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Last updated: 31 July 2013

This page is for comments and user feedback about ETX telescopes. ETX models discussed on this page include the ETX-60/70/80/90/105/125 (EC, AT, BB, Premier Edition). This page also includes comments and feedback of a general nature. Comments on accessories and feedback items appropriate to the ETX-90RA, DSX, and DS models are posted on other pages. If you have any comments, suggestions, questions or answers to questions posed here, e-mail them to me for posting. Please use an appropriate Subject Line on your message per the Site Email Etiquette. Thanks. Remember, tips described on this site may invalidate the warranty on your telescope or accessories. Neither the submitter nor myself are responsible for any damage caused by using any contributed tips.

Subject:	Meade 35-4702-00 electronic controller wiring diagram
Sent:	Tuesday, July 30, 2013 06:01:44
From:	Alex Card (
I wonder if any kind soul can help me. I'm a total noob where telescopes
are concerned but recently bought an ETX90 which has a dead Electronic
Controller model number 35-4702-00.

There is no activity from it so I unscrewed the back and found that 7 of
the 8 wires were detached from the PCB.

The Orange wire is still connected to the 2nd point from the left but
I'm wondering if anyone can advise me which points the other colours
should be soldered to please ?
Many thanks,
Alex Card

Subject:	Eyepiece holder
Sent:	Tuesday, July 23, 2013 17:06:05
From:	Gregory J. Scotti (
I wonder if you might know the thread size and length of the eyepiece
holder on an ETX 80? I lent my telescope to a friend, and got it back
minus the eyepiece holder. Unfortunately I didn't check the scope right
away and Meade tells me this piece is part of the telescope and NOT
available as a separate part. My friend has offered to pay for the
holder, but it looks like I'll have to have it made. Any help you can
provide would be greatly appreciated.

Gregory Scotti
Sent from my iPhone
Mike here: If you mean the screw, see "Q. What is the size of the eyepiece holder screw?" on the ETX FAQ page.


Actually, the entire eyepiece holder tube that screws into the telescope
is what I'm missing. It's the tube that the eyepiece drops into. I was
hoping maybe someone would have the dimensions of this tube so I could
have one made, as Meade doesn't offer this for sale and weren't very
helpful about giving me the dimensions.
Again thanks,
Greg Scotti
Mike here: Egads. I don't know the dimensions of the ETX-80 holder but you might try Telescope Warehouse (link on the Astronomy Links page) for a replacement.

Subject:	Re: Wide angle 30mm+ eyepiece
Sent:	Monday, July 22, 2013 07:25:16
From:	Chris Mcilhargey (
Ok thanks a lot!

So in your opinion would a 32mm be too much?

Sent from my iPhone
Mike here: I have found my 40mm useful when wanting wide-field, low magnification views. A 32mm eyepiece can be useful; just understand its limitations.


Ok thanks I am after a nice wide view. I think I will try find a Meade
4000 32mm giving around 60x mag.

Thank you very much for all your help btw! I really do appreciate it!

I got the etx flashed to 43eg and connected and controlled thru
stellarium on my MacBook. I just bought a modded web cam so I can see
what I'm looking at on the laptop too! Very excited :)



Subject:	Wide angle 30mm+ eyepiece
Sent:	Sunday, July 21, 2013 04:23:05
From:	Chris Mcilhargey (
I'm sorry to bother you again but I was wondering if you could maybe
give me some advice.

I really want a wide angle 30mm or more eyepiece. Due to the etx 125
long focal length even my 26mm is still quite high magnification.

I had a look in the eyepiece section here on your site but most are very

Was just wondering if you could suggest a good one?

I'm not looking to spend a fortune! Max maybe like 70 ($100).



Sent from my iPhone
MIke here: I've used a 40mm eyepiece on my ETX telescopes. I also use a wide-field adapter on my ETX telescopes. There is one issue with either: the central obstruction becomes more evident. Long focal length eyepieces will allow you to see the central obstruction. Depending on the particulars of the eyepiece, it can be more or less evident.

