracking and guiding, like it was 10 days ago, before the AA firmware update. Now, I'm not naive, so I understand that the problem is still there and it looks like it is the RA drive that becomes unstable and erratic. There is probably a fragile component that deteriorated even with very light use. My AM5N is brand new, just at its 10th night out when I got the problem and had to throw out every frame of the session. The thing is, how can I get a replacement RA drive........ Thank you for the help, have a great night!

F5146666

Fotis,

Glad to hear that this workaround also worked for you!

I think this could be something harmonic drive specific, but I honestly do not have that much experience with those type of drives. My assumption here simply was that when my RA drive becomes more sluggish over time that this might change when I change its position and/or move it for a few turns to distribute lubrication.
Probably this is a typical charactaristic of the harmonic drive itself (design issue for this specific type of application -> very slow movements for astrophotography) or a quality issue. Whatever is true, ZWO may not be aware of this at the present time.

Andreas

fotisr

F5146666 I informed the support at my bug report, I hope they take that seriously. But even if they do, it's going to be probably months before we see progress. Meanwhile, I wonder how many times this work around would be applicable. I could not test for more than 45 min as I got clouds and now rain. I hope it remains stable. Thank you again!

JrayDJZJ

I am having the same issues. I have been working with ZWO support for weeks. They have continuously pushed back that it is user error. My error only happens on the East side of the meridian.

I have just now gotten them to agree for repairs. Who knows how long it will take!

fotisr

JrayDJZJ I'm having the problem everywhere in the sky and it starts within 2 minutes of guiding on the first target of the night. I told them, that I used to have an Astro Physics 1200GTO with a 10"RC and an SBIG STL6303 15 years ago, I know what I'm seeing and I can understand the problem. Let's see how that goes... But I did a 45 min run yesterday, before clouds and rain came in that was good, that ended with great fwhm test shots. That's after I rotated the RA head 360 with the hand controller.

JrayDJZJ

Maybe it’s a batch problem. I bought mine in December 2024 and it worked perfectly for about 3 months. Now, I can guide “perfectly” for about an hour to hour and a half. If it’s east of the meridian, I start getting RA spikes. Once it does the meridian flip, I go back to guiding “perfectly” the rest of the night. I have brought my issue up on other forums and very few have had the same problem. I hope ZWO can correct the problem. They have treated me like I am an idiot. The whole time they have blamed it on user error.

fotisr

Even if doing one whole turn in the RA housing and setting up again the mount tracks and guides as it should, this falls apart within less than an hour and deteriorates fast to big RA jumps. Tonight I managed to get 3 x 300sec exposures before the first RA jump of more than 10 arc sec. This looks a lot like a fault in the RA harmonic gear and requires service.