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ES AR 102 focuser problem

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#1 christheman200

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Posted 11 August 2013 - 10:26 AM

Long story short, I held up on getting the C 102 GT until Starfest this year to see if I could find my own 4 inch refractor there and ended up winning the last (grand) prize of an ES AR 102 (F/6.5). We took it out of the box in our hotel room and realized that the focuser was sticking pretty badly so after some googling I found that this model had some production issues with bad of users in them, as well it has no white markers on the draw tube. With the tension knob loosened all the way, the coarse wheel is very hard to turn and the fine knob is still quite hard to turn. Are there any ways to fix this? Some people mentioned screws above the focuser. I would rather not have the scope gone for four months while ES tries to fix this for me.

#2 rigelsys

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Posted 11 August 2013 - 10:45 AM

perhaps a moonlite or FT focuser would be a good investment of your savings?

#3 christheman200

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Posted 11 August 2013 - 10:46 AM

No, I will not spend any money to make this scope functional.

#4 Don Taylor

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Posted 11 August 2013 - 10:55 AM

Call or e-mail ES. They should make this right.

#5 T1R2

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Posted 11 August 2013 - 01:13 PM

there are two different size screws on the gearbox underneath, one on the outside closet to the wheels is a small hex key that works the fine adj, its too tight, back it out and just snug it, the coarse knob can be adj. by the larger tention screw in the center closest to the diagonal, the lock screw is in front of that and should not be engaged when moving the drawtube in or out. Once you get that adj. the default setting on you tention knob should work for most of your 1.25" ep's, and just a slight tention when viewing at the zenith with heavier ep's. Let us know how this works for you. This is an easy fix and does not require you to send the scope in.

#6 christheman200

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Posted 11 August 2013 - 04:19 PM

Nope, didn't work. This has to do with the tension inside the gearbox thingy in the focuser.

#7 christheman200

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Posted 11 August 2013 - 04:30 PM

Could someone please link me to a guide on dissasembling this explore scientific focuser? There seems to be a few discrepancies from other similar focusers.

#8 PeterR280

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Posted 11 August 2013 - 04:55 PM

I'd be careful about taking it apart. They are hard to put back together if you haven't done it.

#9 JimT

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Posted 11 August 2013 - 05:05 PM

I would just get Explorer Scientific to replace it. It is new under warranty right? They replaced mine inside of 4 days.
All I had to do was tell them. It was easy and they were more than happy to help me out. They have good customer service.

#10 christheman200

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Posted 11 August 2013 - 05:09 PM

I will if I can't get this fix to work. I can't figure out how to get the slow focuser back inside of the focuser system though.

#11 christheman200

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Posted 11 August 2013 - 05:19 PM

Again, anyone know how to disassemble/assemble/adjust this focuser?

#12 christheman200

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Posted 11 August 2013 - 08:53 PM

With the slow motion knob removed from the focuser it turns very smoothly... IMO as good as a feathertouch, but with no slow motion knob it might be hard to get the perfect focus. Certainly better than the average single speed crayford focuser. It can hold an eyepiece without slipping but certainly couldn't hold a dslr.

#13 T1R2

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Posted 11 August 2013 - 10:07 PM

Sorry it didn't help, BTW the white painted on graduated scale wears off, mine started to go after a couple of sessions so I just took them the rest of the way off with some duct tape and fingernail.

#14 christheman200

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Posted 11 August 2013 - 10:23 PM

Can't figure out how to reattach the slow mo knob still. Just attached the scope onto a tripod by taking off the dovetail bar and found that past 45 degrees the focuser would slide to the bottom with my lightest EP, this is with the slow mo knob off. Reattaching the knob and disengaging it would allow me to still have smooth focusing and not have it slide to the bottom.

#15 christheman200

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Posted 11 August 2013 - 10:38 PM

Ok, I guess I should just ask this: how do I reattach the slow mo knob to the focuser. There.