Subject:	mended
Sent:	Thursday, July 18, 2013 13:17:38
From: (
Just had the guy that I work with around, to have a look at the scope.
He turned the lower part of the up/down mechanism around 90 degrees, so
the worn teeth were at the back, put it all back together, problem
It still makes the odd click, but it's almost back to as new.
Just had it tracking Arcturus, even though it's light and cloudy, but
Stellarium never lies.
It's a shame there isn't a cut off point when things get too low or too high.
Thought I'd tell you my good news.
All the best, George 

Subject:	Etx 125 turning left is very loud
Sent:	Thursday, July 18, 2013 08:07:08
From:	Chris Mcilhargey (
First off can I just say your site is amazing!! Thanks so much for it! I
have spent many hours reading all I can about the etx here :)

Sorry if its mentioned somewhere however I couldn't seem to find the
info I'm looking for (prob cause I have no idea about the terminology
used for the mounts and gears etc)

basically my new (used) etx125 makes a considerably louder noise when
moving left! All other directions seem fine! Only left is very loud. Is
there anything I can do that is basic enough for me to do without
damaging stuff to try and fix it?

Or any explanation on why it does this?

Much appreciated!

Mike here: There are a couple of possibilities but before getting into those, be certain you have done a CALIBRATE MOTOR and TRAIN DRIVES (on both axes). If that doesn't solve it, the gear motor mount could be loose (or broken). With the azimuth (RA) axis unlocked, do you hear the same loud noise when slewing left? Does the slew speed matter? With the axis unlocked, if you slowly move the telescope to the left by hand, do you feel any resistance difference vs turning it to the right? If so, there could be some obstruction.


Wow that was a fast response!! :)

I can confirm that I have done both of them. Thanks to your site for
explaining how to do it :)

How often do I need to train the drives? Every time I use the scope? I'm
sure I read it's only every few months or something.

I will try and see if there feels like any interference when moving
manually tonight after work. However I'm pretty sure there isn't.

From memory the slew speed does decrease the noise however all
directions are quieter and going left is still louder than another

It's not a big deal to be honest as it still moves and from what I can
tell it tracks fine. I just thought it sounded a bit dodgy. And wanted
the opinion of the etx god!! :)

Thanks again! I will update you when I have checked your suggestions.



Sent from my iPhone
Mike here: TRAIN DRIVES usually doesn't need to be done very often. CALIBRATE MOTOR should be done when replacing the ETX batteries or switching power sources. It should also be done if battery power is getting low and no replacement batteries are available. TRAIN DRIVES should be done after doing an AutoStar ROM update (but version 4.3Eg is the latest, best version for the older AutoStar #497). It should also be done following a RESET. Otherwise, do it if you see "rubberbanding" or other GOTO/tracking oddities.


Ok thanks very much! I have got into a habit of doing a calibrate motors
each time I use the scope as it only takes seconds. I always use the 12v
into a plug socket so nothing to do with batteries.

Ohh on that point about autostar update. It's an old version off the top
of my head 39 something. I have ordered what I hope is a working USB to
serial adapter to update it (first one I bought was junk)

It's unlikely but would the old version of autostar have anything to do
with the loud noise nah?

Btw totally off topic but... I love this scope! It's truly amazing.
Thanks to your site it gave me the confidence I  needed to part with my
money! (Third scope in 6 months of this hobby)

i managed to push the magnification up to 475x on the moon the other
night and it focused fine!! :)

Also got my first view of a DSO M13 and almost shat myself when I found
it!! :) 
Mike here: Yes, the ETX is a "mighty" telescope! The older version is not likely to be the culprit. As to the USB adapter, not all work reliably with the AutoStar. If you find that the AutoStar Update application from Meade doesn't stay connected, try StarPatch from StarGPS ( or AutoStarX if you use a Mac (


Thanks for that! i will use the link for updating with a Mac. i did hear
tho that autostar suite cant be used on a mac :(

Ok so i tried to see if there was any difference when moving manually. I
couldnt notice anything. it moved left and right with no problems. Do
you think it would be worth opening and having a look inside? i dont
want to break anything.
Mike here: Opening up and looking is probably a good idea.


sorry for bothering you mate!

I have one question about the autostar update. i downloaded autostarx to
update using my macbook. i then cleared eeprom. But i dont have the
latest version of autostar. Where can i download it? i tried the meade
site but it only gives .exe for windows files.
Sorry if this is a stupid question :)


Mike here: See the AutoStar Software Archive on the Helpful Information: AutoStar Info page. You want the ROM file 4.3Eg.

And this:

Love the speed of your responses btw!!

Thanks for that. Another stupid question... Do I pick the latest one
yeh? I.e. "landmark path kit for autostar v43eg (v30)" or is that just a
addon to "patch kit for v43eg" dated 2007?

