Date
1 - 12 of 12
GTO Keypad Freezes Problem
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Terry Johnson <tjohnson@...>
Marj, I spoke with Roland about a problem I was having with my
600GTO mount. The problem centers around the GTO keypad. I have explained the
problem below in more detail. Would you please see that he gets this
information. I will also provide a printed copy when I send you the equipment he
requested.
The Problem
I was just completing a polar alignment process using the
north polar alignment procedure, I was using Polaris and Vega as my two stars,
as I was doing a final alignment on Vega, and was asked to press 'menu' to have
the scope slew to polaris for the final time, I pressed the 'menu' key on
the keypad and nothing happened. I pressed the key several more times and still
nothing happened. I pressed other keys and still nothing happened. The keypad
was locked on the 'press menu to exit' command.
I was able to get around the problem by turning off and on the
power to the GTO control box. I now had to polar align again.
Since I was very near completing the alignment in the previous
aligning process, it did not take long to polar align this time. After aligning,
I slewed the scope to Vega. I then added the additional equipment for
taking exposures(see Equipment, after polar aligning, below). I was going to
slew to another location in the sky, however, the keypad was lock up again
while on Vega. The problem was the same where the keypad was locked on the
'press menu to exit' key.
I gave up for this evening, packed up and went
home.
The next night I was able to polar align correctly. I then
added my guiding equipment for camera exposures (see Equipment after polar
alignment, below) I slewed to arcturus to practice my guiding on a bright star.
After having success on the guiding practice, I decided to take an exposure of
M-13. I keyed in M-13 using the keypad, pressed the 'GOTO' key
and the scope did not move, however, the keypad did display the information
about M-13 as it normally does after you press the 'GOTO' key. I pressed other
keys and still no response. I had to power off/on the GTO control box to clear
the problem.
Possible Causes
I would appreciate any advice or experience on what is causing
this problem. Roland has asked that I send in my keypad, cables, and GTO
control box to be checked out. I will send the equipment in
tomorrow.
Thanks for your help in this matter...Terry
Johnson
The Equipment:
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rck <rkuberek@...>
Hi Terry,
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Something like this has happened to me several times. I narrowed it
Regards,
Terry Johnson wrote: Marj, I spoke with Roland about a problem I was having with my 600GTO mount. The problem centers around the GTO keypad. I have explained the problem below in more detail. Would you please see that he gets this information. I will also provide a printed copy when I send you the equipment he requested. |
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Terry Johnson <tjohnson@...>
Bob, when you speak of undervoltage, when do you consider the
voltage to be too low. My 88 amp battery with all the systems
connected puts out 12.8 volts when the battery is fully charged to
12.2 volts after six hours of usage.
Terry
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rck <rkuberek@...>
You have tested it at 12.8 volts or that is what it is rated to produce?
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I was getting under 12 volts when I had the problem. After I switched
Regards,
Terry Johnson wrote: Bob, when you speak of undervoltage, when do you consider the voltage to be too low. My 88 amp battery with all the systems connected puts out 12.8 volts when the battery is fully charged to 12.2 volts after six hours of usage. |
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Terry Johnson <tjohnson@...>
Bob, I have a voltage meter attached to the battery that
displays the battery voltage. Do you know whether a short drop in voltage caused
by connecting an additional CCD camera and PC would to the battery would
cause the keypad to lock-up if the keypad was already attached to teh
battery?
Thanks...Terry Johnson
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toddg18522@...
In a message dated 6/15/00 10:51:24 PM EST, rkuberek@... writes:
<< Hi Terry, Something like this has happened to me several times. I narrowed it down to undervoltage, and since fixing that, it's ok. >> I had similar problems when undervoltaged |
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toddg18522@...
In a message dated 6/15/00 11:14:46 PM EST, rkuberek@... writes:
<< You have tested it at 12.8 volts or that is what it is rated to produce? I was getting under 12 volts when I had the problem. After I switched to a marine deep cycle 60AH battery, no problems--I can run for 2-3 nights on one charge. Just the scope though, nothing else on it. >> try a battery that delivers 13-14v for awhile... I ran into problems under 12v I think |
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rck <rkuberek@...>
Terry,
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Yes, I suspect that it would, but I don't know for sure. Regards,
Terry Johnson wrote: Bob, I have a voltage meter attached to the battery that displays the battery voltage. Do you know whether a short drop in voltage caused by connecting an additional CCD camera and PC would to the battery would cause the keypad to lock-up if the keypad was already attached to teh battery? Thanks...Terry Johnson |
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Terry,
>>I have a voltage meter
attached to the battery that displays the battery voltage. Do you know whether a
short drop in voltage caused by connecting an additional CCD camera and PC would
to the battery would cause the keypad to lock-up if the keypad was already
attached to teh battery?<<
Roland
said that this is likely to happen. Your meter is reading an average and will
not show dips. Gel cells have internal resistance which will cause voltage drop
when the load changes. When you connect an additional CCD camera and PC the load
will drop below 9 volts and the keypad will reset or it may affect the GTO
circuit itself and cause the keypad to lock up.
