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ETX CLASSIC FEEDBACK

Last updated: 31 March 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:	ETX-80 slews down but not up
Sent:	Sunday, March 31, 2013 11:34:19
From:	D Webb (dlw_insulin@hotmail.com)
I am hoping you might have some opinion, maybe something 
about this on your website. Not sure this prob can be fixed 
by training, etc. Thinking I can take it apart and fix if needed.

Dominic
Mike here: Have you tried fresh batteries? Have you done a CALIBRATE MOTOR and TRAIN DRIVES?


Subject:	Help - ETX90 Slewing Wrongly
Sent:	Sunday, March 31, 2013 10:06:11
From:	Yihan Goh (gohyihan@gmail.com)
I have a problem with my ETX90 and would be very grateful for any
advice.

My ETX90 is an old model, not the newer ones with the red dot finder.
After I put the scope into 'home' position and select 'easy align', the
scope attempts to slew to Sirius. However, the scope then raises from
its horizontal position to almost vertical. Now it tries to go beyond
the forks but the finderscope bracket blocks it, leading to a stall.

This is very odd because Sirius is certainly not overhead; it is in fact
quite low in the west at this time. I checked to make sure my time,
date, location settings, etc, are all accurate. When I turned on the
scope again and tried to slew to Jupiter without alignment, it tells me
it hasn't risen despite it being quite low in the west...

So something tells me that there's something wrong with the software...
I then thought maybe for some reason the firmware doesn't cover 2013, so
I randomly entered a date, 2003, around the same month and date, but it
also does the vertical slewing thing.

One thing I had done before is that I had the OTA deforked in exchange
for a newer one. But I think it had worked after the change.

Any help would be appreciated. Thanks!!
Mike here: See "Q. My telescope has gone berserk. It slews until it hits the hard stop in either azimuth or altitude. It behaves erratically. What do I do?" on the ETX FAQ page on the ETX Site home page.


Subject:	Malfunctioned AZ Motor Drive on ETX 60
Sent:	Saturday, March 30, 2013 21:00:33
From:	B1outdoors@aol.com (B1outdoors@aol.com)
Tonight (and for the first time) I experienced a failure of my ETX 60
telescope to travel left or right in the azimuth. While attempting to
perform an Easy alignment the 494 controller initiates a search for the
first star, but will only travel along the altitude position. Is there a
repair that I can make on my own, or does this old telescope need to be
repaired by a Meade technician. Thanks for your reply.
 
Billy
Mike here: Have you checked for an obstruction by unlocking the axis and slowly moving the telescope by hand? Don't force it in case the obstruction is a wire. If the telescope moves freely, try replacing the batteries. Do a CALIBRATE MOTOR whether or not you swap the batteries. If that doesn't help, try a RESET.

And:

I tried your suggestions, but to no avail. Could it be that the
motor/gear system for the AZ is worn out, or just not engaging due to
sudden internal damage? I appreciate your website and all the help you
provide, particularly for my ETX 125 PE. Thanks!
Billy
Mike here: Of course, anything is possible. With the axis unlocked, can you hear any motor sound when running it at the fastest slew speed in either direction?

And:

I could hear motor sounds in either direction, which lead me to the
decision to disassemble the bottom cover and examine all gears. They
were intact and not damaged, but I noticed that a plastic part, which
appeared to be a guide arm had suffered a broken "hooked-shaped" end to
it. I located the small piece of plastic, but could not reattach it
firmly. Upon reassembly of the components, I still experienced no AZ
movement. Therefore, I have decided to scrap any further plans to try to
repair the ETX 60. My prior contact with the technician at Meade
determined that they do not service the ETX 60 or sell any parts, due to
the old age of manufacture and out of market status. Thank you for your
attention to my inquiries. I'll just use the the ETX 60 as a terrestrial
scope manually, and continue  to enjoy my ETX 125 PE, along with other
scopes that I have in my inventory.
Mike here: A broken motor mount might be repairable. There are some articles on doing that on the Helpful Information: Telescope Tech Tips page.

And:

Thanks very much. I will research the articles and see if there is
anything else that I might be capable of doing to correct the problem.


Subject:	re: ETX 125 motor unit failure
Sent:	Friday, March 29, 2013 13:23:32
From:	richard seymour (rseymour@wolfenet.com)
Based upon a decade of failures, your motors are probably still OK.
(think: when it first failed, did BOTH motors perform the "test motor"
motion?)

