ETX-125EC USER FEEDBACK
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Last updated: 30 September 2002
This page is for user comments and information specific to the Meade ETX-125EC. Comments on accessories and feedback items appropriate to other ETX 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 and I'll post them. Please use an appropriate Subject Line on your message. Thanks.


Subject:	Re: ETX125 image shift/ dec clutches
Sent:	Sunday, September 29, 2002 16:51:40
From:	sherrodc@ipa.net (Clay Sherrod)
To:	Andrew
unfortunately there are NO specs on image shift, but what you are
describing is very excessive; it sounds like they substituted an older
OTA onto the newer fork mount when you wanted the new version
back....somebody really got to you it sounds like.  You can minimize
that shift somewhat by unscrewing the blue tube from the back of the
rear cell, exposing the mirror; the mirror can be detached from the
focuser pin and then pulled off the long baffle tube;  then lubricate
the baffle tube/sled heavily with Mobile Red Avionics grease or similar
and work the mirror back and forth up and down the baffle to even it
out.

I normal discourage users from doing this, but down under you likely
have little choice...you have very much excessive mirror shift.

Regarding the DEC fix; it does come apart very similarly to the older
models but much care must be used to assure that the ORDER of the pieces
is maintained when putting back in...sounds like they have way too much
grease in there.

Good luck!

Clay
----------------------------------------
Dr. P. Clay Sherrod
sherrodc@ipa.net
Arkansas Sky Observatory
www.arksky.org

----- Original Message -----
G'day clay
About 9mths ago i bought a new ETX125 but due to a bent shaft in the RA
drive it had to go back for repairs. It was one of the new models with
alloy forks etc. When it was returned to me it had been swapped for an
older model so i asked for my original back. This was not forthcoming
for whatever reason but i did end up with another unit ( after seven
weeks delay ). This last unit appeared to have been reassembled from
parts sent ex the USA (which seems to be the policy in Australia ). This
new unit exhibited greater image shift relative to my original and i
queried mikes site re this. ( It was nowhere near the 1/2 FOV of a 26mm
Plossl some people had reported earlier ).

I have persevered with this unit ( as the optics still appear to be
quite good and the goto is reasonably accurate ) Over time i have also
noted that the mirror has freed up considerably relative to when i first
started. I finally got round to doing some checks on the weekend, using
an 8mmEP to view a 5mm calibrated grid target at 25m range to get an
idea of the current shift.

I checked by watching the position on the grid relative to the edge of
the EPs FOV.

When moving the mirror through any reasonable distance i get approx 18mm
shift ( ~2.6 mins ). When just rocking the mirror too and fro through
the focus point, the shift is about 10mm ( ~1.4 mins ).

What is normal/ expected tolerance?

Also, what is the normal mode for quoted shift. Movement when mirror
fully moved or movement when mirror "rocked"?

On top of this, i occasionally notice that the mirror seems to ooze a
little after initial focussing, especially when pulling the mirror back
towards the rear cell. Is this normal?

Sorry for all the basic questions but i have no prior experience with
this type of scope and getting a straight answer as to normal
behaviour/absolute magitudes has proven frustratingly difficult.

Also i am beginning to notice that it takes more pressure to lock the
Dec clutch. I have read most of the stuff on mikes site re cleaning etc
but everything relates to the older models. Is there anything special in
the new type unit to be wary of. ( I am a Mechanical Engineer and have
no problems with jobs like this but i dont know whats inside the forks
and would prefer not to learn the hard way.) Is there likely to be a
pictorial "how to" coming out for this or is it getting too complicated
for the mugs?

yours A

Subject:	ETX 125 Image Shift
Sent:	Friday, September 27, 2002 11:32:18
From:	beng3@mindspring.com (Ben Crowder)
What is considered an acceptable amount of image shift during focusing
for an ETX 125?  My scope exhibits what I estimate to be between 7 and 8
arc minutes of shift.  This makes it hard to focus at high powers.  I
called Meade customer service and was told that that amount was not
unusual and that little could be done to remedy the problem anyway. 
What do you think?

