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Celestron C14 orange tube

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#1 actionhac

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Posted 22 April 2014 - 04:40 PM

Hi everyone. I now own the C14 that was for sale in the Cloudy Nights classified. Andy and I did some telescope trading until we were both happy.
I thought I would start by fixing the slew problem.
I am finding no technical information anywhere so I'm hoping someone here can help.
The problem appears to be slippage between the worm gear and the fork. I have good movement from the slew motor through the gears and to the worm and worm gear. But the fork is not moving. Is there an adjustment, a clutch I need to tighten?
I can see 3 set screws I can access through this port:

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#2 actionhac

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Posted 22 April 2014 - 04:45 PM

RA motor is driving and moving the fork. The slew motor does drive the fork if the telescope and fork tines are removed. I don't see anything in here to adjust or tighten.
I wish I could find a C14 service manual but I doubt there is such a thing.

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#3 actionhac

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Posted 22 April 2014 - 04:53 PM

Interesting gear arrangement and all seems fine here. RA motor and slew motor both drive the same worm shaft only when the slew motor is running it drives the worm shaft about triple speed. Nothing is slipping in these gears, it must be a clutch or something inside the worm gear under the fork?

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#4 DAVIDG

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Posted 22 April 2014 - 05:47 PM

I have C-14 as well. When the RA lock is on can you turn the forks ? There are couple of possible reasons why the forks isn't turning, the clutch plate is loose or the gear on the end of the worm, driven by the motors is slipping or the gear on the RA motor is slipping or the gears inside the RA motor are stripped.
The slewing motor is DC. When the scope is tracking, power is applied to the DC to lock it so it can't turn. So now the RA motor will turn the worm gear. The RA motor is turning so slowly that is acting like it is locked so when you slew the scope using the DC motor, the motion now goes to the worm. So if any of the gears are loose on their shafts or the gears stripped in the RA tracking motor, power won't be transmitted to the worm gear to move the scope.
So be sure that no gears are slipping when there is some resistance applied to the mount and when you slew the scope that the RA gear on the RA motor doesn't turn as well. If all is tight then it is clutch plate that is slipping and you have to take top off to get to it.

- Dave

#5 gnabgib

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Posted 22 April 2014 - 05:47 PM

It's NOT a slew motor but a slow motion motor to drive object around eyepiece field. Works thru the differential gears (bevel gears). Set up scope and while looking thru it activate the "slew" motor. Object will move slowly around eyepiece field. The levers on each side of the drive base act as a kind of RA lock so they need to be tightened for RA gear to drive fork arms. The DC motor is self locking because it is a high reduction gearhead motor. So it does not use power to lock it. There is no real clutch in these older C14 bases. The locking levers press down in the center of a steel bar that then presses down on two pins on the bar ends. These pins press down against the RA gear hub to create enough friction to drive the scope. If you remove the locking levers (two small set screws) you can then tighten the screws underneath (usually just until you feel resistance) then reinstall the levers with the handle to the right (when facing the lever). This will position them with enough clamping action when tightened to drive the scope.



Hope this helps
Kevin

#6 gnabgib

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Posted 22 April 2014 - 05:50 PM

By the way
The three set screws lock the bearing retainer cap in place so it will not unscrew as the RA axis is rotated.


Kevin

#7 DAVIDG

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Posted 22 April 2014 - 05:52 PM

On my Classic Orange tube C-14 it has slewing motors on both the RA and DEC axis. Both the slewing motors are DC and with two speed setting and also are reversible. So I can SLEW the scope pretty quickly in the FAST position.

- Dave

#8 gnabgib

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Posted 22 April 2014 - 06:03 PM

Just wanted to add that I love these older C14's. They were well made and will literally last a lifetime with a little care so congrats on your acquisition!

Kevin

#9 actionhac

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Posted 22 April 2014 - 06:39 PM

I can move the fork with the 2 RA locks tightened fully, meaning the levers are up against the fork casting.
These 2 locking levers must be locked for the RA drive to work like a C8, and do they also need to be locked for the slow motion motor to drive the fork?
I'm beginning to think all I need to do is remove the lock lever knobs and reposition the knobs to exert more force when tightened fully?
As they are now I can easily turn the levers clockwise right up against the casting which prevents me from tightening any further.
Thanks for the help you guys.

Robert

#10 bob midiri

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Posted 22 April 2014 - 06:57 PM

I thoroughly hope you enjoy your wonderful Classic Orange C14 as I do mine. Bob

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#11 apfever

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Posted 22 April 2014 - 07:01 PM

OH, so YOU got that eh Robert?

I was second in line. I would have loved to have put that with my orange C5 and 8, and I have a couple of words for ya: good job! I hope you get it all fixed up primo. I do have the Ultima 11 black tube here, but I haven't needed to get into the guts - yet. All the drives on mine work. The Millionaire's 8 and the Ultima 11 have DEC drives, but those are only motors on a tangent arm. I can't help with yours, but hope to see it progress to proper workings. Good luck.

#12 actionhac

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Posted 22 April 2014 - 08:21 PM

Its not pretty Neil, it was advertised as a restoration project and it definitely is. I'm grateful Andy was willing to trade telescopes otherwise I could not have done it.
Fortunately the mirrors are OK and the mechanics seem fine, the needed work is almost all cosmetic.
I'm very happy I did get it. I traded 2 telescopes I was not using for something new and exciting, and Andy is equally happy with his trade.
I have some pictures.