Mike here: Start with no patches. The patch software is Windows only. And just to clarify, use the 4.3Eg ROM file from the AutoStar Software Archive page.


Ahhh ok I found it now! Thanks so much! I should have followed your
instructions better the first time!

It's flashing 43eg now :)

Btw just in case it may help someone not make the mistake i did when
attempting to connect the etx to a mac...and buy a cheap USB adapter.

The second one I bought seems amazing with both windows 8 and osx 10.2.8
just download driver and plug it in. no messing about with com ports or
nothing. For only 10. Gets great reviews too.

Thanks again for the help!!

Now I will attempt to open this beast and try and work out what's making
this noise in the mount :)

Subject:	Re: ETX 90 Tracking Problems
Sent:	Wednesday, July 17, 2013 07:42:32
From:	Micki Goodman (
Thanks for your typically quick reply. I should have told you I do not
have Autostar. It is the simpler, multi-button ETX 90EC hand controller.
I hope you, or anyone else has seen this problem before, and found a
solution. Thanks again.
Mike here: You previously said "If I try to adjust the tracking speed for the left side of the FOV then the tracking is off on the opposite side (opposite drift)." How are you adjusting the tracking speed?


The hand controller has tracking speed adjustments, via the focus in/out
arrow buttons, when you enter the appropriate "Mode".
It allows incremental speed changes for slower and faster. I typically
try to get the best tracking in the middle of the FOV, but it is more
accurate, initially, to the right side of the FOV. I have had little or
no problems setting the Polar alignment, thanks to your previous info.
Once I get this tracking issue solved, I will be able to do longer video
clips. Thanks again for all your help.
Mike here: It has been years since I've used the EC Handcontroller. I thought the only speed adjustments were slewing. There are four slewing speeds available with the EC Handcontroller.


All true, Mike, of slewing. So-what do you recommend (who might know) as
to the tracking issue?
Thanks again.
Mike here: If tracking is inconsistent, the RA gear could be loose on its shaft. Or the motor is going bad. You could contact Dr Clay Sherrod for his Supercharge tune-up service. Or get an AutoStar #497, which provides tracking speed adjustments.


Thanks for the suggestions. I will check the RA gear first, then decide
from there which steps to take. As I mentioned, the hand controller I
have has tracking speed adjustments and they work quite well.
I look forward to more of your Cassiopeia postings, when your wether clears.
Mike here: You are correct. I checked an ETX EC manual and Appendix A described the key presses to change tracking from 0.5% of sidereal rate to 65%, either faster or slower. Getting to 65% requires 127 key presses. I had forgotten about this adjustment capability. Of course, this only applies with the telescope mounted in Polar mode, either with the short tripod legs (optional with the ETX-90EC) or on a tripod that can be adjusted for your latitude. If you still see some drifting after making the adjustments, it could be that the your mount is not precisely polar aligned. Using Magnetic North may not be accurate enough if your local Magnetic Variation is large. But sighting on Polaris should be accurate enough for short durations. For more accurate polar aligning, use the "Drift Method" (see the "Polar Alignment Guides" section on the Helpful Information: Guides & References page.


I spent some time today and tonight checking focus shift and later
tracking issues. During the day I took off the electric focuser and
there was negligible focus shit, manually. I lubricated the electric
focuser brass gear and the circular brass gear, that came with the
electric focuser mounted on the focus shaft), and it made the shift more

The tracking problem persists and I will look at the RA gears soon (I
did a complete overhaul, lube etc. not too long ago).

It was too gusty for photography and even viewing was turbulent, but the
observing was still enjoyable of the Moon and Saturn.

As a side note, I made some stands, to attach tarps to, to help block
neighborhood light pollution, and from passing cars lights.

It will be helpful, when the wind is not so strong. The last post you
had of your neighbors' lights, to your north, seemed more considerate. I
hope that continues, when the weather affords more sessions.

Yours-Fred (you may sometimes see my wife's name instead of mine since
we only have one joint email account).

Mike here: Universe Today published an article by David Dickinson on "How to Spot and Track Satellites". One of my ISS-Moon transit photos was used in the article. Check it out.