We
recommend that you use a large marine battery that is not a gel cell and hook
everything up to it before powering up the GTO.
Hope this helps. Thank you for providing me with another issue
to address in the troubleshooting section of the manual.
Marj,
Astro-Physics
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Chris Spratt
I use the Kendrick 17amp 12-volt battery recommended by Astro-Physics
to power their scopes. It is just adequate for my AP600E GOTO. Even though it shows 12.9 volts on the voltmeter prior to being used this may not be enough to power the scope. My solution (apart from getting a larger battery)is to charge it after every observing session. My CCD (Pixcel 237) is powered by another Kendrick 17amp 12-volt battery. Here to the CCD won't work unless the battery has been charged right prior to each observing session. Even if the battery shows 12.8+ volts the CCD may not work properly. It is best to charge after each session even if you have a larger battery. I feel that the the Kendrick 17amp batteries are really too small for running a GOTO mount (or even a CCD). As for running both the mount and CCD off one battery - a huge one is required here! --- In ap-gto@..., "Marj" <marj@a...> wrote: Terry,batteryI have a voltage meter attached to the battery that displays the voltage. Do you know whether a short drop in voltage caused byconnecting an additional CCD camera and PC would to the battery would cause thekeypad to lock-up if the keypad was already attached to teh battery?<<average and will not show dips. Gel cells have internal resistance whichwill cause voltage drop when the load changes. When you connect an additionalCCD camera and PC the load will drop below 9 volts and the keypad willreset or it may affect the GTO circuit itself and cause the keypad to lockup. cell and hook everything up to it before powering up the GTO.address in the troubleshooting section of the manual.displays the battery voltage. Do you know whether a short drop in voltage causedby connecting an additional CCD camera and PC would to the batterywould cause the keypad to lock-up if the keypad was already attached to tehbattery? rated to produce?for 2-3 nights on one charge. Just the scope though, nothing elseon it. consider the voltage to be too low. My 88 amp battery with all the systemsconnected puts out 12.8 volts when the battery is fully charged to 12.2 voltsafter six hours of usage.---------------------------------------------------------------------- -- ---------------------------------------------------------------------- -- ---------------------------------------------------------------------- ------ ---------------------------------------------------------------------- ------ |
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Terry Johnson <tjohnson@...>
Chris, I believe my keypad locking problem was probably caused by a dip in
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voltage after I powered on my ST-4 and 12V to 110V inverter that I use to power my PC. I watched the volt meter when I powered up the 12V inverter/PC and saw the battery voltage go from 13.2V to 12.6 and then settle in at 12.8. I have a feeling the GTO control box is very sensitive to power drops and therefore causes the keypad to lock. I now plug all of my components into the 12V 88 Amp battery first. I then connect the 600GTO control box as the last unit, whichs seems to have taken care of the problem. Just another learning curve. ...Terry Johnson ----- Original Message -----
From: "Chris Spratt" <cspratt@...> To: <ap-gto@...> Sent: Saturday, June 17, 2000 6:51 PM Subject: [ap-gto] Re: GTO Keypad Freezes Problem I use the Kendrick 17amp 12-volt battery recommended by Astro-Physics |
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Lawrence D. Lopez <lopez@...>
Firstly a large deep discharge battery is the
way to go. Sam's sells deep discharge/cranking batties (which weigh 50 #) and I have used them for all sorts of things. Powering a home made inverter, a trolling motor, a tractor and finally a AP400 mount. Of course this only works if you are a weight lifter. Size matters. Secondly a spike current on any battery is going to drop the voltage. There are three ways to get around that: 1. isolate by using a separate battery (already mentioned). 2. Use a 12 volt DC to 120 volt AC converter. I believe that the current crop of inverters has a DC to DC converter followed by a DC to AC converter. I suspect that the DC to DC converter regulated the voltage. With or without a 120 volt to 12 volt DC switching converter (the type that radio shack sells). While somewhat less efficient you should have very regulated voltage using this. You should be isolated from any transient battery effects. Of course the 12 to 120 volt inverters typically drop out at 10 volts. 3. An isolation diode and a big capacitor or small battery. The big capacitor might be one of those things they use for car audio systems so that the load from the audio system doesn't reset the car computer. |
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