Thanks,

Ben Crowder
Mike here: The ETX optical design, like most Maksutov-Cassegrain telescopes, will have some image shift. At the maximum usable magnification you should not have a problem focusing. If you want to try to improve it, see the Telescope Tech Tips for an image shift article.
Subject:	Recommendations on ETX-125EC with UHTC
Sent:	Tuesday, September 24, 2002 18:47:01
From:	sasakit@msn.com (Todd Sasaki)
I read the email dated 20 Sep on the problems with the new ETX-125EC
with UHTC and would like to know if the stepping characteristic would
have a large impact on CCD photos.  Is there a remedy for this problem? 
I don't have a derotater so I'd like to use it in the alt az mode. 
Would I be better off going with the 105?  Thanks.

Todd
DC
Mike here: Mounting in Polar mode is the best solution when you want the most accurate tracking without the need for a field derotator.
Subject:	ETX125-EC
Sent:	Tuesday, September 24, 2002 12:35:08
From:	HSchilling@birch.com (Schilling, Henry)
I just got a 125 for $650.00. Cheap I think. Can you tell me what Dr.
Clay is charging for a supercharge now?    thx   hjs

Henry J Schilling
Mike here: See the "ETX Tune-up Service" (linked from the ETX Site home page) for current info.
Subject:	Obs, Barlow Lens
Sent:	Tuesday, September 24, 2002 2:26:13
From:	p.v.camerijk@wxs.nl (Peter van Camerijk)
Here again some news from holland. Yesterday I finally got a good
opportunity to use my complete set-up for my ETX 125. After buying the
EQ-6 tripod and the celestron wedge AND training the motors with a
laserpointer (works great!!!), I finally had a night of good clear
sky!!! And everything worked superb......I did a not so good polar
alignment (to eager to use the ETX.....) but still the autostar worked
great!!! Allthough the moon was very bright and so were the lights of
the neighbours gardens and the lights of Rotterdam harbour (I know it is
not really a challenging neighbourhood for someone who likes to look at
faint objects in the nightsky!!!) I still got some beautiful views of
M57 (of course... it is one of my favorites), M81 and 82,
M31(obviously), M27 and M51. Especially M27 (the Dumbbell Nebula) was
super. I watched it with a nebular filter and that gives you so much
more detail.....even with my Meade SWA 13,8 mm I got a good view (how
would that be when there is no moon and no light polution???).

I used the high precision mode and polar alignment and this works very
good: every object was well in FOV of my Meade 26 mm superp[lossl. I
only have one question: is there a big difference between the achromatic
barlow (the shorty for the ETX) from Meade and the apochromatic barlow
from Meade??? I used yesterday my SWA 13,8 mm with the shorty barlow and
the views from the moon were awesome........I got turn my complete
eyeball about 180 degrees (well allmost!!!). Normally I use my very old
and ancient 6 mm orthoscopic oculair (still 0.96 inch dia. ha, ha, ha)
and under very stabil conditions I can use my 5 mm orthoscopic oculair
(I think it comes from the Egypt, some 3000 years ago). But now I have
my SWA 13,7 with teh barlow I am afraid the old ones won't be used
anymore!!!!!

Well you see it was worth while yesterdayevening!!!! I hope I have given
here an impresion of a ETX 125 user who is absolutly satisfied with this
magnificent bleu superoptical device!!!!!! But I must admit that a good
tripod and wedge makes all the difference!!!!! It is so importent to
have a stabil platform to optimize the use of the ETX 125: at this
moment nothing shakes, jitters or moves during my observations including
focussing (although I did buy the focus cable from Scopetronics (it did
take a little bit of time before it came here in holland.....about 4
months!!!!!!!!!)).

I hope for more beautifull clear nights for everyone with a telescope
and thank you for your supersite: I have to look for it everytime you
update it!!!!!!

Peter 
Mike here: Some longer Barlow Lens than what Meade recommends for the ETX may not reach a focus with all eyepieces. I've only used the Meade shorty one so can't compare the other one.
Subject:	ETX-125EC with UHTC
Sent:	Friday, September 20, 2002 6:39:00
From:	sellerd@optonline.net (Stephen Ellerd)
The new 125 I have tracks silently but I have discovered a possible
drawback to the silence. Before all of the ETXs had the distinctive
high-pitched noise while tracking and the units tracked smoothly. Now it
seems like the tracking is in small discreet steps as you would expect
from stepper motors. It tracks very accurately but the discreet step
moving of objects in the eyepiece lead me to believe that the new ETX is
not as well suited for astrophotography as was the older model.  This is
just an observation and I plan to call Meade today to see if this is
normal.  Maybe the silence comes at a price.