Subject:	screws?
Sent:	Tuesday, July 16, 2013 10:40:03
From: (
The screws on the Meade are a different kind, as you know.
Any chance of you telling me what does fit the screws?
The guy I work with is a whizz with electrical stuff, and is pretty good
with his hands.
I'm going to get him to come have a look at it, and would like to know
what kind of screw driver to take with him.
It might, hopefully, be an easy fix, even though I doubt it myself. I'm
hoping it's just something jumped out of line.
Regards, George
Mike here: Many screw heads are "hexagonal cross-section" and need a "hex key" (also known as an "Allen wrench"). They may be SAE or Metric sizes.


Thanks Mike

Subject:	Spares?
Sent:	Tuesday, July 16, 2013 07:55:34
From: (
Do you happen to know where I could find a vertical cog for my ETX?
I was trying out the goto the other night, went to answer the phone. The
next I knew it was ripping the cog apart.
Having looked all over the net, and with Meade saying they don't do the
ETX any more, I'm stumped where to find a new or second hand cog.
Would the cog out of my ETX 80 fit the 125AT?
Thanks in advance, George
Mike here: I suggest trying Telescope Warehouse (link on the Astronomy Links page). Also, there are some gear source and replacement articles on the Helpful Information: Telescope Tech Tips page. As to the ETX-80, doubtful.

Subject:	ETX90EC skewing problem
Sent:	Monday, July 15, 2013 08:56:04
From:	Tom S (
Using the controller, skewing at low speed is perfect in all four
directions.  Motor operation and gear box sounds are normal.  However in
the next three higher speeds the motor seems to bog down (like not
getting the correct voltage) and the gear train will not rotate. Removed
the bottom cover for a visual inspection of wiring and components and
all looks very satisfactory.  Suspect a faulty PCB.  Is there another
item I should be concerned with? and am I on the right track?
Thanks, Tom 
Mike here: I assume from your description that you have only the standard EC handcontroller and not the AutoStar. Could you be overtightening the axis locks. Is the slewing (not "skewing") problem only on one axis or both?


Thanks for your fast reply.  Yes on the standard EC handcontroller and
not autostar.  Tried different tension on the axis locks, no help. No
slewing on either axis.
I never use higher speeds at all, maybe I need to be satisfied with what
I have (the one low speed) but wanted to have the scope perfect.
Mike here: Have you replaced the ETX batteries with fresh ones? Be certain they are all inserted correctly.


Batteries new, also used a power supply to make higher speeds.
Mike here: With both axes unlocked, can you hear both motors running at the higher speeds? Also, what's the voltage and amperage supplied by the external power supply?

Subject:	clean gear plastic ETX 70
Sent:	Monday, July 15, 2013 01:09:49
From:	toni toni (
Hello, my name is Antonio.
I have a Meade ETX-70.
I'll clean plastic gears has the mount.
My question is: I read that lithium grease is not suitable to be plastic gears.
What type of grease is recommended?.
Thank you very much for your attencion.
Mike here: See the current Live Forum feedback; I provided an answer on grease last night.

Subject:	re: ETX90 Motor Drive
Sent:	Saturday, July 13, 2013 19:33:28
From:	richard seymour (
Assuming you mean an ETX90 with Autostar,
fascinating (to some of us) detail can be gleaned from Meade's patents.

I normally use

and give it these numbers:
6,304,376  6,392,799  6,445,498   6,563,636  align: 6,922,283
there's also
7339731, 7221527, 7092156, 7079317, 7053992, 7414707, 7227223

In short, the motors are all DC analog motors with 150 Hz PWM drive pulses.
There's a local processor on each motor card which does the "tight
servo" loop processing to keep the motor moving at a speed commanded by
the master CPU in the Autostar.

have fun

Subject:	ETX90 Motor Drive
Sent:	Tuesday, July 9, 2013 14:21:58
From:	JimD (
Just recived the Meade ETX90 scope, & am in the process of checking it
out.  Do to the less then average sky conditions, & bumper crop of bugs,
astronomical views have been pretty poor. However the terrestial views,
are equal to the 3.5" Questar, which I have used on & off over the past
4 decades.

Star tracking, has been good, considering I have it on a wooden deck in
the back yard, & have not done a true polar alignment.

Having been involved with the design of optical instruments, I was
wondering if you have any informatioin as to the drive systems of the
ETX, for my own curiosity? i.e. prints or equivalent that show the
detail drive operation. The ones I have been most familiar have a dual
servo & sync. A.C. motor (RA only).
Thank you, JimD.
Mike here: You didn't specify whether you have the ETX-90RA (original ETX without the handcontroller), ETX-90EC/AT (with EC or AutoStar handcontroller), or an ETX-90PE (AutoStar; LNT). But all the information that I have is available on the Helpful Information: Telescope Tech Tips page and the Helpful Information: AutoStar Info page.

