Re: AP900 yellow light

Jeff Young <jey@...>

Joe --

The instructions on the website for adjusting worm gear backlash will
show you how to do it.

Go to the AP website and click on Technical Support in the left-hand
banner. There are links there for how to remove the backlash on the
various mounts. Note that you don't really need the hammer anymore
(particularly if you have the spring-loaded motor brackets). You can
just loosen the motor box, push it into the worm hand-tight, tighten it
back up again, and then make sure that you can move the gear on the end
of the worm by hand.

-- Jeff.


From: [] On
Behalf Of joe.breault
Sent: Wednesday, October 17, 2007 3:20 AM
Subject: [ap-gto] Re: AP900 yellow light

--- In <>
, chris1011@... wrote:
> In a message dated 10/15/2007 10:13:00 AM Central Daylight
> joebreault@... writes:
> > Hi all,
> > Just joining the group after getting an AP900 from the 2007
> > Astromart. Got delivered
> > this past week. I got the dovetail for my scope
this weekend
> > and mounted it
> > all up on the AP900. When I plugged in the power source the
control box
> > light would just
> > turn from the initial red to yellow indicating the motor
> >
> > The manual indicated the most common reason is an unbalanced

scope. I have
> > no experience
> > doing this, but did spend hours on various balances and it
to be
> > balanced in the two
> > axes from what I could tell. Even taking the scope and
off, the
> > light still turns yellow
> > with an empty mount. This is the same regardless of how
loose or
tight the
> > clutch knobs are.
> >
> > I checked the power source and it is a full 12V via a meter
the cord end
> > that plugs into the
> > mount. ALso got a second battery source to double check and
problem with
> > the yellow
> > light after a moment of a faint sound then a click.
> >
> > Wondering if any of you had any trouble with the yellow
light or
any tips
> > how to overcome
> > this. Thanks
> > Joe
> > New Orleans
> >
> Yellow light means motor shaft is not turning at the commanded

sidereal rate.
> You need to find out why the motor is not turning (jammed gear
> broken wire leading to the motor). Did you buy this mount
used? If
so, the
> person who sent it to you may not have packaged the mount
The motor box
> may not have been protected in the packaging, so that it has
into the
> worm wheel, thus causing the worm to not turn.
> Jammed gear is easy to determine. Remove the motor gearbox
and try
> turning the large spur gear with your finger. If you cannot
it, neither can
> the motor. If this is the problem, then it is easy to fix.
contact Wally
> or Howard here at AP (call any time between 9am and 5pm CDT)
they can
> walk you through the procedure. Once you have done that, you
know a lot
> about the mechanics of your mount, and you will feel confident

about making any
> kind of adjustments in the future to keep the mount humming
> Rolando
> **************************************
Thanks Rolando. It is a used scope sent to me this past week,
though just a few months old from the 2007 run.

I talked to Howard today, and when I got home tonight I followed
directions which you also gave:
1. The side of the RA motorbox was removed by taking out the 6
small set screws with a tiny allen wrench
2. The large metal spur gear would not move using my fingers
trying to force it to move. This was then unscrewed (unscrewing
screw that holds it in the center of the gear). The center screw
large metal spur gear were removed from the motor box
3. The white telrin gear attached to the motor moves easily like

butter, just as Howard described.
4. HOWEVER, the small metal spur gear near the worm cannot budge

at all, unable to move it. This must be the problem with this
having somehow been jammed into the worm when it was shipped to
(even though it shipped in foam padded scopeguard cases and
well packaged...but who knows what UPS ground may have done with
5. Now waiting to call Howard back tomorrow to find out how I
adjust it
Thanks for the quick response
Joe in New Orleans

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