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DDM 60 intermittent tracking failure


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#1 whwiii

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Posted 19 February 2019 - 07:18 PM

hello
my 2011 DDM 60 is not tracking well:
it will point and track well initially
but then intermittently slews away from the target in RA (with software showing change in position)
sometimes it will come back to the original location after a minute or so, other times it will give an error ?voltage? and stop tracking.  

the mount is well balanced and has tracked smoothly for years
(heavily used)

i've no idea where to start on trouble shooting.
i've never changed the bearings
new power source, cables?

any help would be appreciated.  

thanks

-bill warden

 

http://astrowhw.blogspot.com/

 


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astrowhw.blogspot.com


#2 MarkS

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Posted 19 February 2019 - 10:38 PM

Very difficult to advise based on your post.

I think the first thing is to examine the Clservo logs. If you are not logging this data you need to go to Control>Misc settings>Enable log file.

Examination of these files during and after a run will tell you what the tracking errors and motor currents are in very fine detail.

This information may help pinpoint the trouble.

 

Mark


Edited by MarkS, 19 February 2019 - 10:39 PM.


#3 Waldemar

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Posted 20 February 2019 - 07:33 AM

"intermittently slews away from the target in RA (with software showing change in position)"

Does this mean your mount goes faster, or does it stall?

If it stalls, and your log shows a rise in current, that could indicate a rough running bearing ...

Did you make any changes in your set-up lately, which might cause a radial imbalance? 

 

Like Mark already mentioned: your logfiles may shed some light on this.

 

 

Reading the logfiles is an art on its own, but I am sure ASA is willing to help you in any way they can.


Waldemar
--------------
Mount: DDM85 Standard 12V ; Telescopes: TEC140 + 140FF + Quad TCC ; Celestron RASA; TMB 92SS + 27TVPH Cameras: ZWO ASI 174MM cool; SBIG STF8300M; ATIK4120EX; TRIUS SX-36
Filters: Astronomik and Baader NB + RGB; Lunt double stack 75 mm unobstructed signature series + BF 3400; Dutch weather and light polluted skies.  

#4 GeorgeCarey

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Posted 20 February 2019 - 08:35 AM

I had huge problems with this sort of error and my mount went back to Austria several times. In 2015 it was finally sorted out. Nobody ever found a definitive reason for the problem, but it was most likely the bearings.
I monitored the motor currents and wrote a spreadsheet that displayed the currents on a graph. It could clearly be seen that the mount would track ok but the current in the
RA axis would slowly rise. When it hit 5A the mount would throw an error message and then do a slew to try and fix the error.
I will find the spreadsheet and send a copy.
When the mount last went back to ASA I asked them to run it for at least 8 hours and send me the log file.
The currents stayed steady well below 1 Amp so I was happy to ask for the mount to be sent back.

ASA DDM60Pro, homemade 8" and 10" reflectors, QSI 683 camera, Astrodon 5nm filters, Pulsar dome observatory. Website: http://www.geoastro.co.uk


#5 GeorgeCarey

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Posted 20 February 2019 - 08:42 AM

Have a look at this thread.

http://forum.astrosy...rising current

ASA DDM60Pro, homemade 8" and 10" reflectors, QSI 683 camera, Astrodon 5nm filters, Pulsar dome observatory. Website: http://www.geoastro.co.uk


#6 GeorgeCarey

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Posted 20 February 2019 - 09:33 AM

This is the spreadsheet.

http://geoastro.co.u...nalysis_V20.xls

 

All you need do is:

 

Get the logfile

Select everything (CTRL-A)

Copy   (CTRL-C)

Click on the button 'Process'.

 

A graph should be displayed.

 

I haven't used the spreadsheet for years so there may be bugs. It was written with Excel 2003.


ASA DDM60Pro, homemade 8" and 10" reflectors, QSI 683 camera, Astrodon 5nm filters, Pulsar dome observatory. Website: http://www.geoastro.co.uk


#7 whwiii

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Posted 21 February 2019 - 04:22 AM

thank you all for your considered replies, will capture log files when the rain clears


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astrowhw.blogspot.com


#8 MarkS

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Posted 21 February 2019 - 07:19 AM

Bill,

 

You don't need clear skies. Just run the mount on a target in The SkyX - for up to several hours if necessary. No need for camera etc....

 

Mark



#9 Artem

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Posted 21 May 2019 - 12:03 PM

Hello Mark, do you mean with "You don't need clear skies. Just run the mount on a target in The SkyX - for up to several hours if necessary. No need for camera etc..."

 

To connect mount " autoslew " to TSX and then chose a target in TSX and that should be enough ??

 

You do not need / mean to AUTOGUIDE right..

 

Regards

 

Martin


Edited by Artem, 21 May 2019 - 12:03 PM.


#10 whwiii

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Posted 21 May 2019 - 06:34 PM

Hello Mark, do you mean with "You don't need clear skies. Just run the mount on a target in The SkyX - for up to several hours if necessary. No need for camera etc..."

 

To connect mount " autoslew " to TSX and then chose a target in TSX and that should be enough ??

 

You do not need / mean to AUTOGUIDE right..

 

Regards

 

Martin

right, no need to autoguide, don't really even need to choose a target.  just let it track a random point in the sky

 

follow up on mine

i did run a log and sent it to ASA

they were kind enough to review it

and inform my that it was definitely a bearing problem, the only way to solve it would be to send the mount in for service, which is tough from the US. 

 

FWIW, might be my imagination, but i found that if i warm it up by moving the mount manually back and forth rapidly, and making sure the weight is perfectly balanced for the intended target, tracking is a bit better. 

 

i seem to recall a ring with bearings for my ASA DDM 60, is there no way to change that?

 

thanks

 

bill w

 

PS here's my log

https://www.dropbox....20h18m.txt?dl=0


Edited by whwiii, 21 May 2019 - 06:35 PM.

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#11 Artem

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Posted 21 May 2019 - 06:40 PM

THank you Bill,

 

Regards

 

Martin






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