AP 900 GTO CP3 Dec Motor Stall and Worm Gear Adjustment?


Roland Christen
 

In a message dated 7/7/2008 6:06:10 PM Central Daylight Time,
hsielski@... writes:


After about 4 or 5 hours of observing and slewing around, the Dec motor
stalled and the yellow light came on. I'm thinking that this may be due to
my battery voltage getting low (I have one of the little Kendrick batteries
that you used to sell) possibly combined with a slight "tightness" on the
worm gear mesh (since it always seems to be the Dec axis, and you recall I
had a slight problem with this a couple of months ago).
Those batteries don't last very long. What you need is a big marine battery
from one of the big box stores. Cost is around $45 to $65, so it's not
expensive. Reason why it seems to stall when using Dec is that RA is always powered,
running the mount in sidereal mode. When you add Dec, you are increasing the
current draw because now both axes are drawing power. This may put it above the
threshhold of the battery, where it then begins to die.

Rolando


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Roland Christen
 

In a message dated 7/7/2008 7:14:55 PM Central Daylight Time,
hsielski@... writes:


Thanks! I think I'll try upgrading my battery before I start messing with
the worm gear adjustment. Do you think 35AH is big enough (just mount, no
camera/dew heater)?
35AH will give you about 35 hours of tracking and slewing.

Rolando


**************
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fuel-efficient used cars.
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Hank Sielski
 

Hi Howard,

I just got back from the Golden State Star Party and had a couple of great
nights with my AP155 EDFS and the AP900 GTO CP3 (no 594 from early 2006). I
finally managed to see all the Messier and Caldwell objects (and a bunch of
other stuff) around Sagittarius and Scorpio, but I had a slight problem with
a stall in the Dec motor at the end of each night.

After about 4 or 5 hours of observing and slewing around, the Dec motor
stalled and the yellow light came on. I'm thinking that this may be due to
my battery voltage getting low (I have one of the little Kendrick batteries
that you used to sell) possibly combined with a slight "tightness" on the
worm gear mesh (since it always seems to be the Dec axis, and you recall I
had a slight problem with this a couple of months ago).

Until recently, I've never had a problem going even a couple of nights with
this little battery (I don't image or use a dew heater), but I'm thinking
that after 2 plus years it may be getting a bit tired and it might be a good
idea to replace/augment this battery with some kind of heavy duty marine/AGM
battery with more capacity. Do you have any recommendations here?

On the worm gear adjustments, I went to the web site and it seems that I
can't see where Wally may have updated the 900 instructions for the newer
motor brackets/configurations yet. Do have a link to them or do you think
it would be OK to use the ones for the 1200 in the mean time?

Thanks for the great products and support!

Hank in Sunnyvale


Hank Sielski
 

Rolando,

Thanks! I think I'll try upgrading my battery before I start messing with
the worm gear adjustment. Do you think 35AH is big enough (just mount, no
camera/dew heater)?

If I still have trouble, I'll talk with Howard and Wally...

Regards,

Hank

On Mon, Jul 7, 2008 at 4:42 PM, <chris1011@...> wrote:

In a message dated 7/7/2008 6:06:10 PM Central Daylight Time,
hsielski@... <hsielski%40gmail.com> writes:

After about 4 or 5 hours of observing and slewing around, the Dec motor
stalled and the yellow light came on. I'm thinking that this may be due
to
my battery voltage getting low (I have one of the little Kendrick
batteries
that you used to sell) possibly combined with a slight "tightness" on the
worm gear mesh (since it always seems to be the Dec axis, and you recall
I
had a slight problem with this a couple of months ago).
Those batteries don't last very long. What you need is a big marine battery

from one of the big box stores. Cost is around $45 to $65, so it's not
expensive. Reason why it seems to stall when using Dec is that RA is always
powered,
running the mount in sidereal mode. When you add Dec, you are increasing
the
current draw because now both axes are drawing power. This may put it above
the
threshhold of the battery, where it then begins to die.

Rolando

**************
Gas prices getting you down? Search AOL Autos for
fuel-efficient used cars.
(http://autos.aol.com/used?ncid=aolaut00050000000007)