Date   

Re: Fried Mount

Jeff Young <jey@...>
 

Chuck --

It's odd that you and Anthony should have the same problem at the same
time, but yeah, at this point I'd be looking at the Y-cable. If one of
the encoder wires is broken inside the sheathing, or just has a cold
solder joint, then it could make intermittent contact. I assume your
run-aways are always on the same axis (RA)? (If you're getting them on
both axes then it's much less likely to be the Y-cable.)

-- Jeff.




________________________________

From: ap-gto@... [mailto:ap-gto@...] On
Behalf Of ceheber
Sent: Monday, November 26, 2007 7:43 PM
To: ap-gto@...
Subject: [ap-gto] Re: Fried Mount





...then again, maybe not. Turned the mount back on after blow
drying
it and it behaved normally - but, after an hour or so, the mount
started to chatter then run away in RA, it stopped and I got the
"motor stall" message (and power light turns yellow). Doesn't
seem to
be the Y-cable. Both RA and DEC are moving when it behaves. I've
checked the voltage coming from the power supply and it is dead
on
(13.8vdc). Any other suggestions greatly appreciated.

Chuck

--- In ap-gto@... <mailto:ap-gto%40yahoogroups.com>
, "ceheber" <cheber@...> wrote:
>
> Richard,
>
> I think you hit it on the head. After using a blow drier off
and on
> this morning, it seems to be working fine again. I think I'll
start
> storing it indoors from now on. I've been keeping my setup
outside
> under one of the TeleGizmo 365 covers - I read recently where
those
> covers are great at storing condensation - that might be the
issue.
>
> Chuck
>
>
> --- In ap-gto@...
<mailto:ap-gto%40yahoogroups.com> , "Richard Moore" <moorerh2@> wrote:
> >
> > Chuck,
> >
> > I had the same problem, random uncontrolled slews,
> > after my CP3 servo and/or its connectors got wet.
> > After drying everything out with a hair dryer everything
> > went back to normal for about an hour. So I gave up
> > and sent the CP3 and the Y cable back to AP. Wally
> > could not find anything wrong and sent it back to me.
> > It now works perfectly. My guess is that by the time
> > it got back to AP that everything had thoroughly
> > dried out. I now tape a piece of plastic sheeting over
> > the CP3 to prevent excessive dew or an
> > unexpected rain shower from getting it wet.
> >
> > I also invested in a spare Y cable, spare power cable
> > and a spare CP3 servo. Since I travel to a dark site and
> > stay for 3 to 6 nights, it is worth the extra money to
> > ensure that I do not have to cut my photon collection
> > time short.
> >
> > Richard
> >
> >
> >
> > ----- Original Message -----
> > From: ceheber
> > To: ap-gto@... <mailto:ap-gto%40yahoogroups.com>

> > Sent: 11/25/2007 12:57:28
> > Subject: [ap-gto] Fried Mount
> >
> >
> > I've had a 900GTO for nearly two years. It has performed
flawlessly
> > and brilliantly for the entire time. Until this weekend. On
start
> > up, after keying in the location, the mount runs away in
Dec. I can
> > get it to stop by fiddling with the Dec movement keys on the
keypad
> > but then, when I try to resume from park, it's off again.
> > Occasionally on start-up, I get an error message on the
keypad saying
> > "Motor Stall". Occasionally, I can get thing to partially
behave and
> > when I try to move the mount in RA, it behaves as if it is
possessed,
> > moving randomly. I assume, since both the Dec and RA motors
move that
> > the problem is in the controller. Any way I can definitively
diagnose
> > this? Any suggestions on what is going on? Help!
> >
> > Chuck
> >
> >
> >
> >
> >
> >
>


Re: DOVELM2 and Mach1

Howard Hedlund
 

Hello Pierre,



The DOVELM2 can be used on the Mach1GTO without any additional adapter,
even when using the center knob position. The knob is not quite as
convenient in that position, but it does clear the hub of the dec axis
and is quite functional. Likewise, the DOVELM16S does not require any
adapter for use with the Mach1GTO. We don't recommend using the
DOVELM16 because the larger knobs have some clearance issues.