#13 actionhac

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Posted 22 April 2014 - 08:26 PM

The serial number is 1 436 8, made the first quarter of 1978 number 436. The RA drive motor date is 7-76.

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#14 actionhac

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Posted 22 April 2014 - 08:29 PM

Mirrors look very good.

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#15 actionhac

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Posted 22 April 2014 - 08:34 PM

The mounting is made up of huge pieces but beautifully designed and made to be able to transported and assembled by one person. This telescope is an amazing engineering achievement.

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#16 actionhac

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Posted 22 April 2014 - 08:36 PM

The mounting is where most of the work is needed. Paint and new chrome.

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#17 TCW

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Posted 22 April 2014 - 08:45 PM

Congratulations! Paint is mostly labor but the chrome could cost a bit. You are reviving my interest in a C14!

#18 orion61

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Posted 22 April 2014 - 08:54 PM

You need to take the RA Lock off (the flipper Paddle) on top front.
There is usually a small teflon or clear tip that wears.
with the flipper paddle off turn the screw down by hand till it contacts then 1/8th turn more, Plac the RA lock back on approx 1/2 way in it's travel possibly a bit less. This is what holds the fork assembly tight with the double drive gear that has the RA setting circle sandwiched between them. If the motor is turning the gear and the fork is not moving this is your problem I am positive of it!
There is also an Allen screw on the back side top that can be screwed down to keep the clutch plate from tilting up as the RA lock applies pressure on most drive bases but a few..

#19 apfever

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Posted 22 April 2014 - 08:59 PM

OOOHH, AAhhhhhh,

The older style locked triangle tripod is great. Much beefier than the newer ones. My old style for my orange C8 and C5 weigh 3 pounds more than the newer locked triangle versions.

Take that wedge off and look under the base. I think you'll see large block castings where the mount holes are. These areas are large enough and strong enough to where you can machine bananana slots into them so the wedge has AZM adjustment like the newer ones. I very much like the way Celestron cast there name into the base on these early versions.
It's fairly easy to wedge the leg tubes, relieve the tension on the end fittings, and take the legs apart, without distorting the pipes. I never found anything other than tension holding them together. I admit to putting a dab of LockTite on mine when I re assembled them. Mine were all for the C8 size.

Rough or not, this looks like a nice project.

#20 actionhac

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Posted 24 April 2014 - 04:33 PM

I tightened the screws under the RA lock knobs (C14 has 2 knobs) a small amount and put the knobs back on and I think this will fix it, thanks everyone I'm glad it was not anything serious.
From what little information I can find about the C14 you really don't need to take apart the base, it should last the life of the telescope. Its all pressed together and a bit difficult to take apart.

Now my next problem is I cannot get the assembled telescope out of my shop. I cannot reduce the footprint radius of the locked tripod enough to get it through the door. I tried mounting the wedge to my Edmund Extra-Heavy-Duty pier and I can't get it through the door ether.
I need a short tripod. JamesE in Canada, James! has one with a scopebuggy for his C14 and loves his setup because he can sit while observing, I like sitting too. I hope he reads this so he can let me know more about his. Does anyone know of a shorter tripod?
Bob you mounted yours to a workmate for a while, was that satisfactory?
I may try mounting the wedge to my hydraulic table which has casters and I can roll the whole scope outside. The table is less than 2ft wide though , I wouldn't want the rig to topple over.

Robert

#21 bremms

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Posted 24 April 2014 - 05:59 PM

Congrats on the C14!! One of my C11 fork arms is peeling funny the rest is good. Just one arm. I like my C11. Probably won't go to a C14. My next big scope will be a premium mirror Newt.

#22 actionhac

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Posted 24 April 2014 - 06:45 PM

I really like the C11 and probably would have eventually ended up with one but the C14 unexpectedly appeared locally.
I can't wait to try it out, I've heard Uranus can be the size of a ping-pong ball.
I've got to make the C14 easy to set up otherwise I'm in trouble. It is possible to remove the OTA from the fork and vise versa by myself but what a headache every time I want to use it.
This tripod shown here would solve all my problems, anyone recognize it?

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#23 bob midiri

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Posted 24 April 2014 - 07:45 PM

Unless u need to travel, I keep mine set up in the garage with each leg on a mini dolly. I wheel it out to my driveway and start observing. Bob

#24 JamesE

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Posted 25 April 2014 - 09:06 AM

Hey Robert,

Congrats on the find!

The tripod was a custom job that came with my C14. It was square steel tubing for the legs attached to a monster aluminum plate. I have some pics if you need them should you want to customize. And then I placed on a scope buggy.

I had to sell my C14 this past year. I still have the scope buggy so if you think that is something of benefit to you PM me and we can discuss.

Cheers,
James

#25 actionhac

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Posted 25 April 2014 - 09:19 AM

Hi James.
Thanks for letting me know, I was afraid it was a custom tripod, I've not been able to find anything like it.

I imagine a lot of C14's are ordered without a tripod with plans to go on a pier in a observatory.

Robert






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