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Subject: [M]: Magellan II Equipped LX 50 Experience
From: TheRone@aol.com
Reply To: mapug@shore.net
Date: Tue Dec 31 00:34:12 1996

After finally receiving a Magellan II for my new 10 inch LX50, I eagerly
began the installation.

I was surprised to find out I had to replace a computer chip on the power
panel of my LX50 due to the fact that my new scopes software was apparantly
already obsolete and incompatable with the Magellan II.

After the chip was replaced I began the encoder installations. The DEC
encoder was installed easily but when I went to install the RA encoder I
discovered that the mounting screw holes that were supposed to be located in
the drive base were not. Upon calling Meade, I was instructed to go ahead
and drill and tap the holes myself. They also mentioned that if I screwed
this up, they would cover it. I gladly did it myself rather than ship the
scope back and it worked out fine.

One thing that bothered me about the RA encoder installation was the fact
that the cable was too short to rest flat against the fork assembly. It had
to be stretched accross the fork at a 45 degree angle near the base in order
to be plugged in. Although the scope cleared the cable when swinging
through, this really annoyed me.

When the big moment came to try it out, I was disappointed. I found that no
matter how accurately I polar aligned the scope and how carefully I centered
on alignment stars (and I tried for days since I am new at all of this),
objects were seldom found in the field of view of my 18mm Super Wide
eyepiece. In fact, I was sometimes off more than 2 degrees.

After some investigation, I found that my DEC encoder was inconsistent. I
would center an object, note the encoder count, move north then back to to
the object, then south and back to the object and found I could be off by 8
or 9 encoder counts. Upon calling Meade again, they agreed to swap both
encoder assemblys for new ones. I received them and installed them. This
time the RA encoder cable was long enough to rest nice and flat against the
fork assembly.

Since I was eager to check out the new installation but the sky was cloudy, I
began comparing the DEC encoder counts to the scopes setting circles. Noting
that there were suppose to be 4096 counts for a complete revolution and the
gear ratio was 1:1, I did the following. I positioned the scope at +90
degrees DEC then turned on the scope. When checking the encoders through the
Magellan, I found that it would initialize the count at either zero, -1, or
+1. I would then move the scope to 0 degrees DEC and expect to find an
encoder count equal to -1024 plus whatever it was at initialization. I
repeated this at 90 degree intervals and was surprised to discover that I
could be off by as much as 9 counts. But each time I did this, I was pretty
dead on 4096 counts for a complete revolution. Suspecting that maybe the
encoder assembly gears were not perfectly round or not centered on the axis
of rotation, I called Meade again.

After consulting with their engineers, the fellow at Meade called me back and
said that during testing of the LX50's they had the same problem and it was
caused by the gear and spacer on the DEC knob stud not being centered on its
axis. He then asked me if I had wrapped tape around the DEC knob stud before
I slipped the spacer/ring gear assembly onto it as was recommended in the
instructions. I did not since I thought the fit was snug enough but I was
apparantly badly mistaken. He suggested that I carefully wrap tape around
the stud four times and try it again.

Even after careful taping , I was off by about 4 counts. After playing with
the DEC assembly for hours I learned how incredibly sensitive it is to the
slightest variations in many variables. By changing the position of the DEC
ring gear ralative to the scope and the DEC ring gear relative to the encoder
gear, I was able to affect the counting accuracy. I gave up after I was able
to get an accuracy of 1 count off at 0 degrees, 2 counts off at -90 and 1 off
at -180 when starting at +90 degrees.

I have not yet been able to test out the new assembly due to weather. Should
I be satisfied with the accuracy of the encoder assembly I was able to
obtain? Has anyone else had similair problems? Any suggestions?

Also I have been recording a number of little "quirks" I have experienced
while using the Magellan II. I mentioned a few of them while talking to
Meade. The fellow I talked to didn't seem too concerned and recommended that
I solve the encoder problems first then contact them if I continued to have
other problems. That was fine with me since it has a one year warranty so I
have plenty of time to check it out. I did see a past posting that mentioned
a flash upgrade to a version 1.3 that solved some type of problem. Since I
have version 1.2, could someone enlightnen me as to what those problems were
that prompted Meade to send the upgrade? Apparantly I didn't say the magic
words because it was never mentioned in my discussions with Meade.

Thanks,

Tom