Mag. 7 skies!



Howard Hedlund

Astro-Physics, Inc.

815-282-1513

________________________________

From: ap-gto@... [mailto:ap-gto@...] On Behalf
Of phenrotay
Sent: Wednesday, November 21, 2007 12:33 PM
To: ap-gto@...
Subject: [ap-gto] Re: DOVELM2 and Mach1



I hae no feedback yet for the DOVELM2 but have now the same question
for the DOVELM16/DOVELM16S as well: is an adapter required (such as for
the DOVE08) to raise the dovetail on a Mach1 ?

Pierre
--- In ap-gto@... <mailto:ap-gto%40yahoogroups.com> ,
"phenrotay" <Pierre.Henrotay@...> wrote:

Dear,

the DOVELM2 allows both the DUP and DUPS plates to be used: a central
hole is present on the knobs side for the smaller plates (DUPS).
Question: can the DOVELM2 be used on a Mach1 in this configuration
(ie
using the middle hole) ? Or is an adpter required (such as for the
DOVE08) to raise the dovetail ?

Best regards,
Pierre


Re: Fried Mount

ceheber
 

...then again, maybe not. Turned the mount back on after blow drying
it and it behaved normally - but, after an hour or so, the mount
started to chatter then run away in RA, it stopped and I got the
"motor stall" message (and power light turns yellow). Doesn't seem to
be the Y-cable. Both RA and DEC are moving when it behaves. I've
checked the voltage coming from the power supply and it is dead on
(13.8vdc). Any other suggestions greatly appreciated.

Chuck

--- In ap-gto@..., "ceheber" <cheber@...> wrote:

Richard,

I think you hit it on the head. After using a blow drier off and on
this morning, it seems to be working fine again. I think I'll start
storing it indoors from now on. I've been keeping my setup outside
under one of the TeleGizmo 365 covers - I read recently where those
covers are great at storing condensation - that might be the issue.

Chuck


--- In ap-gto@..., "Richard Moore" <moorerh2@> wrote:

Chuck,

I had the same problem, random uncontrolled slews,
after my CP3 servo and/or its connectors got wet.
After drying everything out with a hair dryer everything
went back to normal for about an hour. So I gave up
and sent the CP3 and the Y cable back to AP. Wally
could not find anything wrong and sent it back to me.
It now works perfectly. My guess is that by the time
it got back to AP that everything had thoroughly
dried out. I now tape a piece of plastic sheeting over
the CP3 to prevent excessive dew or an
unexpected rain shower from getting it wet.

I also invested in a spare Y cable, spare power cable
and a spare CP3 servo. Since I travel to a dark site and
stay for 3 to 6 nights, it is worth the extra money to
ensure that I do not have to cut my photon collection
time short.

Richard



----- Original Message -----
From: ceheber
To: ap-gto@...
Sent: 11/25/2007 12:57:28
Subject: [ap-gto] Fried Mount


I've had a 900GTO for nearly two years. It has performed flawlessly
and brilliantly for the entire time. Until this weekend. On start
up, after keying in the location, the mount runs away in Dec. I can
get it to stop by fiddling with the Dec movement keys on the keypad
but then, when I try to resume from park, it's off again.
Occasionally on start-up, I get an error message on the keypad saying
"Motor Stall". Occasionally, I can get thing to partially behave and
when I try to move the mount in RA, it behaves as if it is possessed,
moving randomly. I assume, since both the Dec and RA motors move that
the problem is in the controller. Any way I can definitively diagnose
this? Any suggestions on what is going on? Help!

Chuck






Re: Fried Mount

Richard Seavey
 

Rolando
I think what Anthony (and I) would find useful is a wiring diagram of the Y
cable showing the numbered connector pins. This would make it easy to do
simple Ohm meter continuity and short tests.