I already had to use Dr. Clay's lens cleaning solution on the new
coatings since I got sticky sap or pollen on the corrector plate.  I am
pleased to report that if you follow his directions the results are
perfect.  A slight breath on the lens show no streaking or spots at all.
The recipe is on his site is on http://www.arksky.org under GUIDES.

Steve
New York
Mike here: In alt/az, there is always "a stepping" when tracking, even on older models. If you mount in Polar mode the tracking is only on one axis so there is no step motion.

And:

The stepping I'm used to is almost imperceptible. The kind of stepping I
saw on the 125 was big jumps like watching a second hand on a clock. 
The RA axis on the 125 was too tight and was indexing according to the
Meade techs. Anyway I returned it today for an ETX-105EC with standard
coatings.

So far at this dealer I have had two ETX-125ECs with clutches that would
not disengage.  Today when I bought the 105 and opened the box before I
left the store this time and found that the Styrofoam inserts in the box
had shifted (Probably with UPS's help).  The OTA was bent the way it
shouldn't go.  The finder ring was buried under the arm.  The second one
I opened had the finder ring just cracked not wedged under the arm.  The
packaging shifted on this one also. The scope I finally wound up with is
a 105 that was loaned to me while I was waiting for one to come in.  It
is the only good scope I have run across in the 4 or 5 scopes I tried to
buy.  The RA axis has very little friction, there is negligible backlash
and the goto accuracy was 100% tonight.  There was no jumping of stars
this time.  I took the DEC adjustment knob off and found that the clutch
bushing was noticeably bigger that the 125 - go figure.

I could have just settled with the first scope I got and either sent it
to Meade, or even better to Dr. Clay.  At least if Dr. Clay
super-charged it I know it wouldn't come back with more problems than it
left with.  So here I am with a 105.  IMHO it is the best designed of
all the ETXs.  It's frame can support the OTA and the RA axis is smooth
as it should be with radial bearings.

Thanks for you help,

Steve
New York.

Subject:	great site
Sent:	Sunday, September 15, 2002 23:14:12
From:	Houztx17@aol.com
The etx 125 is the first and only scope I have ever owned, and thanks to
your site and the contribution from DR Clay I have a greater
understanding and appreciation of the capability of the 125. this is the
second 125 i have had the first was plagued with problems, and after
some battle with meade they replaced it with a new version this one to
has had its problems but meade has worked with me and resolved those
problems if only meade would take a look at some of the things you and
your supporters have done they may learn something. i have to say that
even with the problems that i have had, the enjoyment i get out of it
pales in comparison to the problems that seem to come with it. my niece
and nephews love the scope and are always asking when i will bring it
back i try not to dissapoint.

once again your site is wonderful keep up the good work
                                                       
                                                              John

Subject:	[ETX-125] Power supply ?
Sent:	Sunday, September 15, 2002 12:25:25
From:	titeuf@meloo.com (titeuf)
Hello Mike and congratulations for your site. It's really interesting
and so complete that it is not easy to find the right information in a
few second... Excuse me if the answer to my question is available in
your site :-)

I would know the power supply for my scope ETX-125, in order to buy an
adaptator like 220VAC/12VDC (I live in france). I found one on the
internet site 

http://www.fr.conradcom.de

but the maxi power is 1 A. Is that enough for my ETX-125 and the
Autostar ?

Thank you for your answer ;-)

Best regards.

Titeuf

Subject:	3 years old ETX-125EC
Sent:	Saturday, September 14, 2002 10:21:46
From:	vinckkw@pacific.net.sg (Vincent Kee)
I am thinking of purchasing a 2.5-3 years old ETX-125EC, is there
anything I should particularly look out for or concern about, wben
comparing a scope of that age with the current ones? Any major
differences?

Also, thanks for the wonderful website. 

Thanks
Vincent
Mike here: There are some internal differences mechanically. Whether they will be an issue depends upon your expectations. I'm still using an original design ETX-125EC and it works OK. One thing to check for would be "image shift" during focusing. There was a problem with some early ones that caused excessive image shift. It could be corrected but the telescope had to be returned to Meade for that.

And:

Thanks! I do understand about those mechanical differences (heard that
the newer ones has aluminum fork or something), but how about its
software? I remembered that for the Nexstar 5, the older ones do not
have the moon in it and that's quite a major flaw. Is there major
problems too on the software of the older 125?

