EQ6 Damage? - Ouch!

[Monmouth3817]

Hello all,

Last Saturday morning while setting up my scope for our local society’s Open Day, I had the misfortune of my EQ6 Pro head tip off its tripod base and hit the concrete ground, complete with one counterweight – lucky no scope fitted! This was caused by one of the tripod legs not being tighten up correctly, and the centre tripod bolt not being secured as well as I thought. The weight of the head collapsed the north facing tripod leg by about an inch and the resulting momentum allowed the head to fall forward and off. I normally have a strict protocol when it comes to setting up the mount/telescope, but this time I just forgot to tighten things up correctly- Doh! Please don’t make the same mistake.

The tripod was sitting at almost its lowest setting, but that’s still a good two and a bit feet off the ground. Anyway, after a few swear words later, the only damage was scuffed paint to the counterweight, a half snapped DEC knob (though this is still useable) and a few paint scrapes on the head and on the motor caps (those little black/bronze colour discs near the motors. Luckily it fell onto the side which didn’t have the power or hand controller sockets.

After licking my actual and mental wounds I re-mounted it I was surprised to find that the mount worked fine all day long. The motors sounded exactly like before and the control unit worked ok with no problems.

Later I took some time to look at the head to see what possible damage there could be. Here’s what I found, and any feedback would be great.

1): When the RA knob is locked (fully on) I can physically move the mount in RA back and forth, probably about two or three millimetres – I’ve not measured it exactly but this wobble is more than what it had been before – I assume this is backlash. When I point at an object, and then press the RA button on the handset, there is a short delay before it moves – about a second or two - again this delay is greater than it had been before. I’ve not had an opportunity to try and autoguide with the mount yet so to ascertain if there are any issues there.

2): The stainless steel counterweight bar wobbles ever so slightly when it is locked in its extended position (and with no weight attached). This didn’t happen before.

3): The cone like collar at the bottom of the DEC shaft (where the counterweight bar can be stored in is also slightly wobbly. Maybe the stress of the impact has dislodged the grub screws. However, when I looked inside the holes with a torch to look at the grub screws I couldn’t see what size allan key I’d need – anyone know what size? I tried using some sizes I thought were correct, but couldn't get anything to budge.

With the mount being quite old (2001 vintage), perhaps different types of screws were used than what’s used now,

I’ve had a look at AstroBaby’s website regarding stripping/maintence of the EQ6, but before doing anything rash, and making things worse, I’d love to hear what others think I should do.

I’ve had this black coloured EQ6 since September 2001 and it amazes me just how rugged they are, even after this recent mishap. I upgraded it to GOTO in 2008, and it has been a great workhorse with my telescopes – I suppose it’s the astronomical equivalent of the proverbial brick toilet.

Regards

Monmouth3817

[Astro_Baby]

Heres my two penneth....

1): When the RA knob is locked (fully on) I can physically move the mount in RA back and forth, probably about two or three millimetres – I’ve not measured it exactly but this wobble is more than what it had been before – I assume this is backlash. When I point at an object, and then press the RA button on the handset, there is a short delay before it moves – about a second or two - again this delay is greater than it had been before. I’ve not had an opportunity to try and autoguide with the mount yet so to ascertain if there are any issues there.

Almost certainly the worm gears have shifted a bit. Probably the worm carrier moved under the impact. These things dont need much to upset them in this regard. Everything you explain there tells me its either a worm to ring gear issue OR a worm to spur gear issue. Take a look at my guide on tuning the worm gear. Its a fiddly job but doesnt need a mount strip. Just a few allen keys and some patience. It could also be the motor spur gears to worm gears but this is less likley I would think and in any event not hard to fix.

2): The stainless steel counterweight bar wobbles ever so slightly when it is locked in its extended position (and with no weight attached). This didn’t happen before.

3): The cone like collar at the bottom of the DEC shaft (where the counterweight bar can be stored in is also slightly wobbly. Maybe the stress of the impact has dislodged the grub screws. However, when I looked inside the holes with a torch to look at the grub screws I couldn’t see what size allan key I’d need – anyone know what size? I tried using some sizes I thought were correct, but couldn't get anything to budge.

2 and 3 are most likley caused by one of two things. EITHER the cone shaped collar has gotten loose (easily fixable) or something horrid has happened to the main shaft ( a nightmare ). Lets assume the best scenario.

The collar is held on by three small grub screws situated at equal intervals around its circumference. These must be slackened off. Not too much or else they fall out and are hard work to get back in again. The counterweight collar then unscrews.

I cant tell you the grub bolt size as I dont have an EQ6 on hand to check. They are allen headed though so it sounds like a trip to Halfords for some metric allen keys. If by lucky hap your mount shipped with an allen key which you didndt know what to do with its probably the same size as these bolts have. WARNING the supplied allen key is as soft as cheese and these grub screws are usually installed by the Incerdible Hulks really strong brother.

Get the collar off and inspect - might just have gotten the wobbles. My strip down guide covers how to get it back on with the right tension. You'd have to read it as I cant remember Also with the collar off take out the taper bearing underneath the collar and have a look. It should drop out easy enough with the collar removed.

If you get it off use a bit of thread lock when you redo the grub screws. After its been replaced check the grub screws frequently at firts. They have an annoying habit of working loose even with thread lock but will eventually settle down and stay tight.

If the main shaft has a problem its a bit of a pain and probably expensive too. Only mount I have seen bust the main shaft is a CG5.

The clutch lever being busted....well this just might be your lucky day. I have a spare clutch assembly from a CG5. The lever is the same. PM me and I will give you a price for it.

Hope thats all of some help.

[Monmouth3817]

Thanks Astro_Baby for your very useful info.

I'll take a look at the mount this weekend and see what I come up with. I've already got some metric allen keys, so I'll have another go at the mount after re-reading your pages about the EQ6. I may take you up on the offer of the clutch lever, but I've got a mate who may be able to do something for me. If not, I'll come back to you.

Cheers

Monmouth3817