Richard

At 01:45 PM 11/26/2007 -0500, you wrote:

In a message dated 11/26/2007 12:27:27 PM Central Standard Time,
<mailto:ayiomami%40otenet.gr>ayiomami@... writes:

Examine all wire connections on your Y cable to see where the break
is. When
you find the break, resolder the wire on the pin and your mount
should work
fine. If you cannot find a break in the wire, we can run some more
tests to

Can I trouble you for some further information here in relation to
these tests for our information and future reference should something
similar happen?
By swapping Ra and Dec motors, you can determine if the problem is in the Y
cable or in the motor itself. This is the first test that I would do if
one of
the motors behaves erratically.

Rolando

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Re: Awesome Mount

Roland Christen
 

In a message dated 11/26/2007 5:28:46 PM Central Standard Time,
kattnerk@... writes:


Well just so you know,

I took my AP900 out to the Texas Hill Country over Thanksgiving, got
it set up with my c9.25, camera, rotator, aol unit, and filter wheel
(lots of weight). I decided to see how well that mount tracks, so I
ran PEMPRO while I cooked some good german sausage on the grill. And
guess what? +/- 1 arcsec without PEC. I didn't believe it and ran
it two more times and made sure I was looking at the correct axis.
Still +/- 1 arcsec. Although the moon was almost full, it was a
magical night imaging M1 with an AWESOME mount.

Thanks AP.
Hey, sounds great! Wally does a nice job assembling each mount and testing
the gears for accuracy. He rejects gears that don't meet spec and makes sure
that everything is copecetic before bundling them up. Then we keep our fingers
crossed that the UPS is kind and gentle to the packages.

Rolandio


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Re: Fried Mount

ayiomamitis
 

--- In ap-gto@..., chris1011@... wrote:

Examine all wire connections on your Y cable to see where the break
is. When
you find the break, resolder the wire on the pin and your mount
should work
fine. If you cannot find a break in the wire, we can run some more
tests to

Can I trouble you for some further information here in relation to
these tests for our information and future reference should something
similar happen?

Anthony.

determine if the motor encoder is faulty or if the servo is faulty
(both have very
low probability - broken wire in the Y cable has highest probability).

Rolando


Re: Unexpected slews - AP1200GTO

ayiomamitis
 

Chris1011@... wrote:
In a message dated 11/23/2007 11:47:36 AM Central Standard Time, ayiomami@... writes:


As a result, the only unknown in all of this is the quality of my
Y-cable. One of the reasons (amongst others) I wanted the Mach1GTO is
that I would have a backup system in the event anything went wrong
with my AP1200GTO. I now see that the Y-cable is a potential problem
(incompatibility) and, as a result, I will look into getting a
second/backup cable for both the 1200 and Mach1
Rolando,

The reason your RA motor will slew uncontrollably is probably because the servo is not getting a signal from the motor encoder. What happens is this: the servo sends a voltage to the RA motor to get it turning at the sidereal rate and expects to get a number of pulses back from the encoder because the shaft is turning. If the servo does not get a return signal, it sends more voltage to the motor (this happens very quickly). This is a normal action of a feedback loop, and will result in the motor getting the full dc bus voltage applied across the terminals, which in turn causes a rapid slewing. Still no signal from the encoder, so the servo will shut down after a 2 second time period built into the software, and a signal is sent to the keypad that the motor has stalled.

The servo has this built-in 2 second until shut down because in some cases the motor is actually stalled, and we do not want to send full voltage indefinitely to the motor windings. If the motor is not turning due to jammed gears, the windings will melt in due time when 12 volts is applied with no rotation.
Thanks for the explanation since I was curious as to why the attempted slew at start-up and before any initialization by me using the keypad (location etc).

Therefore the most likely explanation in your case is that a wire has come off the connector on your Y cable. It could be on the RA motor side or on the servo side. Open up the connector and look at the pins to see where the wire has broken off.
I will open up the connector and take a peek!

Anthony.

Rolando


Re: Fried Mount

ceheber
 

Richard,

I think you hit it on the head. After using a blow drier off and on
this morning, it seems to be working fine again. I think I'll start
storing it indoors from now on. I've been keeping my setup outside
under one of the TeleGizmo 365 covers - I read recently where those
covers are great at storing condensation - that might be the issue.