What usually fails on the Meade scopes is one (or both) of the power MOS
FET driver transistors for one of the motors, usually by internally
short-circuiting.
The excessive current that demands then proceeds to blow one (or more)
of the copper circuit board trace into vapor (an expensive "fuse")

If you had a 2 or 3 amp fuse on your 12vdc power feed, it would've
popped and prevented the collateral damage ... the internal batteries
have no such protection: smoke.
(your power supply probably "sagged" due to the high load)

I'm attaching the schematic (taken from Meade's patent document) for
each motor card.
The power FETs are both dual units, for a total of 4 power FET gates for
each motor.
Over the years, Meade has used different pairs of FETs.
The schematic shows what appears to be F9933 and F9936 by International
Rectifier or Vishay. (it's possible i'm mis-reading the first scrawled
digit.. since:)
They have also used  SI4936  and SI4947
International Rectifier's F9953 and F9956 will also work, as will
Fairchild FDS6982  and  Fairchild FDS6975

IF one of the FETs is blown, they frequently crack or bubble the plastic
of the chip.

Figuring out if a trace is blown away is detective work... compare the
two motor boards for differences (or suspiciously clean stripes on the
board), and also check the board with the power switch and sockets.  You
can "bridge" a missing trace with thin wires gently soldered to the
remaining traces.

good luck
--dick

photo


Subject:	A right angled finderscope for the ETX range
Sent:	Wednesday, March 27, 2013 16:23:30
From:	Paul Gibson (Paul.Gibson@arm.com)
I just read Glyn's enquiry re a right angle finder scope for an ETX. I
dislike the additional contortions that using my ETX125 PE's red dot
finder requires, and so looked for a right angle finder scope....and
found one from Orion. By the way, the Orion store in Cupertino, CA
(10555 S De Anza Blvd...I travel to the US a lot) has great staff and
very good special offers. I am travelling back to the UK, today, with a
prototype binocular mount for $30, and more Kgs of metal than I care to
think of!

Back to the finder scope track, I looked at the Orion right angle finder
with the illuminated reticule. Looked very good...but, how to attach it
to the ETX125? There may be great solutions on Weasners which I could
have plagiarised..but half the fun is coming up with a design and
building it yourself!

In the absence of attachment holes (and I was not going to drill some in
the OTA), I have made a saddle to which the finder scope can be fixed.
This is of aluminium angle and wood, with a Velcro band to keep it tight
to the OTA. Currently, it is awaiting its first light ...and I will
either change it dramatically (the Velcro is my answer to the added
weight of a metal belt attachment mechanism), or consider it a success,
and will post it on-line. i.e. I don't mind adjusting it at the start of
each observing session, but it must be solid enough to resist any
vibrations during an observing session, to avoid re-adjustment during
the night.

This may not work for the smaller ETX90 EC, but if it does work for the
ETX125, I'll get back to Weasners...

Regards,

Paul


Subject:	ETX-125PE LNT Battery
Sent:	Wednesday, March 27, 2013 09:45:04
From:	goodfortune72 (goodfortune72@gmail.com)
I'm trying to find the correct battery for my LNT on my ETX-125PE. The
manual says CR2023, but when I opened the LNT the existing battery is a
CR2025. I've also read the battery should be a CR2032. Any idea which
one I should get. Any help greatly appreciated. Thanks. 

from space!
Mike here: I believe the CR2025 can be replaced by the slightly thicker and longer lasting CR2032. I'd recommend taking your existing battery to your local Radio Shack and ask them for a replacement. My experiences with Radio Shack is that they know batteries.

And:

Thanks. So that 2023 model is just a typo in the manual. I'm going to
pick up a 2032. 

from space!
Mike here: Search the ETX Site for "CR2023" and you'll learn what others have learned.

And:

Thanks. Think I found the information.  Your site is always helpful. 

from space!


Subject:	ETX 125 motor unit failure
Sent:	Sunday, March 24, 2013 11:37:38
From:	John Urbanchuk (jurbanchuk@gmail.com)
Earlier this week at a starwatch my ETX 125 (7 years old) unexpectadly
gave me a motor unit failure and started testing the motor drive.  I
turned the scope off.  When I got home I tried it again with new
batteries instead of the 12 volt adapter I had been using for several
years.  The red light turned on and the unit stared smoking.  I am
afraid I fried the motor.

