View Full Version : EQ5 woes
6th of April 2009 (Mon), 04:50
Anyone here using an EQ5 mount? I've got one and since servicing it I've deveoped a problem that I can't see to resolve.
Hard to explain, but basically when I put a counter-weight on the shaft it causes the RA axis to push down on the RA worm drive, and this pressure makes it very hard for the motor to turn the mount, and it causes "current overload" warnings on my hand-controller.
Even when the scope is balanced this happens. Thin chance I know, but has anyone out there with an EQ5 ever had this problem and knows how to fix it? I have some ideas, but not sure it's going to work. :(
6th of April 2009 (Mon), 08:10
I'm not the guy to give advice on this particular mount but what you're describing sounds like something in your hardware isn't supporting the weight. I'm referring to bearings, lock down nuts/washers, etc. Once the worms are tightened down properly there should be no way to cause additional stress or binding upon them. This is critical to proper worm gear adjustment, as you are well aware. Somewhere there's some give where there shouldn't be. If needle bearings(or standard type) inside are failing this would cause give on the axis allowing it to tilt just enough to put pressure on the gear and of course would alter tracking and have a negative effect on the gears and motor over time.
That's where I would start but it would help to talk with someone who has disassembled one to get the best possible troubleshooting approach. Tech support?
6th of April 2009 (Mon), 08:29
What did you do to 'service' it. I was quite surprised when I tinkered with mine, to see if I could improve the dec clutch operation, just how small the gears and things are in these things compared to the weight of some of the gear I have put on the top of it. There are bigger cogs in my sons Lego Technics motors :-) Scared me enough to quickly put all the covers back on a leave well alone and to convince me that a sturdier mount is going to be on the cards at some point.
6th of April 2009 (Mon), 10:22
Thanks guys, I'm wondering if there's play between the "shell" and the bearings which is causing this tilt, and how to remove this play.
Chris, I just took it all apart, cleared out all the sticky gunk which was used to grease it and re-lubed it with Silicone gel. It's so much smoother with just that alteration, but unfortunately I've obviously not quite put it back right, and I find it very hard getting the right adjustment so that there's little or no axis slop, but keeping the gear movement slick and smooth. Seems there's either loads of slop and it moves freely, or no slop and it won't move because it's too tight. (This is before I put weight on the shaft and cause the gears to bind and seize up all-together!!)
I'll get there...it's become my challenge. It basically means I can't use my 5" 1200mm refractor at the moment is all...I can still mount my camera with a lens, or probably still use my 66mm as it requires little in the way of a counter-weight.
6th of April 2009 (Mon), 14:01
did you refer to the pictures contained on this site to see how it all goes together?
I found them very useful (and I took pics at each stage with my camera just in case).
7th of April 2009 (Tue), 02:39
Yes thanks mbscad, I used that site to service my mount. I don't know why when I put it back together there seemed to be some tolerance along the RA axis though. This tolerance was causing the entire RA part of the mount to wobble slightly, and push the gears together when the counter-weights were added.
However, had another fiddle last night and tried something. I've got some thin aluminium tape, which I used small bits of to sit under the large bearing in the RA axis, holding it a bit tighter. I also adjusted the position of the RA worm drive slightly, moving it fractionally away from the RA gear. While there still seems to be some wobble, and a bit o axis slop, the mount at least now runs when fully loaded. (And still runs when I add extra weight onto the counter-weight shaft.)
So fingers crossed I'm now up and running again. :)
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