Chuck

--- In ap-gto@..., "Richard Moore" <moorerh2@...> wrote:

Chuck,

I had the same problem, random uncontrolled slews,
after my CP3 servo and/or its connectors got wet.
After drying everything out with a hair dryer everything
went back to normal for about an hour. So I gave up
and sent the CP3 and the Y cable back to AP. Wally
could not find anything wrong and sent it back to me.
It now works perfectly. My guess is that by the time
it got back to AP that everything had thoroughly
dried out. I now tape a piece of plastic sheeting over
the CP3 to prevent excessive dew or an
unexpected rain shower from getting it wet.

I also invested in a spare Y cable, spare power cable
and a spare CP3 servo. Since I travel to a dark site and
stay for 3 to 6 nights, it is worth the extra money to
ensure that I do not have to cut my photon collection
time short.

Richard



----- Original Message -----
From: ceheber
To: ap-gto@...
Sent: 11/25/2007 12:57:28
Subject: [ap-gto] Fried Mount


I've had a 900GTO for nearly two years. It has performed flawlessly
and brilliantly for the entire time. Until this weekend. On start
up, after keying in the location, the mount runs away in Dec. I can
get it to stop by fiddling with the Dec movement keys on the keypad
but then, when I try to resume from park, it's off again.
Occasionally on start-up, I get an error message on the keypad saying
"Motor Stall". Occasionally, I can get thing to partially behave and
when I try to move the mount in RA, it behaves as if it is possessed,
moving randomly. I assume, since both the Dec and RA motors move that
the problem is in the controller. Any way I can definitively diagnose
this? Any suggestions on what is going on? Help!

Chuck




[Non-text portions of this message have been removed]


Re: Fried Mount

Roland Christen
 

In a message dated 11/26/2007 4:15:56 PM Central Standard Time,
jlc@... writes:


("Fried mount" is ~probably~ not quite the appropriate topic name, but does
get our attention.)
Right, and it gives aid and comfort to competitors who must be chuckling over
the dozens and dozens of posts with this heading. You know, sometimes a quick
e-mail to the AP guys like Howard (copy to me) can solve many problems much
faster than wading through the numerous theories that come up on newsgroups.
Then, when everything is fixed and working right, you can post a results on the
newsgroup to alert others as to potential problem, the symptoms, how to fix
it, etc.

Rolando


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Re: Fried Mount

Roland Christen
 

In a message dated 11/26/2007 2:39:13 PM Central Standard Time,
cheber@... writes:


Roland,

Comment on the y-cable came from the fact that, initially, both axes
were behaving strangely. Right now, I've got things running smoothly
again on both axes. I've jiggled the cables while everything is
running with no impact. I will check the connections on the pins to
be sure that the cable is or isn't the issue.
From your initial discription one axis ran away, The Dec I believe. Then the
servo quit after 2 seconds. You may not have had the cables fully seated, or
there is a break in the connections which is intermittent. When a servo motor
runs away for a short time, 2 seconds, and then quits, it is an indication that
the servo is not getting an encoder signal, and that possibly there is a
connection problem in the cable.

Even though the cables have strain reliefs, after a period of twisting the
wires, perhaps tugging on them, it is possible for the connection to eventually
fail. Therefore I urge everyone to check their cables once in a while,
especially if they are plugged and unplugged numerous times. In real humid
environments the pins could conceivably become oxidized, so check the conditions of the
pins also.

Rolando


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Re: Unexpected slews - AP1200GTO

ayiomamitis
 

Hi Bob,

I am in the fortunate position in having a brand new Mach1GTO waiting
for action (soon) and which allowed me to test various components
common with the AP1200GTO so as to systematically remove possible
culprits.

With anaxiety await news from Howard and/or Rolando. Given the size of
the threads over the past four days in relation to these slews, they
will need half a day to read all of the messages. :-)

Anyway, my bets are on my Y-cable being the source of my problems.
Let's see.