I checked out the Telescope Tech Tips page but could find no real
solution.  My question is can this be repaired and is it worth it?  Or
should I just remove the OTA, put dovetail adapters on it and buy a new
Meade (LX80) or Celestron computerized mount? Or, just buy a new scope
(the OTA is still good)?

Thanks,

JMU
Mike here: Do you know WHAT smoked? The motor or a circuit board? If the motor, you can try the article "Replacement Gears source" on the Helpful Information: Telescope Tech Tips page. As to the culprit, low battery power can cause a MOTOR UNIT FAILURE. Replacing with fresh batteries will solve that problem (don't forget to CALIBRATE MOTOR). However, if the batteries were inserted incorrectly, frying a component can occur.

And:

Thanks.  Don't know what smoked; my guess is the motor because I smell a
distinct burn residue odor.  Is there a relatively easy way to find out?
I am pretty certain that I inserted the batteries correctly.
Mike here: The easiest way to check for burnt components is to do a visual check of the circuitry. You will have to open up the base and fork arm for the visual inspection.

And:

Again thanks!  Are there instructions to do that on the Tech Tips page?

BTW, your Cassiopeia Observatory page is great.  I am very impressed
with your images.  I got an iPhone adapter for Christmas and have been
learning how to use it.
Mike here: Sorry for the delay; watching IU at the NCAA Tournament. Glad you like the observatory site. Thanks. Lots of disassembly tips on Telescope Tech Tips page.


Subject:	etx 105 dec motor
Sent:	Sunday, March 24, 2013 02:48:08
From:	Massimo Corbisiero (mc9613@mclink.it)
I have an older  meade etx 105 (2002 construction) with hand control 497

Dec motor don't function but hand control don't return an error message
as the motor work well.

Is this a know problem?

Do you know where I can buy etx dec motor for substitution?

Thank you
Massimo
Mike here: See the article "Replacement Gears source" on the Helpful Information: Telescope Tech Tips page. Failure could be due to many causes including broken/disconnected wires, loose motor mount, broken teeth, etc. Be certain you have eliminated other causes before you replace the motor itself.


Subject:	etx90 finder
Sent:	Monday, March 18, 2013 14:50:05
From:	Glyn Evans-Hughes (glynevans-hughes@hotmail.co.uk)
I recently dusted off my ETX90EC from the attic after deciding to
restart an old hobby. Unfortunately I find that like most things you buy
these days you can no longer get the parts that you probably should have
got a few years back. One being the field tripod as I have been using a
standard cheap one I adapted albeit quite shaky. Money at the time
though was extremely tight, hence the hobbies having to take a back
seat.

Nevertheless, I have been looking for a right angle finderscope. As
you know this is no longer available so I am looking for a viable
alternative that will help my ageing back from trying to contort to
positions it no longer wishes to!

If you could possibly shed a little light on what is feasibly available
now (and available in the UK) it would be most appreciated.

Thanks.  Glyn.
Mike here: Yep, finding a replacement right-angle finderscope for the ETX will be a challenge. However, using one of the finderscope tips on the Helpful Information: Telescope Tech Tips page, you should be able to adapt a right-angle finderscope to the ETX. There are several UK dealers on the Astronomy Links page; perhaps one of them can help you.


Subject:	Meade ETX 125 aluminum carrying case
Sent:	Monday, March 18, 2013 08:40:28
From:	Desiderio, Dominic M (ddesider@uthsc.edu)
Do you know where I could purchase a Meade ETX 125 aluminum carrying
case?

Thank you for your help.

Dom

Dominic M. Desiderio, Ph.D.
Professor, Department of Neurology
University of Tennessee Center for Health Science
847 Monroe Avenue
Room 117
Memphis, TN 38163
Mike here: There are many generic case dealers on the Astronomy Links page. There are also DIY case tips on the Helpful Information: Telescope Tech Tips page. If you really want the discontinued Meade case, you can try telescope dealers like OPT. Alternatively, try Telescope Warehouse (link on the Astronomy Links page).

And:

Thanks, Mike, for your rapid and helpful reply.
I appreciate it.

