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ETX90-EC RA drive is noisy and slipping

Meade Maksutov
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3 replies to this topic

#1 Prasad

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Posted 13 August 2021 - 02:23 PM

I have been trying to fix an ETX90-EC. Each time I fix a problem new one appears. The latest one is from RA drive gear train. The gears appear to be OK because I do not see any broken teeth on any gear. When I press the East or West button the motor runs for a while and then suddenly the noise gets louder and drive movement stops. I see the 1st gear vibrating while spinning and apparently slipping from the next gear. The clamps are all tight and I have tried pressing them down with my fingers. No teeth are broken on any gear. This has been extremely frustrating so far.. 

 

Any suggestions? 

 

Prasad 



#2 stevenk

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Posted 14 September 2021 - 07:00 AM

Prasad Hi 

The ETX is generally noisy but a great optical grab and go.

I have one myself and I consider it the best optical performer compared to other scopes I own,  and others I have seen through.    

There is a site dedicated to the ETX with many fixes and suggestions. 

 

Here is the site which also compliments a book by the same author 

http://www.weasner.com/etx/menu.html

 

Hope you can find the answer here 

 

All my best 

 

Steve 



#3 Prasad

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Posted 14 September 2021 - 09:24 AM

Prasad Hi 

The ETX is generally noisy but a great optical grab and go.

I have one myself and I consider it the best optical performer compared to other scopes I own,  and others I have seen through.    

There is a site dedicated to the ETX with many fixes and suggestions. 

 

Here is the site which also compliments a book by the same author 

http://www.weasner.com/etx/menu.html

 

Hope you can find the answer here 

 

All my best 

 

Steve 

Thanks for the reply Steve, yes I have scanned through the entire website. My problem apparently has not been answered. There was at least one mention but that was several years ago. The guy was able to find a replacement gear drive system from a "spare" unit. I have advertised on CN classifieds for a broken ETX or it's gear system but so far no reply. 

 

CS
Prasad



#4 kg74

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Posted 15 September 2021 - 03:40 PM

It would help if you would post some pictures.  It sounds like you have two problems.  First you have some binding.  There is some adjustments that can be made to the worm gear to back it off.  If it is too tight you will experience what you describe.  You may have to push it back manually to effect the adjustment.  Be smart with any force you apply.

 

Second item is the plastic gear may be stripped, stripping,  or slipping off the splines in the middle of the gear.  You can confirm this visually.  Fix here depends on what the issue is.  Align it so the splines are fully engaged, or glue it, melt it, use AL foil.  The least destructive method is best.

 

A picture would really help as it has been sometime since I went through mine.  One other item to look for is cracked plastic which can cause the system to shift under force.




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