Anthony.

--- In ap-gto@..., "astronomertoo" <bobc22@...> wrote:

Hi Anthony, all,
We have similar frustrations, but likely different answers. First it
is very important to have a real power supply (like the AC power
supply AP offers) or a well maintained battery that will have low
enough source impedance and ampere hour capability to drive the
system at high speed, which requires several amps, NOT milliamps,
AND not drop under 12 VDC. I use a full size 105 AH Stowaway in a
battery case for long star parties and never run low of power.
I have a similar run-away drive problem, which I have been fighting
with for 5 years on my AP900. I have spoken to Howard about it, who
offered to check it out but I would have to lose it for a while, and
for reasons like Mars, or Jupiter or new comets, I have not sent it
in yet. Someday I will have to. But it can work fine for a while,
then one night out of the blue it will take off repeatedly and has
driven my scope into the pier several times (!!) shrieking at 1200x
rate. Only then do I ever get an overload light, for very good
reason. I have frantically started unscrewing the lock ring on the
power cord plug on more than a few nights when the stop button would
not stop it, and live in fear of that dreaded sound. It does make
for a bad night. The standard recommendations are to spread the
loose power plug split pin wider for better contact, and checking
the power and Y cable for open circuits. I have no power supply
problem and I am sure the cables and connectors are good. I have
learned to not bother recalibrating the system again after 3
failures in any one night. I could send it in for service or just
use it to track. I often just use it to track and move it by hand,
or use the key pad for motions and options, but do not push GO-TO
for fear of another runaway, which is especially freaky if I hit the
stop key. Only recently I have been getting the message of "object
below horizon", so now Go-To does not work anyway. I recently
learned here that I can fix that if I change the memory battery and
learn how to download a program into the control box.
I will be looking to see what you learn.
Fair skies,
Bob Cuberly

--- In ap-gto@..., "ayiomamitis" <ayiomami@> wrote:
The most puzzling part of all is that everything was working
fine the
other day for the first 30-45 minutes when I started my usual
routine
of cooling the CCD camera, finetuning focus, centering my
target
properly etc ... a few minutes before my intended start time
(19:00)
the problems started (while connected and everything humming
along).
Anthony,
Hi Bill,
In my mind you have not actually verified the power source ?.
Until that
I have tried three sources of power ... my original battery with
which the problems started, the new battery purchased today as well
as one of those portable 17Ah batteries which I was using originally
with my AP1200GTO. In fact, for the latter, I tried three such 17Ah
batteries which I now use for my Kendrick dew system.
is done you might be chasing rainbows. Certainly you must have
available
a 110 <=>13.8 VDC power supply to run some tests with ? Even a 3
amp

I have a transformer for 230v to 3/4.5/6/7.5/9/12v but I have no
means
to test the proper polarity (I am electronically illiterate). It
also
supplies 300mA which I recall being too low on the basis of a
previous
message to Rolando.

supply is enough to isolate the problem. It is not enough
current to
actually use though. Batteries are notorious at not producing
enough
voltage and or current. Roland has suggested that this should be
verified *first*. And past threads have confirmed this wisdom.
The only piece of the puzzle which I cannot confirm one way or
another
is my Y-cable. Now, if this was also ruled out as a potential
trouble
spot, I would be out of options.

Then again if you have done this and I missed that then I
apologize.
But
every one of these symptoms sounds like a power problem.
Please do not apologize. I am so frustrated and desperate that ANY
suggestion and thought is most welcome.

I must wait till Monday to see what Rolando and Howard can suggest.

Anthony.


Re: Fried Mount

Roland Christen
 

In a message dated 11/26/2007 1:43:12 PM Central Standard Time,
cheber@... writes:


...then again, maybe not. Turned the mount back on after blow drying
it and it behaved normally - but, after an hour or so, the mount
started to chatter then run away in RA, it stopped and I got the
"motor stall" message (and power light turns yellow). Doesn't seem to
be the Y-cable.
Why would you say that it does not seem to be the Y cable? Have you actually
checked the connections on the pins? If the motor encoder signals do not get
to the servo, it will slew uncontrollably for 2 seconds and shut down with
Motor Stall message on the keypad and light turning yellow. All this is explained
in the manual in great detail. Check the pins to see where the break in the
cable might be. Somewhere along the line the servo is not getting the signal
from the motor encoder. Fiddling with the cable wires might get you a temporary
connection, and make it seem like the problem is fixed. Check the cable
connections - the wires on the pins (remove the connector covers to expose the pins).

