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Strange heq5 pro dec motor problem. Please look.

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#1 neptun2

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Posted 18 June 2009 - 11:28 AM

I have finally received my heq5 synscan upgrade kit and put all things together but i have strange problem with my DEC motor. Both the RA and DEC motors have one big wheel and one small with axis going through it. This axis brings the movement to the small wheel then small wheel to the big wheel. In my case the axis in the dec motor is just not tightly connected to small wheel and the axis rotates in the small wheel without rotating it. Here is a movie showing the problem. There is no set screw or something else to help me to tighten the axis and small wheel so i will return the kit. My question is - have you ever seen such defect with these mounts? Is it common? Should i consider the possibility that all motors of heq5 pro or eq6 pro can defect in this way after some time of usage? Thanks in advance.

Edit: Here is a longer version of the movie showing that the gears are ok and can easily be rotated manually. Also it is shown behaviour at different speeds of slewing.

#2 John Carruthers

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Posted 18 June 2009 - 12:19 PM

The motor pinion has come loose, they are often just superglued on. Clean and de-grease the shaft thouroughly and give it a slight rough up with fine abrasive then glue the gear on the shaft. You can cross drill it once set and fit a small pin to prevent it happening again. Or drill/tap the gear and file a small flat on the shaft then fit a grub screw (2 might be better at 90 degrees).

#3 Timo Kuhmonen

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Posted 19 June 2009 - 12:58 PM

thanks for info, my upgrade kit for HEQ-5 is on the way at UPS. Hopefully I do not have this problem...

What is the diameter / material of motor shaft ?
(just to ensure what tools may be needed for fixing this)

#4 neptun2

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Posted 19 June 2009 - 01:18 PM

Unfortunately i already returned the dec motor for repacement so i can not measure the diameter. The material of motor shaft looks like steel. I made search through the cludynights archives for 2 years back in time and saw only 2 similar problems. So it is not likely for you to have such problem. I even managed to pull the small wheel out of the shaft fairly easy. The shaft is smooth and there were no signs of glue. So i think that the small wheel was warmed up and coupled with the cold shaft with the idea that after the wheel becomes cold again it will shrink and make strong connection with the shaft. Probably in my case the wheel opening was just too wide. Another possibility is that they use some kind of glue but someone in the factory just forgot to apply it to this motor. This seems more unlikely to me. I also thought to use some kind of glue but i just can not be sure that it will be strong enough so i decided to not risk my warranty. Unfortunately now i will have to wait at least 3 weeks until the motor gets back to opticalvision, they inspect it, fix it or replace it and send it back to me.

Edit: Do somebody have any experience with opticalvision's warranty terms? They are not working directly with customers so i am asking the dealers here at CN.

#5 Kaizu

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Posted 19 June 2009 - 01:38 PM

Normally the shafts are made of steel and the gears are brass. The small gear has probaply been fixed by tight fit. It can be loosen if the fit has been made poorly or if the gear has cracked. The glue is poor solution, because it reguires small gap between the parts and that means eccentric gear and one small wave to the periodical error curve. Of course the glue is better than loosen gear.

Kaizu

#6 neptun2

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Posted 19 June 2009 - 02:08 PM

The gear was not cracked. I carefully looked at it. Probably really the fit has been made poorly.

#7 heatmizer

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Posted 19 June 2009 - 05:36 PM

It just needs some loctite on the small gear

#8 neptun2

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Posted 20 June 2009 - 02:25 AM

Do you think that loctite will be strong enough? During goto the initial axle load seems to be high. I am not sure if the glue will be strong enough. I hope that they will fix it. If not - i will try different options that all of you told me.

#9 Kaizu

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Posted 20 June 2009 - 04:57 AM

Loctite has several different glues, also for metals.
Google may know.

Kaizu






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