By the way, I was leaning towards the N5 until a good deal on the
ETX-125 came along. But that's not enough..another reason is because the
N5 site isn't as great as yours!

Thanks
Vin
Mike here: Depends upon the version of the Autostar. But if you have a Windows capable Mac or PC and can make or buy the #505 cable, I would suggest upgrading the Autostar ROM to the latest on Meade's site.
Subject:	Followup to ETX-125 with UHTC
Sent:	Tuesday, September 10, 2002 9:29:15
From:	s_ellerd@yahoo.com (Stephen Ellerd)
After a few phone calls to Meade and an email to Dr. Clay, the result is
that the scope is perfectly normal. If my calls to Meade indicated that
stiffness in the RA axis is normal I would have been satisfied. I was
persistant with Meade and they finally admitted that the RA axis
stiffness is normal. Dr Clay had already indicated that this is normal
in one of his earlier email answers here. I can relax now and just enjoy
the scope. Not only does it track silently but I had M57 in the center
of my 26mm eyepiece for about an hour and a half last night. I put the
ETX-125 UHTC up against my Nexstar 5 on the Dumbell Nebula and the Ring
Nebula. The ETX had much better contrast and detail but both scopes
showed about the same brightness, keeping in mind that the Nexstar 5 is
an F/10.

After using the Autostar for awhile I'm spoiled. The Nexstar computer
pales by comparison IMHO.

Steve

New York 

Subject:	baby steps.
Sent:	Sunday, September 8, 2002 0:18:19
From:	premal@ruksun.com (Premal Jhaveri)
today i had my first baby steps with my 125ec. I saw the first light of
M13, from where it left millions of years ago . you can understand my
excitement :) I used the standard 26mm eyepiece.. i also tried with the
2x  barlow and the view was stunning. I have a question, My view moves
when i try to focus.. the stars actually moves to left to right when i
focus in clockwise and anticlockwise.. is this normal or something wrong
with telescope ??
 
btw  - I live in bellevue WA.. 
-Premal
Mike here: Some image shift is normal with Maksutov-Cassegrain designs as a mirror is moved to change the focus. And not to burst your bubble but M13 is only 25,100 light years away, not millions.
Subject:	Focus Knob ETX 125
Sent:	Saturday, September 7, 2002 18:12:23
From:	DENISEPETRUS@aol.com
Brand new scope and focus knob is loose on shaft. It will not focus.
What is the size of the hex key set screw holding the knob on the shaft?
Is it metric or standard? I have tried numerous keys and have not found
one that will fit. Thank you.
Mike here: Seems to be a 1/16th-inch.

And:

Thank you very much for your quick response. I have tried a 1/16" hex
key and the wrench slips on the key. I have owned the scope for one
month and have used it only twice.  I have been educating myself reading
your latest book I recently purchased, Using the Mead ETX.  I have only
used the focus knob a couple of times, and cannot understand how the
knob slips on the shaft when the key appears to be tight. To your
knowledge is this a common issue with other ETX owners. I am at a loss
at to how to fix this problem because the key you have suggested does
not seem to help. Once again thank you very much for your help.
Mike here: This is not a common problem but what is a common problem is that the key is not inserted all the way into the hole in the small screw. Be certain you are getting the key properly aligned and inserted completely.

And:

Because of the sensitivity of the focus knob and the inablility to fix
it, I am considering returning the ETX 125 and purchasing the LX90. Are
you aware of any issues on this model? Are the optics compararable?

I enjoy astronomy but am not the type of person who easily handles
frustrating issues like that of the focus knob.

Thank you.
Mike here: From reports I've seen, the LX90 is a fine telescope. Of course, it is much larger than the ETX-125EC.

And:

Took the scope back to Discovery store and they will send back to Meade.
I will, be receiving a new 125 within the week from them. I will stay
with this scope and hopefully  not anticipate another focus issue. You
are right in that the LX90 is approx 2 and 1/2 times larger. I prefer
the potability of the 125. I want to say thanks to you for all your help
and timely response's. Hopefully I will be back in business soon.

Subject:	ETX-125 Stops (below)
Sent:	Thursday, September 5, 2002 6:16:34
From:	bjboitnott@cox-internet.com (Boyd Boitnott)
Mike, thank you for your reply to my rather desperate question.