Roland Christen


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Re: Fried Mount

Roland Christen
 

In a message dated 11/26/2007 12:27:27 PM Central Standard Time,
ayiomami@... writes:


Examine all wire connections on your Y cable to see where the break
is. When
you find the break, resolder the wire on the pin and your mount
should work
fine. If you cannot find a break in the wire, we can run some more
tests to

Can I trouble you for some further information here in relation to
these tests for our information and future reference should something
similar happen?
By swapping Ra and Dec motors, you can determine if the problem is in the Y
cable or in the motor itself. This is the first test that I would do if one of
the motors behaves erratically.

Rolando


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Re: Fried Mount

Roland Christen
 

In a message dated 11/25/2007 2:57:50 PM Central Standard Time,
cheber@... writes:


I've had a 900GTO for nearly two years. It has performed flawlessly
and brilliantly for the entire time. Until this weekend. On start
up, after keying in the location, the mount runs away in Dec. I can
get it to stop by fiddling with the Dec movement keys on the keypad
but then, when I try to resume from park, it's off again.
Occasionally on start-up, I get an error message on the keypad saying
"Motor Stall". Occasionally, I can get thing to partially behave and
when I try to move the mount in RA, it behaves as if it is possessed,
moving randomly. I assume, since both the Dec and RA motors move that
the problem is in the controller. Any way I can definitively diagnose
this? Any suggestions on what is going on? Help!
Usually, a motor will run wild because it is in an uncontrolled loop. The
servo sends a voltage to the motor to start it rotating, and the shaft encoder on
the back of the motor sends back a series of pulses to tell the servo that
the motor is rotating. If the pulses are missing (bad connection on the Y cable
connectors), then the servo sends more voltage until the motor is running flat
out. With still no signal coming out of the encoder, the servo software
determines that there is a problem, and shuts down all motion - after 2 seconds. It
also sends a signal to the keypad that the motor has stalled.

Examine all wire connections on your Y cable to see where the break is. When
you find the break, resolder the wire on the pin and your mount should work
fine. If you cannot find a break in the wire, we can run some more tests to
determine if the motor encoder is faulty or if the servo is faulty (both have very
low probability - broken wire in the Y cable has highest probability).

Rolando


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Re: Unexpected slews - AP1200GTO

Roland Christen
 

In a message dated 11/23/2007 11:47:36 AM Central Standard Time,
ayiomami@... writes:


As a result, the only unknown in all of this is the quality of my
Y-cable. One of the reasons (amongst others) I wanted the Mach1GTO is
that I would have a backup system in the event anything went wrong
with my AP1200GTO. I now see that the Y-cable is a potential problem
(incompatibility) and, as a result, I will look into getting a
second/backup cable for both the 1200 and Mach1
The reason your RA motor will slew uncontrollably is probably because the
servo is not getting a signal from the motor encoder. What happens is this: the
servo sends a voltage to the RA motor to get it turning at the sidereal rate
and expects to get a number of pulses back from the encoder because the shaft is
turning. If the servo does not get a return signal, it sends more voltage to
the motor (this happens very quickly). This is a normal action of a feedback
loop, and will result in the motor getting the full dc bus voltage applied
across the terminals, which in turn causes a rapid slewing. Still no signal from
the encoder, so the servo will shut down after a 2 second time period built
into the software, and a signal is sent to the keypad that the motor has stalled.


The servo has this built-in 2 second until shut down because in some cases
the motor is actually stalled, and we do not want to send full voltage
indefinitely to the motor windings. If the motor is not turning due to jammed gears,
the windings will melt in due time when 12 volts is applied with no rotation.

