Jammed RA gear on EQ-1

[mag10]

Hello from Canada everyone!

I think I've just proven the old rule "buyer beware".

Even though I have 4 new 'scopes including a C8 CGEM, I'm still a relative newbie.

I just bought a used Skywatcher EQ-1 mount with RA motor for my 102mm refractor from a "guy" who posted on a local astronomy site. Well it turns out that the RA gear is jammed solid. The motor "ticks" over inside the box, but no turning of the RA gears. Same thing when I try manually, even with a lot of strength.

The RA mount actually turns (along with the graduated disc), but not the gear underneath, nor the pinion gear to which it's attached, therefore no control for tracking or photography.

When I e-mailed the seller, he fobbed me off by saying it's "normal", that the pinion screw has reached its end, and I just have to "unscrew" it and it will work. I mailed him back to tell him that this kind of pinion screw has no "end", it's just supposed to turn and engage the gears on the RA mount.

I've yet to receive an answer on that one (three days gone).

Any ideas on how to unjam these gears, or was I completely had?

Thanks,

Jerome Tremblay

Montreal

[david o]

Hi Jerome, first up... welcome to SGL

Not got an EQ-1, but some thoughts come to mind.

1 - Is there a tension adjuster for the RA worm gear? Could it be that it just needs tweaking to engage with the driven gear inside?

2 - Are there plastic gears somewhere in the drive-train? Could one, or more, have been stripped?

Sorry can't be much more help

[steelfixer]

Hi Jarome.

I know very little about your mount but as an engineer my solution would be to strip the whole thing down and go through it stage by stage.

If this process seams daunting to you I would advise you take photos before each step and then you will have a reference for when the time comes for you to reassemble the mount.

Just a thought.

[Bazzaar]

When you tried to manually rotate the RA drive shaft did you loosen or un-attach the motor drive? You can not rotate the motor drive output, it may be that stopping it not a seized RA gear.

When you were looking to see if the motor drive moved the RA are sure you gave it enough time? they move incredibly slowly.

Regards

Barry

[jgs001]

There's a plastic flexible joint thing between the motor and the RA Axis. Uncrew the thumb knob and remove the motor completely (there's an allen key at the centre of the Alt adjust point also). Without the motor attached can you turn the RA Axis ?

When the drive is active, the amount of motion is barely noticeable if you're watching it. You'll need to activate it and leave it for 10 to 15 minutes and check again to visibly see the motion, the other option would be to mount a scope and go to a star low in the east... use a high power, and set the motor running... If the star doesn't drift out of the FOV in quick order... it's tracking ok.

I have an EQ1 and motor drive for very widefield photography.

[mag10]

Hello all, and thanks for the quick responses.

@ David O:

1- There are 2 screws holding the worm gear assembly to the mount. I loosened them almost to the point of removal, with no apparent change;

2- Both gears are all metal with no teeth missing;

@ Steelfixer:

Daunting indeed! The whole unit seems sealed. In any case this kind of surgery is probably well beyond my limited mechanical skills!

@ Bazaar & jgs001:

I did not loosen or detach the motor. The allen key required to do so is positively minuscule, and not present in my (very) basic toolbox!

I will try what you suggest and try tracking something. (I had not thought about the slow speed of the drive-motor), but my manual exertions give me a nasty feeling that the "main gear" (the one with the teeth that engages the worm gear) is somehow seized-up somewhere inside the sealed mount.

If the tracking test does'nt work, I'll take the mount to my local astronomy shop, and see if the guys there can help. But like I said, I have a feeling I just bought myself a spare-parts collection I can cannibalize for when I finally buy myself a NEW EQ-1!

(I really like the way my 102mm refractor looks on this mount. It's a nice lightweight tracking combo for when I can't be bothered to set-up my big hulking C-8).

In any event, this whole experience will have made me discover the fine people at Stargazer's Lounge. So it's not a total loss!

Thanks again friends,

Clear skies!

[jgs001]

Try just loosening the ra axis attachment from the plastic fixing, if you undo that knob enough, you should be able to turn the axis without problem, without completely removing the drive.

[mag10]

Thank you very much to all. I will try everything suggested and give you all an update on how it went.

Note:

I'm not just an astronomy newbie, sort of, (95 books, 104 DVDs, 4 telescopes, but all gathered in just over a year), I'm also an internet newbie, sort of, (50 years old, working on an office computer for half that time, but no home internet until a month ago).

What I'm trying to say is that I'm simply overwhelmed that I can be confronted by a technical problem in Montreal, and in less than 6 hours, have advice from 4 English Counties and Spain!!!

Most of you wil be thinking "where have you been for the last 20 years?".

The honest answer is "just getting by".

But my newfound passion for astronomy has widened my view more (much more) than "just" enjoying the night sky and figuring out my place in the universe. It has given me a most unexpected gift:

The realization that everyone on Earth is in fact, a neighbour and a friend.

I guess than in my own limited way, I've just experienced what so many astronauts have known for so many years:

In the end, the exploration of space is much less about what's "out there" than about a new appreciation for the incredible treasures "down here".

Okay that's it.

Enough maudlin muddle!

[brantuk]

Hi Mag - well thats a right rapid update you've had over the last year or so. Astronomy can be overwhelming even for people accustomed to the technology so you're doing well so far. Just take it a step at a time and you'll soon build on your knowledge and become proficient so long as you don't try to rush it all at once. Hope you enjoy your time here with us at SGL

[steelfixer]

Hi again.

Another thought.

If you are trying to make the motor turn by rotating the mount you will have no chance because of the gearing.

If you think about it the motor will probebly turn 100 may be up to 1000 times for every revolution of the mount. With this sort of gear reduction you will never move it from the mount end in fact you will more than likely shear off the drive shaft on the mount.

A final personal way of looking at things is 'if it was made it can be mended.'

[mag10]

OK I'm doing a `tracking" test right now (on two nail heads on a niehgbours roof!).

Back in 15 minutes...

[mag10]

Well guys,

Don't I feel the fool.

The thing works after all.

Maybe I should have tried it before crying Wolf.

I'm both relieved that I did'nt buy a dud, and so very sorry for wasting everyone's time.

Thanks for your time and concern.

Jerome

[jgs001]

Jerome, glad it's all working.