EQ2 fell apart last night - I need help!

[teh_orph]

Hi guys,

a bit of help here would be much appreciated...my EQ2 mount came apart last night! I had to pull the whole thing apart in the dark (at 3am) so that the OTA didn't fall off and smash on the floor!

Basically the RA axis has separated, and is now in two pieces. There's a thread on the top of the bottom part, and this appears to screw into the inside of the top part of the mount (which holds the dec axis).

This is the lower part:

The left of the image is the part that screws onto the tripod, the right is the rod around which RA rotates. This would normally attach to the upper section which holds dec.

Initially the thread had dropped into the lower section, and I managed to pull it out with neddle-nose pliars.

Close up on the rod, with the thread at the end.

Here's where I think it should screw in, the inside of the top part of the mount (RA "stop moving" screw on the left; it basically tightens against the RA rod)

If I do this it attaches correctly, assuming I turn it one way. Turning it in the tightening direction gives the same resistance as when the mount was functioning correctly, but turning it the other way very quickly undoes it and it'll fall apart again - the thread is pretty short. I'm not sure how to get it to stay together when rotating the RA axis.

At the other end of the RA rod is a nut which I think if I could hold whilst turning the mount would tighten it - but I can't reach it since it's recessed. Is this the right way to go to sort this, or is it just plain broken?

Does anyone know what the warranty is for this (from FLO) I've had it a year and two weeks!

Thanks for any help

Simon

[JamesF]

Could be that the nyloc nut insert is worn, though I can't see how that could happen in this instance.

Can you get the thread engaged in the nut and then jam the nut with a screwdriver or something similar to stop it turning inside the housing? Failing that I might be tempted to try a thread-locking agent.

James

[Lorne]

Is the hole in jpeg "mount 3" threaded? if it is and it loosens off easily you may have to loosen off the locking nut in jpeg "mount 4" to allow more of the thread on the rod to tighten into the hole. The nut can be loosened by pushing the rod right out with a screwdriver etc. Once the rod is out check that when it does screw into the hole there is no wobble, indicating worn threads.

[Gina]

That's a totally different design from my EQ2 mount (at least mines supposed to be an EQ2 mount).

[teh_orph]

Ok I've pushed the rod out, to see if I can screw it in directly - yes this works and the thread is not worn out. Tightening it up like that works okay. Putting it all back together and using some pliers to tighten it allows it to all hold together again without undoing when I turn the RA axis to the left (the unscrewing direction).

However it's now far too stiff. It's as stiff as if the RA "don't move" bolt is tightened! I think the bolt at the bottom (mount4.jpg) is now causing too much friction against the base. If I loosen it slightly then the thing comes undone again quickly! Leaving it tightened up seems to not be an option, as my RA drive isn't strong enough to turn the mount in that direction.

Err, thoughts?

Gina - do you have any pics of your mount?

[Psychobilly]

For a nylock to "work" you need a 1-2 threads showing through the nylon part... and ideally they are a single use fastener...

BIlly...

[Gina]

Gina - do you have any pics of your mount?

Just looked and it seems I haven't - I''l take a couple - raining ATM. BUT... Just had a closer look and it says "CG-3 Equitorial German Mount"

[teh_orph]

For a nylock to "work" you need a 1-2 threads showing through the nylon part... and ideally they are a single use fastener...

BIlly...

Cheers for the help Billy. I've never heard of a nylock before. Is this what I (or we all...) have? Is it like this? How to Use a Nylock Jam Nut | eHow.com

...so there's a piece of nylon at the back of mount3.jpg, and the screw just screws onto it? Does this mean I don't need to tighten the bolt in mount4.jpg assuming everything's working okay?

If not I'll try the glue or araldite option I think...

And Gina, yeah sounds like a different mount to me! Can I have yours instead if it's not broken?

[Gina]

And Gina, yeah sounds like a different mount to me! Can I have yours instead if it's not broken?

Looks like yours has a proper build in motor drive - mine had a crude add-on MD, hence my own home made drive. I guess I could sell it or maybe keep it to sell with the scope when I upgrade. Not decided yet.

[teh_orph]

Oh the motor drive for EQ2 is a total add-on, and it's not really done very well IMO! There's some bizarre spring thing, and a strange clutch that doesn't really work very well. I think the motor drive might have been a last-minute thing when they designed it... Maybe our mounts are similar after all?

Anyway I covered myself in grease and pulled it apart and reattached it about a dozen times, cleaning it and adjusting the tension in the nut at the bottom. Enough tension so that it doesn't come undone, but not enough so that it's stiff and will undo itself when the direction reverses. I removed two of the washers at the end (they look like they're used as spacers) and loosened it by a millimetre or so and now it seems hunky-dory again. Not a good design tbh.

Panic over!

[Gina]

Well done on fixing it The supplied MD on mine had no clutch at all so no manual fine control with MD attached and coupled up. Very coarse tracking speed control with a thin knurled shaft as a knob. It struggled to turn the mount. My home made version has a finer control for tracking plus fast in/out when not tracking. In use it held Saturn within the frame of my imager for 10 mins at a time. I was happy with that as a first attempt.