Therefore the most likely explanation in your case is that a wire has come
off the connector on your Y cable. It could be on the RA motor side or on the
servo side. Open up the connector and look at the pins to see where the wire has
broken off.

Rolando


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Re: Unexpected slews - AP1200GTO

Roland Christen
 

In a message dated 11/23/2007 2:11:49 AM Central Standard Time,
ayiomami@... writes:


Thanks for the feedback! To answer your two questions, yes, I do have
an intermediate cable between the cigarette lighter plug on the AP
power cable and the battery
keep the power cord as short as possible because a long wire will cause
significant voltage drop unless it is made of heavy guage wire.

Roland


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Re: Unexpected slews - AP1200GTO

Roland Christen
 

In a message dated 11/23/2007 2:11:49 AM Central Standard Time,
ayiomami@... writes:


I could not find a deep-cycle marine gel battery yesterday and had to
resort to doing an internet search at home last night which yielded me
some hits of stores to visit today and which carry them.
Gel cells do not last very long. A battery used for trolling motors on small
fishing boats is best.

Rolando


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Re: 3600GTO - El Capitan unveiled at AIC

Roland Christen
 

In a message dated 11/23/2007 12:09:09 AM Central Standard Time,
rickwiggins@... writes:


Hi Roland,
I expect that if you are operating your mount manually or through a
simple planetary program, you may not ever have the mount get lost.
However; if you operate remotely in an automated environment, you are
going to have the mount get lost. There are so many indeterminate
failure modes of all the software and the computers, that it is very
likely that you will have this happen. It has happened twice to me.
Once when a Windows error caused a freeze and then reboot during the
night. A second time was when an error between two programs stopped a
CCDCommander action and the mount eventually hit the pier. Both
instances caused the mount to hit the pier, clutches to slip, and
mount to get lost.
Thanks, Rick
The problem is this: Once the mount is lost, which way should the axes move
in order to find the homing signal? east or west?

For a mount which cannot track through the meridian, this question is simple.
For a mount that we make with clutches and the ability to track through the
meridian, this is not so simple.

By the way, the 3600 can be permanently locked down in one position if need
be. The clutches will not slip. Another option will be for the astrographic
configuration where your scope cannot hit the pier and can swing freely through
360 degrees in RA.

Finally, although your command programs might mess up and your computer might
fail, the servo always knows where it is. therefore, a simple RA/Dec command
to the servo will result in proper positioning, regardless of failures in the
commanding software. Only a failure in the servo electronics or an improper
Sync will cause the mount to become inoperable.

Hitting the pier in a non-astrographic setup is still a possibility. This can
be eliminated by the use of two switches added to the RA and Dec axis which
define the maximum limits that the scope can track or slew to, and turn off the
power to the servo if these limits are reached. A remote switch added across
the contacts of this power switch can re-activate the servo to allow you to
slew the mount back into safe territory.

Rolando


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Re: Unexpected slews - AP1200GTO

astronomertoo
 

Hi Anthony, all,
We have similar frustrations, but likely different answers. First it
is very important to have a real power supply (like the AC power
supply AP offers) or a well maintained battery that will have low
enough source impedance and ampere hour capability to drive the
system at high speed, which requires several amps, NOT milliamps,
AND not drop under 12 VDC. I use a full size 105 AH Stowaway in a
battery case for long star parties and never run low of power.
I have a similar run-away drive problem, which I have been fighting
with for 5 years on my AP900. I have spoken to Howard about it, who
offered to check it out but I would have to lose it for a while, and
for reasons like Mars, or Jupiter or new comets, I have not sent it
in yet. Someday I will have to. But it can work fine for a while,
then one night out of the blue it will take off repeatedly and has
driven my scope into the pier several times (!!) shrieking at 1200x
rate. Only then do I ever get an overload light, for very good
reason. I have frantically started unscrewing the lock ring on the
power cord plug on more than a few nights when the stop button would
not stop it, and live in fear of that dreaded sound. It does make
for a bad night. The standard recommendations are to spread the
loose power plug split pin wider for better contact, and checking
the power and Y cable for open circuits. I have no power supply
problem and I am sure the cables and connectors are good. I have
learned to not bother recalibrating the system again after 3
failures in any one night. I could send it in for service or just
use it to track. I often just use it to track and move it by hand,
or use the key pad for motions and options, but do not push GO-TO
for fear of another runaway, which is especially freaky if I hit the
stop key. Only recently I have been getting the message of "object
below horizon", so now Go-To does not work anyway. I recently
learned here that I can fix that if I change the memory battery and
learn how to download a program into the control box.
I will be looking to see what you learn.
Fair skies,
Bob Cuberly