Subject:	Re: Dusting off old scope, Stuck "finding level"
Sent:	Tuesday, July 9, 2013 08:41:36
From: (
When I get back from Yosemite I'll take on the project of building a
cable and doing the update to see if that resolves these issues.  If
not, I'll reach out to Dr. Sherrod.

Thank you again for all your efforts.


From:	Ron (
I had some problems with my LNT module and found I had a broken wire in
the harness/wires  that runs from the LNT connector to the DEC Motor
card in the right fork.  If one of the wires that is in the AUX circuit
is broken causing intermittent operations Eric may get the Red Dot but
still not be able to get the full auto alignment.  Just guessing her but
as the ETX rotates a broken wire may break the circuit causing
everything to stop. I forget what my symptoms were but at the time I was
able to buy a LNT module from Meade before I discovered the broken wire.
 The ETX OTA and forks pretty much has to be disassembled to be able to
test the wires for continuity.  Plugs are on both ends.

I will try to find the file with the part numbers for the connector and
pins and forward it.  They are MOLEX parts and available from several
sources.  Only the pins would be needed.


And more:

Attached are the MOLEX Documents for the connector housings and pins, male and female.

Plug Housing 1

Plug Housing 2

Plug Housing 3

Plug Terminals

One thing to note is that there are different part numbers for single pins and tapes of pins.


Subject:	about your FaceBook
Sent:	Tuesday, July 9, 2013 00:47:47
From:	T.Yashiro (
You taught many about ETX to me.
I am very thankful to you. If I can,I would like to visit your FaceBook.
I found your twitter.
But I could not find your FaceBook.
Please tell me where your FaceBook is.
I am glad if I can be your friend by FaceBook. Regards,
Takashi Yashiro
Mike here: I am not on Facebook. There are too many security issues with Facebook.

Subject:	Help please, with RA problem
Sent:	Monday, July 8, 2013 15:27:25
Just purchased a ETX 105, of  course i did all the things one shouldn't
do when purchasing from a stranger. I didn't check to see if it was
functional. Well, Fortunately , Cosmetically it is near perfect, and I
did pay 350.00 for it, which . I think is pretty good. Only one problem.
The RA doesn't work it just makes noise. I tried a setup first, and once
it started, Dec worked fine, but when it should have shifted left or
right, it just didn't move, there was noise, but no movement.

I can't get any help from Meade support of course, and I can't afford
the cost from the few people that fix this sort of thing. Most fixes
would probably cost more than what I paid for it.

An hour later, frustrated, I went back to the scope, and by tilting the
scope to the left while it was still on the tripod, the RA did work ,
but only while I held the arrow key down, once I stopped, it would not
work again, unless I tilted it again. It also would only move counter
clockwise. Clock wise only produced noise. Like fast clunking?

I've tried all speeds, and all produce the same effect, nothing but

I do not want to hurt the scope so I wont use it till I fix it...but how

Does anyone know a fix for this, and does it sound serious?

Thank you for taking the time to read this.


Michael Rollo
Mike here: With the axis UNLOCKED, do you hear the same noise? When locking the axis for normal operation, be certain to not over tighten it. It should be just tight enough that the telescope will not easily move if you push it by hand. If the lock lever seems to not tighten enough, there is an easy fix for that. Also, assuming no other problems, be certain you have done a CALIBRATE MOTOR and TRAIN DRIVES (on both axes).


Thank you,

It sounds the same locked or unlocked.

There is no problem with the locking mechanism, it wont reach midway
befor it it gets hard to push any further..which,..I'm afraid I
I have noticed at slow slewing speeds that even when it wont actually
move to the left, I can see it in the eyepiece that it is trying to grab
at something.

The sound is like a power drill. and when I try to slew to the will make a clunking sound.

I am thinking of opening it up. I have been assured by the previous
owner that it hasn't been used more than a half dozen times..i tend to
believe her. As it looks untouched.

Last it was touched was 6 years she says.

I can't imagine what could make this happen.

Thanks again, if you can think of anything else that it may be, please
feel free to let me in on is greatly appreciated.
Mike here: Since the sound is the same when unlocked, it could be that a motor or gear has become loose. You will have to open the base and look around. You may see a loose motor or gear mount or perhaps even a broken mount. There are some repair tips for that on the Helpful Information: Telescope Tech Tips page.