I found a loose piece of blue plastic floating around within the base
yesterday evening.  Turned out that the scope never reached the real
stops because of random contact with the plastic.  Without going into
details, I removed the plastic and now the 'real' stops work.

Thanks again Mike,
Boyd Boitnott
San Angelo, TX

Subject:	Re: ETX-125 Drive Skip Problem
Sent:	Wednesday, September 4, 2002 22:56:58
From:	sherrodc@ipa.net (Clay Sherrod)
To:	SCrask@qtww.com
The Meade fix is well worth the $75 and the problem you are encountering
is very common right now.  The small transfer gears are not properly
meshing under load as you have discovered and typically the $75 repair
is extensive, merely replacing the entire motor/encoder/gearbox assembly
with a brand new one.  Trust me on this one....you need a new gearbox
and Meade is the cheapest (....did I also mention THE ONLY??) source.

While in, ask them to check both drives carefully and collimate the
scope. Get the most for your money.

Best of luck......

Clay
----------------------------------------
Dr. P. Clay Sherrod
sherrodc@ipa.net
Arkansas Sky Observatory
www.arksky.org
And:
Dr. Clay,

Thank you very much for your assistance and very quick response.  This
seemed to me like something I could not repair, but maybe someone had a
tip for a little bondo here and we're off and running!  I take it from
your response there is a known defect in that vintage of dec drives, but
I couldn't find a reference to it on Mike's site.  Maybe there's a
market for a re-designed Dec drivetrain with a real motor/gearhead
assembly.  And a new diecast fork to go with it, and a new base plate...

Off to Meade it goes.

And to Mike - thanks again for assisting on this.

Simon 

Subject:	ETX-125EC with UHTC
Sent:	Wednesday, September 4, 2002 22:06:34
From:	sellerd@optonline.net (Stephen Ellerd)
I just got an ETX-125EC UHTC today.  I was very enthusiastic about the
new coatings, aluminum mount and ball bearing on both axis.  Much to my
dismay the RA axis clutch is tight even when it is loosened.  The nice
ball bearings don't do me much good if the whole scope turns on the
table when I'm trying to turn the scope in RA.  I called Meade and they
instructed me to reset the Clutch lever making the clutch looser.  This
did no good at all.  I also fumbled with the allen set screw on the
clutch lever for awhile.  I could not get the wrench in the hole.  It
seems the person in Mexico where it was assembled broke the tip off the
allen wrench inside the head of the set screw.  I wonder if the quality
of the mechanism has suffered from being assembled in Mexico. I hope if
I order a new 125 it won't have the same problem or maybe something
worse.  I would also like to report that the DEC lock still does not
support the weight of the OTA. You have to set the DEC a little bit high
knowing that it will settle slightly.    I thought this might have been
fixed with the aluminum arm(s).  There is still noticable focus shift. 
Has anyone else experienced any of these problems with the "new" 125?

Now for the good news.  The scope can't be heard while it is tracking. 
The distinctive motor whine is completely gone.  The slewing the scope
does just b4 the object is centered is very smooth and quite also.  I
wondered if something was wrong since I was expecting the usual whine. 
This is a tremendous improvement for everyone that enjoys quiet while
looking at the heavens and the neighbors might appreciate it too.

I'm afraid the 125 is still not mechanically there yet.  I originally
ordered the ETX-105EC with UHTC but it is back ordered 1-2 months
according to Meade.  That's when I decided to get the ETX-125.

I borrowed an ETX-105EC and so far it is the best ETX I have used.  The
GOTO is very accurate.  The DEC lock works well and the ball bearings
make it effortless to move the OTA around on both axis.  The tracking is
not as quite as the 125 but is still more quite than the ETX-90.  It all
came together on the 105.

When I go back to the dealer tomorrow I'm not sure what I'll come home
with but I have a funny feeling it will be an ETX-105EC w/o UHTC.  The
coatings are harder to clean anyway and may only keep there efficiency
for 4-5 years (sour grapes).  Only time will tell.

BTW I have a Celestron Nexstar 5 but it has no forums like this one. 
That makes the scope kind of boring.

Thanks for your excellent site.