#16 T1R2

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Posted 11 August 2013 - 10:53 PM

if the lock screw is not disengaged fully it will cause the drawtube to stick, the best way to check this is to remove it completely its the smaller diameter one that is long and has a nylon tip the tention is the larger diameter one that is short, if somebody before you had it and switched it around it will cause problems, the tention one goes in the hole closest to the diagonal, the locking knob goes in the other, also adjust the hex screws on the top and bottom of the focuser, the black and chrome ones, back each one out a little and just finger snug each one in turn like the lug nuts on a tire. Next adjust the hex screw underneath on the gearbox and the one next to it its a flathead screwdriver. Then add a little tention with the tention adjustment screw and replace the lock screw so its head is at least 2-3mm below the tention screw. If this doesn't work, you have a bad focuser and can then send it to ES.

#17 christheman200

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Posted 11 August 2013 - 10:59 PM

No that isn't my problem. I decided to take apart the focuser to adjust the internal 10 to 1 ratio mechanism but couldn't get to it and now I can't figure out how to reattach the slow mo knob, which is the knob marked "one" in the second diagram on this page: http://www.opticstar...eneral.asp?p...

#18 T1R2

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Posted 11 August 2013 - 11:05 PM

Did you tear down your focuser? there are hex key screws that attach the components together. The large wheel has one on the shaft and has to be removed before you start to take the gear assembly off. then the hex screw on the fine focuser, but really you should do as I described earlier, before attempting this. before you go any farther there is nothing in there that can't be adj. by the steps I gave you.

#19 T1R2

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Posted 11 August 2013 - 11:10 PM

I think you should get ahold of Mr. Powell, he is Powellastro on here I believe, he can walk you through the steps, it seems you are on your way to removing the whole drawtube. yikes.

#20 T1R2

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Posted 11 August 2013 - 11:42 PM

Ok, I see what your doing from the diagram, everything is there that you need, just remember that part 1 is the tention adjuster screw, the one with the larger diameter head but short, they have it listed as the lock screw, but its not on the ES models. Are you applying grease or adjusting the nut on the shaft, or both?

#21 christheman200

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Posted 12 August 2013 - 12:22 AM

I was going to simply adjust the tension, and maybe apply some grease but I couldn't figure out how the whole assembly worked as it was slightly different from that diagram and all others I could find. I did check all the lock screw type thingys as well as pretty much every screw on the whole focuser but it still has jerky motion when focusing and can barely hold my ES 82 8.8 at upright and begins to slip too. I fiddled with it for a while and managed to get the smaller focuser knob back on but it just made the motion (far) less fluid, although it allowed the scope to point farther up before slipping but still not all the way up, maybe 60 degrees actually. At this point the focuser seems faulty to me. While I have fiddled with it, these same results were happening before I fiddled with it and were not caused by my investigation. I will call ES tomorrow to get a replacement shipped out, and I will make sure that I don't have to mail this one back first (I've had enough of that nonsense being requested by Orion already) as it just increases the wait time and they've had enough of these problems that they don't need another one to examine for faults. I put it on a tripod and pointed it at Andromeda but the poor focusing made it nearly impossible to see. If I stay up late enough I will point it at Jupiter to see if this stands up to what I think it should be.

#22 T1R2

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Posted 12 August 2013 - 12:43 AM

depending on how far you are away from NW Arkansas, it shouldn't take that long to get either the part or the scope back, a few days journey there a day or two in shop a few days return trip, you could be rollin in a week though it will seem like forever.

#23 christheman200

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Posted 12 August 2013 - 01:00 AM

Toronto, Canada. The problem isn't shipping, it's customs. Getting it to them would probably take about 4-7 days depending on when I ship. And since I've done my research into the problem and have found others with the same problem who have simply shipped it in and got a replacement back in return (all of the people who had this problem just got a replacement part, so shipping the part in wasn't really necessary to achieve the end result) I think that it is only fair that I would be shipped the focuser without having to send the faulty one back. ES should already have enough of the faulty focusers at this point to study and I could just take it into a local astronomy shop and have them confirm that it is faulty if that is why they want it back. If I have to pay for shipping, it will also be a no simply because this was a "gift" scope from ES in a random draw and I don't want to have to pay money to get a scope working that I was not going to spend any money on in the first place.

#24 christheman200

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Posted 12 August 2013 - 11:43 AM

I've been contacted by a member of the forums who kindly got me on my way to a new focuser. He called before I woke up (just now) and now all I had to do was email a service rep my contact/shipping info and I will have a new focuser in new time.

#25 christheman200

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Posted 23 August 2013 - 03:04 PM

A new focuser has arrived and it works perfectly after tightening the adjustment screw a bit.






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