Lightbridge 12" with Argo Narvis

[ENVY]

I've had the lightbridge nearly 12 months and installed Argo and encoders a short while ago.
When you install the encoder's you replace the bolt that goes into the base of the turn table to fit encoder wheel
I now have no tension on the turn table and the slightest breeze the tube spins
Meade use a flat needle bearing between lower and upper plate
Can anyone assist in how I can create more friction to reduce the free wheeling

Regards

Peter

[GeoffW1]

Hi,

After getting this problem on a Dob, after fitting a lazy susan bearing between the 2 halves of the baseplate, I found that glueing a few pieces of dense foam in that space was effective, to create a little drag.

Cheers

[gary]

Hi Peter,

Thanks for the post.

Did your scope also come with a smaller roller bearing along with its associated two
washers? These would normally be sitting on the top side of the base of the rocker
box? (see page 5, step 4 of the Meade LightBridge Instruction Manual).
See http://www.meade.com/manuals/TelescopeManuals/lightbridge.pdf

The reason I ask is that recently I encountered a user's scope where the smaller
roller bearing and washers had not been fitted. What then happens in this instance
is that the bushing that is inside the hole protrudes by a mm or two above the
inside base of the rocker. This then prevents an adequate bearing surface to
be presented to either the original tensioning handle or the replacement timing pulley
which effectively does the same job.

If your scope was not supplied with the smaller roller bearing and washers, I
recommend obtaining one from a bearing supplier and fitting it. They are
inexpensive.

Then with the timing belt still temporarily removed, using the large pulley as a
tensioning handle, tighten the bolt into the threaded insert to achieve the required
friction, before re-fastening the nut on the bottom and re-attaching the timing pulley.

If some small additional tension adjustment is required, on the hub of the large pulley
there is a set screw. Using the supplied long-armed 1/16" hex key,
loosen the set screw just a little so that the pulley can slide up and down on the
bolt but not so loose that it can accidentally rotate and loose reference to the
flat on the bolt.

Now, using a hex wrench, tighten the 1/4" nut that is above the pulley which
will force the pulley to press harder down. Then re-tighten the set screw.

At the best of times, the LightBridge Az axis rotational "feel" tends often not to
have the ideal combination of stiction and friction. As Geoff mentions above, the
addition of some dense foam pads or possibly some virgin Teflon pads in the
gap between the base of the rocker and the top of the ground board may further
assist.

Please don't hesitate to contact us should you require further assistance.

Best Regards

Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place, Mount Kuring-Gai
NSW. 2080. Australia
Phone +61-2-9457-9049
Fax +61-2-9457-9593
sales@wildcard-innovations.com.au
http://www.wildcard-innovations.com.au