Subject:	Dusting off old scope, Stuck "finding level"
Sent:	Sunday, July 7, 2013 23:16:48
From:	Eric Rosenzweig (
I have an ETX-105PE running version 43Ea that hasn't been used in a
couple of years and I've decided to get it going again.  It worked when
I put it away a couple of years ago (scope wrapped in original plastic
bag and placed in locking case).  So, I replaced the ENT battery as the
old one was dead and have been trying to get it to work ever since
(checked the new battery and voltage is fine).  Here's what I've done
and the results:

1.       Started by trying an auto align and it gets stuck at "finding
level".  Can sit there for over 15 minutes before I give up and turn it
off/on or the Autostar just goes black.
2.       Tried a two star align using Deneb as the first star.  Scope
pointed 180 degrees from Deneb
3.       When I try an auto align it comes up and prompts for time.  The
date is correct, but the time is always 8pm.  I found an email on your
site referring to make sure the red-dot finder works and it does.
4.       Tried calibrate sensors.  Gets past "finding level" slews
"finding North" (actually end up pointing West) and gets stuck at
"releveling".  Let it stay for 15 minutes before reboot.
a.       Tried it again and it never got past "finding level"
5.       Did a "Reset", went through setup process and all of the above
still happening. Oddly after the reset it was as if it didn't see the
LNT as I didn't get the usual prompts for auto align.  However, after I
turned it off and back on, it appeared normal although still wouldn't
get past 'finding level'.

I've searched your site and the internet and haven't found anything
along these lines other than checking the connection between the LNT and
the scope which I did and it's fine.

I'm heading to Yosemite next week and was hoping to get this scope
going.  Obviously I can use the scope without these features, but was
hoping for more.
Any help you can provide would be greatly appreciated.
Mike here: First, the AutoStar will always show 8pm (or 2000) as the default time on power on. Second, you might want to update to 4.3Eg (the last, best, version for the old #497 AutoStar). If replacing the battery in the LNT didn't help (still locking up finding level), then it could be that the LNT has failed. If that's the case, you should still be able to use the non-Auto alignment modes. So, lets start by getting that to work. You said (#2) that Two Star Align was not working properly. Have you done a CALIBRATE MOTOR (different than CALIBRATE SENSOR) and a TRAIN DRIVES afer you did the RESET? If not, do those. Also be certain you have fresh batteries in the ETX (and not just the LNT). Next, remember (in case you forgot after a couple of years on non-use) that the HOME position for Auto and non-Auto alignment modes are different. Be certain to use the correct one.


Thanks for getting back to me so quickly.  Couple of questions before
this evening:

1.      I can't find an option for CALIBRATE SENSOR.  I had found that
note on your site, but can't find that option.  Even in the manual for
scope where it shows all the Autostar menu options there's not one for
CALIBRATE SENSOR.  Is this hidden somewhere?

2.      I thought I had read on your site that if the LNT was working
correctly it would keep the time, but if that's not the case that's
fine.  FYI, I did notice that there were a couple of times where I
checked the time and it was about 30 minutes fast.

Thank you again.
Mike here: If there is no CALIBRATE SENSOR option, then the AutoStar is not "seeing" the LNT module. The LNT will get the time IF you have the optional Atomic Clock module connected.


I'll play with it more tonight but I thought
if I could turn on the red dot finder, which I can, the LNT was talking
to the scope?

One other thing that happened once,  which may confirm the lack of
connectivity, is that after the reset when I went to CALIBRATE MOTOR the
scope slewed a bit up and over while saying TESTING MOTOR. after I
turned it off and on that didn't happen. I just got stuck on FINDING

Other than the physical connector from the LNT is there anything else I
can check?

Thanks again.
Mike here: Does the Finder options appear in the MODE menu display? If not, then there is some problem with connectivity. But that could be a separate issue from the leveling sensor problem. As to CALIBRATE MOTOR, yes, it briefly runs the motors to check operation and measure the power output of the batteries via the optical encoders.


