Tonight I noticed my EQ6 mount head, the very top part where the dovetail bar connects into, is moving in a sort of up and down direction along the line of the dovetail bar.
The attached image tries to illustrate what I mean.
It's causing quite a bit of wobble in the scope when slewing.
What is causing this to come loose, and how do I tighten it back up again?
If it's moving up and down in line with the counter weight bar there isn't a problem, something is loose. But if it's moving left/right then there is. bearings...
This may be backlash or a worm gear meshing issue.
Remove all loads froms the mount, lock the clutches and try to move each axis back and forth by hand, try to judge where exactly the movement is.
My EQ6 has a fair bit of backlash in DEC, it had a lot of backlash in RA as well but I was able to adjust it out.
Another thing to check, is it just the dovetail foot coming loose? This can be easily fixed by tightening the three grubscrews around the base of the dovetail foot.
That cup that the CW bar extends from has 3 holes in it leading to 3 grub screws that if loosened will allow you to twist the cup and thereby apply more (or less) tension to the declination axis bearings. You might want to experiment there. Do this adjustment with the dec lock off.
Hi Mike, EQ6 Well I've had one to bits. 2 things to Check. First it could be a loose grub screw which holds the dovetail bar holder in place. If it is this it is worth removing the grub screws and tapping the holes out to the next size and inserting proper bolts.
If it is a backlash problem you will find a small hole in the front and back of the base plate undr the holder where it spreads out. You need to loosen the main hex headed screws in the top plate of the motor housing and adjust the tiny set screws to tighten the rack and pinion gears then retighten the main screws. Don't tighten the tiny screws much, just enough to remove the backlash.
Good luck. Prety bullet proof mount and easy to adjust.
And if for some strange reason, you ever decide to take the large gear off the square aluminium motor mount, make bloody sure you undo the tiny little grub screw hidden under the gear before you try and undo the big SS bolt that holds it on. Failure to do this will see you tearing the end of the bolt off.
Or in your case with play in DEC I guess this image explains what you need to do.
It's worked for me and there is no play left at all. Just remember to test it right after you adjusted these small screws. I've found that if you tight them a bit harder than required there will be this weird sound when the head rotates.
To test it turn your mount on, set it to the highest speed and using all four directions buttons on your EQ6 had control try to rotate at least 90 degrees from your home position.
hope it'll help because I know how it can be annoying when play is noticeable.
P.S. If it's just a top dovetail head play then there are thee top screws located in holes that need to be tightened.
Last edited by ozstockman; 18-07-2008 at 05:31 PM.
ok thanks for all the advice. So the 3 grub screws for the "dovetail foot" as i'll now call it, what are the 3 flathead screws directly beneath each of them for?
Do I have to adjust them first?
I don't have an alan key that fits the grub screws right now so will have to head to the h/w shop.
ok thanks for all the advice. So the 3 grub screws for the "dovetail foot" as i'll now call it, what are the 3 flathead screws directly beneath each of them for?
Do I have to adjust them first?
I was wondering what they are for too but after I removed them I could not find that anything changed.
Anyway there is no connection between them and the dovetail foot. If you remove the dovetail foot you will see it.
Quote:
I don't have an alan key that fits the grub screws right now so will have to head to the h/w shop.
I've found out that a set of keys that usually can be found in Chinese shops for $2-3 has all required alan keys for Skywatcher mount.
ok thanks for all the advice. So the 3 grub screws for the "dovetail foot" as i'll now call it, what are the 3 flathead screws directly beneath each of them for?
Do I have to adjust them first?
Those 3 flathead screws provide access to 3 tiny grubs screws. These grub screws lock the nut that secures the top DEC casting to the DEC shaft. Generally you don't need to touch these.
Quote:
Originally Posted by iceman
I don't have an alan key that fits the grub screws right now so will have to head to the h/w shop.
The allen key for the dovetail foot grub screws is 2.5mm. I got a set of allen keys in a pocket-knife type housing from Bunnings and they've been OK.
BTW, I've got the DEC axis of my EQ6 apart at the moment, as I couldn't eliminate backlash to my satisfaction. Turns out the worm gear bearings are very rough. I think they were over-tightened at the factory resulting in damage to these small bearings. Anyway, I got new, good quality NTN bearings this morning and I hope to have the EQ6 up and running perfectly by the weekend.
EQ6 mount head movement?