Dom


Subject:	etx90ec
Sent:	Monday, March 11, 2013 09:33:02
From:	Lowell Templeton (wlt3305@gmail.com)
I have a etx90ec telescope my father gave me several years ago. I have
never used it but recently moved to an area that allowed for grat night
time sky views. My problem is I have never used a telescope before.
Telescope is equipped with autostar and electronic focuser. My problem
is that when I look through eye piece all I see are extremely blurred
images. Even with electronic focuser images all remain very blurred. I
have pointed telescope all over the sky and can not make out anything.
When I do get a blurred round image in scope there is a black dot in the
center. Do you have any advice or possibly any contacts in my area (we
have no local astronomy club here) that could help me figure out how to
use this scope. I am willing to pay someone provide instructions on how
to use scope and astronomy in general (either in person, skype, or
email). Any help or input you could offer would be greatly appreciated.
Thank you,
Lowell
Mike here: Jupiter (high in the sky) or the moon (showing up soon) should help you achieve a focus (assuming the focus mechanism is working). You can also use a very distant land object. If you see the large central dark area, you are seeing the secondary mirror and the image is way out of focus. Do not use the focus to try to change the magnification. Stars will always appear as pinpoints of light. But you should see Jupiter's disk and up to 4 moons of Jupiter.

And:

thank you very much for feedback. I will wait for a good moon to focus
in on and see if I can determine problem.
regards,
lowell

And:

I removed electronic focuser just to do it by hand first in
case problem has something to do with electronic focuser. When I use
handset control that came with focuser it makes no noise and gives no
indication it is doing anything at all (new 9 volt battery is in place).
When I plug cord into autostar handset instead and get to focuser menu I
can hear the focuser making noises like it is working as I press up/down
keys but there is no change in what I can see (or not see) looking
through eyepiece on scope (26mm eyepiece).

thank you again your help and input.
regards,
lowell
Mike here: Without the electric focuser attached, if there is no focus change when rotating the focus knob, it could be that the focus rod has become detached. There is an article about that on the Helpful Information: Telescope Tech Tips page.

And:

thank you. I will look for it in owners manual.
Mike here: You won't find that in the manual. Check my ETX Site.

And:

thanks Mike. Your web site is awesome. I'm sure I will learn a lot more
about my scope and problems through it than owners manual.

Take care & have a great day,
Lowell

And an update:

got it working! Thanks so much. Luckily it was not detached focus rod as
I am sure I would have done more damage than good to scope. After
removing electronic focuser I was able to focus on near and far objects
just manually turning focus knob. After looking at unattached electronic
focuser but plugged into autostar handset It was clear then that while
the electronic gear wheel inside was moving and in contact with larger
gear that slips on knob it was simply spinning the gear without moving
the focus knob. I had not noticed even noticed the small hex hole on
larger gear wheel and after tightening it up aligned with rear of focus
knob it worked perfect. For a complete beginner like me it was exciting
just to be able to see clearly boats out at sea whereas before I could
not even tell the ocean from the sky. Thank you again. I will be
visiting your web site often for more tips and input from others far
more experienced than myself. I can't wait for next clear night.

Take care,
Lowell

And more:

One last question. Don't mean to bother you. What would you recommend as
best eyepiece for the etx90ec aside from the 26mm that came with it?
Something for best detail and sharpest view of planets rather than land
objects.
Thanks again very much. Your input is greatly appreciated.
Lowell
Mike here: There are several eyepiece articles on the Helpful Information: Buyer/New User Tips page. Just keep in mind the theoretical maximum magnification. If you are unsure how to calculate that, see the ETX FAQ page.

And:

got it. thanks again.


Subject:	Image Shift Due to Loose Primary Mirror - EXT125EC
Sent:	Saturday, March 2, 2013 14:39:17
From:	Albert C. Douglas (a.c.douglas@embarqmail.com)
After reading through all of the posting on this wonderful site, I
finally got up the courage to tear into my older EXT125EC.  I did a
complete disassembly, looking for slop in the focuser, binding due to
lack of lubrication ect.

What I found on mine was that the primary mirror was loose, I felt it
when cleaning out the grease in the tube.  This may have been due to the
fiber washer under the holddown ring shrinking as it dried out in the
dry air of the Nevada desert, I don't remember image shift when the unit
was new but it had gotten extreme over time.

The fix was very simple, I just tighten down the holddown ring holding
the primary mirror onto the mirror carrier.

I now have no perceptible image shift.

Thanks for a great site.


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