--- In ap-gto@..., "ayiomamitis" <ayiomami@...> wrote:
The most puzzling part of all is that everything was working
fine the
other day for the first 30-45 minutes when I started my usual
routine
of cooling the CCD camera, finetuning focus, centering my
target
properly etc ... a few minutes before my intended start time
(19:00)
the problems started (while connected and everything humming
along).
Anthony,
Hi Bill,
In my mind you have not actually verified the power source ?.
Until that
I have tried three sources of power ... my original battery with
which the problems started, the new battery purchased today as well
as one of those portable 17Ah batteries which I was using originally
with my AP1200GTO. In fact, for the latter, I tried three such 17Ah
batteries which I now use for my Kendrick dew system.
is done you might be chasing rainbows. Certainly you must have
available
a 110 <=>13.8 VDC power supply to run some tests with ? Even a 3
amp

I have a transformer for 230v to 3/4.5/6/7.5/9/12v but I have no
means
to test the proper polarity (I am electronically illiterate). It
also
supplies 300mA which I recall being too low on the basis of a
previous
message to Rolando.

supply is enough to isolate the problem. It is not enough
current to
actually use though. Batteries are notorious at not producing
enough
voltage and or current. Roland has suggested that this should be
verified *first*. And past threads have confirmed this wisdom.
The only piece of the puzzle which I cannot confirm one way or
another
is my Y-cable. Now, if this was also ruled out as a potential
trouble
spot, I would be out of options.

Then again if you have done this and I missed that then I
apologize.
But
every one of these symptoms sounds like a power problem.
Please do not apologize. I am so frustrated and desperate that ANY
suggestion and thought is most welcome.

I must wait till Monday to see what Rolando and Howard can suggest.

Anthony.


Re: Fried Mount

Richard Moore
 

Chuck,

I had the same problem, random uncontrolled slews,
after my CP3 servo and/or its connectors got wet.
After drying everything out with a hair dryer everything
went back to normal for about an hour. So I gave up
and sent the CP3 and the Y cable back to AP. Wally
could not find anything wrong and sent it back to me.
It now works perfectly. My guess is that by the time
it got back to AP that everything had thoroughly
dried out. I now tape a piece of plastic sheeting over
the CP3 to prevent excessive dew or an
unexpected rain shower from getting it wet.

I also invested in a spare Y cable, spare power cable
and a spare CP3 servo. Since I travel to a dark site and
stay for 3 to 6 nights, it is worth the extra money to
ensure that I do not have to cut my photon collection
time short.

Richard

----- Original Message -----
From: ceheber
To: ap-gto@...
Sent: 11/25/2007 12:57:28
Subject: [ap-gto] Fried Mount


I've had a 900GTO for nearly two years. It has performed flawlessly
and brilliantly for the entire time. Until this weekend. On start
up, after keying in the location, the mount runs away in Dec. I can
get it to stop by fiddling with the Dec movement keys on the keypad
but then, when I try to resume from park, it's off again.
Occasionally on start-up, I get an error message on the keypad saying
"Motor Stall". Occasionally, I can get thing to partially behave and
when I try to move the mount in RA, it behaves as if it is possessed,
moving randomly. I assume, since both the Dec and RA motors move that
the problem is in the controller. Any way I can definitively diagnose
this? Any suggestions on what is going on? Help!

Chuck