Steve Ellerd
New York

Subject:	ETX-125 Drive Skip Problem
Sent:	Wednesday, September 4, 2002 14:46:20
From:	SCrask@qtww.com (Simon Crask)
After much browsing of the archives on your site, I find I have an issue
with my 20 month old ETX-125 that may not yet have happened to others.
After a few months off for the "June gloom" of Southern California, I
brought out my 125 only to find it was making clicking noises in the
Declination drivetrain.  The drive would skip when motoring in either
direction, at any speed including 1, but most obviously from 5 up.  Once
a click happens it instantly loses alignment.  Much reading,
disassembly, cleaning, reassembly, cursing, reading, disassembly, etc.
ensued.  A call to Meade tech support resulted in a "we don't know -
send it to us along with $75" response.

The scope has been operating just fine both mechanically and optically
from the day I bought it (well, within its design limits anyway) with
constant updates to the Autostar and religious motor retraining.  I have
attempted to use it with a 35mm camera at prime focus counterbalanced
with a 3rd party piggyback / counterweight bracket - maybe that
overloaded the dec drive. The scope has seen action quite often since
new.

After disassembling again, I discover the clicking noise can occur when
testing without the OTA in place but a light load is applied to the
rotating arm.  It is not coming from the worm gear, or the big spur gear
to the motor drive as previously documented by others. Hmmm.  Open up
the gearbox and I find that the first countershaft mounts are sloppy,
apparently allowing the shaft to back away from the driving gear when
loaded, causing the little gears to skip, but no broken teeth or
excessive (visible) wear.  Plenty of lube on the gears and shafts, too.

At this point I'm looking for suggestions.  Has anyone else experienced
this problem?  Any fix other than $75 minimum and "from 4 to 8 weeks"
with Meade?

Thanks for a maintaining a consistently excellent site!
 
Simon Crask

Subject:	ETX-125 Hard Stops
Sent:	Wednesday, September 4, 2002 6:29:35
From:	bjboitnott@cox-internet.com (Boyd Boitnott)
I recently purchased a new ETX-125 plus accessories and am very
satisfied with the optics, tracking, and GOTO performance (after I
gained an appreciation of proper drive training!).

The RA hard stops are set such that about 12.5 deg of the sky is not
accessible.  I would like to reset these stops and would appreciate a
short description of where they are located.  I found your excellent
site as I was searching for information on the stops.

Thanks for you time,

Boyd Boitnott
San Angelo, TX

PS: I am not worried about invalidating the warranty.
Mike here: The hard stops are normally slightly less than 720 degrees apart (nearly two rotations in azimuth). Are you saying that you get less than ONE rotation of 360 degrees? If so, there is something wrong and since the telescope is new, I'd suggest exchanging it at the dealer.
Subject:	Re: Please Help
Sent:	Tuesday, September 3, 2002 6:07:24
From:	sherrodc@ipa.net (Clay Sherrod)
To:	Mark
You are unfortunately seeing the"reverse rebound backlash" as I have
coined it and some scopes are far worse than others.  There is not a
whole lot to do to correct this unfortunately since it is actually a
result of poor base and fork mount casting.....the worm gear is not
sitting in a plane aligned to the drive gear.  You might try shimming up
under ONE side of the worm gear (is this in the DEC or RA that you are
seeing the reversal??) in an attempt to realign the two....other than
that,try backing off the pressure (load) of the worm via the small flat
HEX head adjustment screw on the opposite end of all the transfer gears.

However be VERY careful in doing this, and always secure the worm shaft
via a pair of Visegrip needle nose pliers or similar.  If you are able
to turn the shaft when making any adjustment here, you can easily strip
out the delicate nylon transfer gears.

I would NOT advise anyone to make these adjustments on a new scope, but
in South Africa, you likely have no alternative.  Good luck and keep in
touch and I will be happy to walk you through further needs.

(your "Supercharge" in a box, so to speak....)

Clay
----------------------------------------
Dr. P. Clay Sherrod
sherrodc@ipa.net
Arkansas Sky Observatory
www.arksky.org

  ----- Original Message ----- 
  Hi Clay,

  I have dilligently read you posts on Mighty ETX, and wonder if you may
  help me. Whilst Extremely happy with my ETX125 (1 month old), I have
  had a few minor problems that I need a guiding hand with.

  My biggest problem is especially noticed at slow speeds. When I change
  slew direction in RA, the object in the 26mm FOV moves up or down,
  depending whether I am slewing left or right by about 1/10 of the FOV,
  and then moves normally.