Well, I'm at wits end.  I forgot that I had a new LNT from when I first
got my scope and the red dot didn't work right so OPT got me a new one
on warranty and then was able to get the other one working.  Long story
short I have two.  So I've done the following with the following

1.      Put new battery in new LNT (call it nLNT).  Got calibrate
sensors as an option, kicked it off and it worked great. Leveled,
rotated to find North and then got stuck at releveling.  Joy followed by

2.      Put in old LNT (call it oLNT).  Got calibrate sensors as an
option as well. Definitely wasn't there before.  Tried it and it got
stuck at leveling.

3.      Put in nLNT.  Tried to calibrate sensors, got stuck at leveling.

4.      With both oLNT and nLNT calibrate motors works fine.

5.      With oLNT tried 2 star alignment (thanks for the reminder that
the home position is different) and it got in the ballpark, but not
really close.  When I finished with two stars it told me alignment

a.      I couldn't remember how to set time with DST so I tried it with
DST off, and when it was 9:30 local time I set it to 9:30 with DST ON
and 8:30 with DST ON thinking that might help, but didn't get me much
closer to the alignment stars.  For the record if it's 9:30pm here in
California where we're in DST, how should I set the clock?

6.      Had the same oddity with the time slipping 30 minutes forward
with oLNT.

7.      Also on more than one occasion after turning off/on when it came
to date the month field was wacky.  As I scrolled through I got
gibberish, REV and then finally the months.

I've repeated this a couple of times and never get past leveling.  With
both LNTs I get the red dot finder options and they seem to work fine. 
I don't have an RS232 port on my computer so I would need to get a USB
to RS232 cable to update the Autostar, but I don't have time for that
before I leave.

So, I'm at an impasse and it would appear there's a serious problem
somewhere so, given that the scope is certainly out of warranty, is
there anyplace better to send it for a tuneup other than Meade?

Thanks again for all your help and your responsiveness.  Much
Mike here: First on DST: when your location is using Daylight Saving Time (as California is now), DST should be set ON. When you "fall back" later this year, set it OFF. For locations that don't do the clock dance (like here in Arizona), DST should always be OFF. I'm beginning to think the AutoStar is at fault since both LNT modules experience the same problem. As a next step, I suggest updating it to 4.3Eg. Use either the Meade AutoStar Update application version 4.6 (both the ROM file and application are available on the AutoStar Software Archive (on the Helpful Information: AutoStar Info page). You can also use StarPatch (from You will need a #505 serial cable (easily made; see the AutoStar Info page). If your computer has only USB, you will need a USB-serial adapter. Not all adapters work reliably with the AutoStar; I recommend Keyspan adapters. If you have another adapter, use StarPatch as it is more forgiving of USB-serial adapter issues. If you do want to send it to someone for repair, I suggest contacting Dr. Clay Sherrod for his Supercharge Tune-up Service (see the link on the ETX Site home page).

Subject:	ETX-125 DEC Slip
Sent:	Sunday, July 7, 2013 13:13:24
From:	John Deriso (
After a total overhaul of the mount (bearing changes, motor swaps, etc.)
then RESET/CAL/TRAIN, my go-to's are fine in any AZ or DEC direction,
but then I get a slow downward drift of the OTA. No AZ drift.  Is there
anything else but DEC clutch slip that can cause this in astronomical
target mode? I haven't fooled with DEC ratio or percentage.  Didn't try
terrestrial mode yet to confirm it's not tracking error.  Trying to
avoid tearing completely back down to reach the DEC clutch surfacesthe
one thing I didn't inspect.  I'm quite familiar with ETX 70/90/125
repair and the torque normally needed for DEC lock.
Mike here: Just to confirm, did you TRAIN DRIVES on both axes? If so, it could be slippage. Is the drift downward the same regardless of OTA orientation? That is, is it the same if pointed southward as when pointed eastward? Is it the same if mounted Alt/AZ vs Polar?


Yes, trained both drives, still downward drift after go-to in any
direction.  No AZ drift. I never mount polar.  I'm guessing that
checking for DEC drift in terrestrial mode (motors not running) will
confirm it's not tracking error, but clutch slippage.  I was curious if
DEC drift like this could be firmware related or if it really is likely
mechanical slippage.  Shame on me for not inspecting the DEC clutch for
grease or wear when I installed this replacement base/forks onto an
existing OTA.  Considerable cannibalization to get one ETX-125 from 2
hulks, but I didn't strip down the DEC arm.  Didn't try switching
Autostars either. 
Mike here: Certainly an error in the AutoStar (or encoders) or an error in DEC training data recording could create a downward drift. Another possibility is an error in where the AutoStar thinks it is. Check the site location.

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