Last updated: 30 April 2007

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This page is for user comments and information of a general nature or items applicable to all LXD55 and LXD75 models. If you have any comments, suggestions, questions or answers to questions posed here, e-mail them to me and I'll post them. Please use an appropriate Subject Line on your message. Thanks.

Subject:	RA gear movement on LXD55
Sent:	Sunday, April 29, 2007 13:54:55
From:	Lamar McLouth (lmclouth@a1isp.net)
I don't know if this exact issue has been discussed before, if so,
please point me in the right direction.

I've had my LXD55 SC-8 since 2003 and over the past year or so I've
noticed I get quite a lot of movement after I release the left arrow
button on the Autostar.  This issue does NOT occur with any of the other
directions; not even the other RA button (i.e. right.) It's not what I
understand "backlash" to be because it's not just the re-meshing of the
gear teeth.  In fact, I'm not sure exactly what it is!

If I press the left button for say 5 seconds (with speed set to 5), the
RA motor gold gear will turn counterclockwise while I'm holding the
button.  When I release the button, the gear will turn back the opposite
way (clockwise) for another 3 or 4 seconds.

Do you have any idea what is causing this? Could it be one of the
settings in the Autostar that needs to be changed?  (I do have the
latest Autostar software installed.)

This is really an annoying problem because I have to overshoot my
subject by quite a distance and then release the button and have it pull
it back in.

Thanks for your help.

Mike here: After you updated to the latest AutoStar version did you do a TRAIN DRIVES? I always recommend doing that. If that doesn't help, doing a CALIBRATE MOTORS and TRAIN DRIVES may eliminate the problem.
Subject:	RE: Hey Mike...LXD75
Sent:	Thursday, April 19, 2007 07:47:15
From:	Stephen Olson (stephen99@comcast.net)
I got my shed. Im pretty excited. Just curious if you know how to
determine the height of the pier? Can I just use the mount and tripod
and guesstimate it? Any suggestions? I posted a few questions on yahoo
and nothing too good for replies. Thanks again.

Mike here: There are several factors to consider. What is the minimum and maximum height where you want the eyepiece to be? Same applies to the finderscope and any accessories you attach (camera, imager, guidescope, Barlow Lens, Off-Axis Guider, etc.). You also need to consider the "free area" for the counterweight to avoid obstructions. How short or tall will the observers be? Do you need to use a ladder for viewing? What about a chair for those long observing or guiding sessions? And lastly, there is the shed itself. Don't forget the shed wall height; how high does the telescope need to be to see objects low in the sky? And there is probably some maximum height due to the shed roof. I'd recommend setting up the tripod and giving all these considerations a run through. Adjust the tripod height as necessary until you are comfortable that you have the GEM head height where it meets most of your requirements. That should give you a good idea how to set up the pier.


Mike here again: You might want to check out the Ash Observatory construction page (just posted to the ETX Site Astronomy Links page):
Subject:	Hey Mike...LXD75
Sent:	Tuesday, April 17, 2007 11:53:56
From:	Stephen Olson (stephen99@comcast.net)
Hope all is well in your world. My wife finally "let" me get a shed for
my scope. It defiantely cost me, but I got it. Wanted your thoughts on
the pier and size. I was thinking about using concrete. 8" diameter?

Also what about a plate for the LXD75? Do i need to but something to
mount to the concrete? Got a link? IF concrete isnt really needed what
about 4x4 in wood? Your thoughts? As usual..thanks for your help. Its
greatly appreciated! If you dont mind I just set up a new website for my
telescope and stuff. Was hoping to link your site there. Do you mind?
its not completed, but should be done by next week.
Mike here: I haven't investigated piers (yet) but there are several companies that advertise them in the back of Sky and Telescope magazine. You might want to discuss your needs with one of them. Alternatively, there are some pier concepts on the Helpful Information: Telescope Tech Tips page. Most of these are for the ETX telescopes but it may give you some ideas.
Subject:	Fried cicuit board followup
Sent:	Sunday, April 8, 2007 16:34:26
From:	Steve (bullfox@comcast.net)
After a few phone calls, Meade is sending me a new declination motor
assembly.  In the meantime, I installed the declination motor assembly
from the LXD55 on the LXD75 and found that it works perfectly.  I am
about 100% convinced that the problem was a small screw or metal shaving
that fell across the board and shorted it out.
From:	richard seymour (rseymour@wolfenet.com)
In the past, Meade has been very good about doing warranty
work on scope which have had intelligent attempts at
repair or "tune up".

Your burned circuit card -could- have been caused by
a motor fault (shorted coils, broken commutator)
so sending in "only the cards" may not fix the root problem.
The fact it "runs fine" (without carefully monitoring
the current/voltage draw during bidirectional operation)
is only a clue, not an affirmation, of "happy motor".

good luck


From the looks of the burn mark, I am almost 100% sure something bridged
a couple of the components on the circuit board.  In no attempt to be
humorous let me say that sometimes the nose is a useful diagnostic tool.
 When I "sniff" the motor it smells like it should, i.e. slight smell of
oiled metal,  no burned smell,  and no burn marks, but the board is
visibly and odoriferously burned.

The new declination motor just arrived.

Subject:	re: PEC training messing up tracking rate on LXD-75
Sent:	Sunday, April 1, 2007 17:54:54
From:	richard seymour (rseymour@wolfenet.com)
Andrew Johansen is working on a new version of his PEC Editor
to try and help address this issue.  If Meade can't/won't,
we'll try (even if they can)

have fun

Subject:	blown circuit board in LXD75
Sent:	Saturday, March 31, 2007 22:32:41
From:	Steve (bullfox@comcast.net)
Finally got the new LXD75 out under the stars on a clear night.  It
worked perfectly for about 1 minute.  I did a one star alignment and it
hit Sirius almost dead on.  Then I asked it to slew down to M41.  It was
just bringing the cluster into the eyepiece when the declination motor
reversed direction for about 10 digress then jittered to a stop and
begin emitting a strong odor of burned insulation.  I could find no
evidence of any jamming in the gears.

I removed the declination motor housing from the mount, and removed the
motor from its housing.  The motor circuit board has a significant flash
burn on the side of the white plastic plug that brings the wiring into
the board, and two of what I believe to be diodes next to the white plug
are fried.

Autostar seems to be ok, but it does not give me a motor fault error. 
The RA motor slews but wont track, even after a reset.  I am hoping it
wont track because of the problem with the burned board.  I unplugged
the declination motor from the circuit board and tested it with 12v dc. 
It runs fine...

I suspect that the circuit boards are the same in the LXD55 and 75, so I
am thinking of installing the old board from my LXD55 into the 75.

Any thoughts or suggestions you may have would be appreciated.
Mike here: Odd. And unfortunate. Since the LXD75 is new it is still under warranty. I would suggest pursuing that before replacing the board, which might invalidate the warranty. As to whether the LXD55 board would work, it seems like it should but don't recall any reports of that being done.


I probably already invalidated the warranty by opening it up and
regressing everything..  I was just going to send the circuit board back
to Meade and ask them to replace it free, and either use the other dec
motor assembly or the other board in the meantime.  Have you heard of
any other similar problems?.
Mike here: I have my doubts that they will just send a circuit board. They will likely want the whole GEM head back. Haven't heard of any fried LXD boards. Have heard of fried ETX boards however. There can many many causes.

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