  I have opened the base, and notice that there is a left right movement
  of the spindle with the worm gear. It seems to move perhaps 1/2 a
  millimeter backwards or forwards giving the impression that is is
  "climbing" over the worm gear. This movement seems to be allowed by
  the rubber "O" rings that the worm gear itself is mounted in at both
  end of the mounting.

  I have tried tightening the worm gear via the 2 allen key adjusters,
  but I am not sure how tight (or loose) they are supposed to be.

  Thanks for your time whether you can help or not.

  Regards

  Mark
  South Africa
And:
Thanks for the response. I am so glad that you have experienced this
before, I was starting too think I am too critical. I have attatched 2
photos of the worm, and you are right... it is the RA.

As you can see from picture A, I have marked the left end of the shaft
as the area where I can see the lateral movement. The other end displays
none. I have already backed off the adjusters (see 2 in Photo A), and as
a consequence, I have not had one motor failure since. I was getting
about 1 motor failure every half an hour previously. Since doing these
adjustments on the weekend, I have used the scope for about 5 hours with
none! So I inadvently solved another of my niggling problems. My current
problem is that I havent figured out a way of:

1. Knowing if the adjusters are tight enough.
2. Knowing if the alignment of the adjusters is correct. I am sure that
if they are not aligned, they could cause the problem you descibed
below.

Any Ideas on this?

The up and down movement in RA when I slew is less pronounced now. I
have also backed off the Hex nut tension. Originally my scope had about
950 clicks backlash in RA (as shipped) , and after slacking off, it
pushed the clicks up to 1400 (looks like too much). Subsequently, I have
tightened it a bit, and now I am getting about 720 clicks (Still no
motor failures so far....) on RA (Dicks patch Edit RA Training). Are
these figures about average? I am getting about 220 clicks on Dec so the
RA looks a lot less accurate.

PHOTO A
ETX base
In Photo B, below you see more clearly where the lateral movement can be seen at the left end (1 in Photo B) where the nylon bush moves up and down (in this picture view) within the black rubber "O" ring that can be seen behind the nylon bush. The other end (2 Photo B) is displaying no such movement. PHOTO B
ETX base
Thanks again for your help. Regards Mark BTW, I bought a Barlow for the ETX on the weekend, (I only have the standard 26mm Plossl) and was absolutely blown away with the views! I was able to resolve Epsilon Lyra's (I think the spelling is correct) double double into 4 individual stars which looked fantastic and really made my day (..ok night)! The Barlow took some getting used to from an eye relief perspective, but was immensely satisfying once I had it figured out. The views of Saturn, and Jupiter and its 4 visible moons (visible here at about 4:30 am) were absolutely stunning. I had previously (26mm Plossl) thought that Jupiter had only 3 visible moons, and a small Saturn-like band, but the Barlow resolved the band into the 4th moon. I am really enjoying the scope tremendously and learning in leaps and bounds. All I need now is to find out how to get enough sleep in 4 hours, as I am sky watching most of the rest :-)
And:
Hello Mark....this is good news.  The slack/slop you note in photo B is
likely where the majority of the reverse shifting is originating....it
sounds like you are on the right path.  To check the worm/driver torque
to assure that you are not too tight, it is done in two ways:

Take the large nylon gear (#3 in your first photo) and attempt to rotate
it by pushing it with your thumb while it is properly engaged with the
rest of the system.  If you cannot make it "give" a bit, then it may be
too tight;  second, rotate the main transfer gear (that is the very thin
large one in far upper right in your first picture, totally covered in
grease) and rotate it while watching gear #3 in the photo.  If that
latter gear does not begin turning within just a very short time, you
have binding.

By the way you MUST clean all that green grease off that transfer gear
pack in the upper right (all nylon)...that has so much grease that you
will surely and inevitably end up with that grease on the encoder which
is just behind that large transfer gear.....you likely already have some
on the encoder tick wheel and that ALSOcould be causing some of your
problems!!

Good luck....

Clay
And this:
Thanks or the insites! I will open up the base in the next day or so
(when I have a good 4 hour slot) and check the movement in the gears as
you suggest. I will let you know what I find. I really appreciate all
the help.

By the Way, what is the easiest way to clean the green grease off of the
gears? I havent managed to find Lithium grease yet, but I have Teflon
grease for Radio Controlled race cars which appear to use the same white
plastic gear trains. Do you think this would be okay? (maybe I will get
faster GoTos:-))

Thanks again for the help.

Regards

Mark

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