(Galactic Hitch-Hiker)

12/27/08 06:55 PM

ETX Problem - help required please

Hello Guys and Gals

A small problem has arisen with my ETX. The azimuth drive seems to have developed a problem.

When pressing the drive buttons to slew the scope, the altitude motors whirr as expected and the scope slews both up and down.

The azimuth motor only slews the scope clockwise - ie the right button works, but the left button seems to have stopped working and the scope does not slew anticlockwise.

Is this

1) A motor problem (ie a loose connection to the drive motor)

2) An Autostar handset problem

3) A cable problem (between the Autostar handest and the telescope base). BTW, reversing the cable has no effect so I'm likely to think the problem is either 1) or 2) above.

Thoughts and possible remedies please.

If you are aware of a particular problem and/or fix with a link on, for example, the mighty Weasner ETX site, I'd be most grateful.

Thanks in anticipation.

Arthur

Oh, and a Merry Christmas and Happy New Year!

(Postmaster)

12/27/08 07:01 PM

Re: ETX Problem - help required please

Are you sure you're not bumping up against the hard stop? The ETX-125 can only rotate so far to the left and right before you'll hit the stop. Starting in the proper home position (tube level, turned all the way counter clockwise) should keep this from happening.

(Post Laureate)

12/27/08 08:56 PM

Re: ETX Problem - help required please

If not the hard stop -- I would suspect the button on the hand controller needs cleaning-refurbishing--

Here is a repair kit to fix the buttons.
http://www.mgchemicals.com/products/8339.html

(Galactic Hitch-Hiker)

12/28/08 12:22 PM

Re: ETX Problem - help required please

Hi Guys

No, not hitting the hard stop.

Scope will rotate clockwise but then won't rotate counter-clockwise (or anti-clockwise as we say here in the UK).

Joe

The button on the Autostar hand controller - is this easy to sort out (ie the Autostar HC comes apart/fits back together again easily)?

If not, is this a new Autostar HC that I'm looking at (and if so - how expensive)?

Art

(super member)

12/28/08 03:15 PM

Re: ETX Problem - help required please

Art,

Check out Joe Lalumia's Post right above yours and order the referb kit it is well worth the low cost. A new Autostar controller can run $60 to $100 but buy the kit first. If you find an actual broken item in your controller, I can provide a cheap seller of repair parts but you have to know what part you need. Look at the conections on the cable and sockets for bent connections. The controller is not that complex. If you doubt your skill in taking it apart ask a Geek for help, they would love to look inside of something new. Computer Nuts are good for something.

Bill

(Galactic Hitch-Hiker)

12/28/08 04:36 PM

Re: ETX Problem - help required please

Hi Bill

Took the Autostar HC apart - cleaned the carbon pads with alcohol and the pcb. No sign of anything untoward there.

Re-fitted the HC back together again. It's not the buttons (and therefore not the Autostar HC) because the left button works when going through the setup menu (eg set date).

Definitely think that it is something in the ETX base - either a motor or a connection. I presume that the azimuth drive only has one motor which runs forwards and backwards for clockwise/anticlockwise (whichever way round it is).

How easy is it to dissassemble the base of the ETX to check out if there has been a fault like a loose wire?

Regards

Art

(Postmaster)

12/28/08 07:14 PM

Re: ETX Problem - help required please

Quote:

Hi Bill

Took the Autostar HC apart - cleaned the carbon pads with alcohol and the pcb. No sign of anything untoward there.

Re-fitted the HC back together again. It's not the buttons (and therefore not the Autostar HC) because the left button works when going through the setup menu (eg set date).

Definitely think that it is something in the ETX base - either a motor or a connection. I presume that the azimuth drive only has one motor which runs forwards and backwards for clockwise/anticlockwise (whichever way round it is).

How easy is it to dissassemble the base of the ETX to check out if there has been a fault like a loose wire?

Regards

Art

A word of caution while cleaning the carbon pads because on the bottom of the rubber button is a graphite coating..

You might have a Faulty cable check the connector pins on the base mount.

(professor emeritus)

12/29/08 09:34 AM

Re: ETX Problem - help required please

If all else fails, getting inside the scope can be done. Go to Mike Weasner's Mighty ETX site. There is a ton of information there as well as one that shows photos and how to get to the drives to check gears, etc. in "ETX 125 Azimuth and Altitude Repair".

John
John

(super member)

12/29/08 08:26 PM

Re: ETX Problem - help required please

I still think it is the controller. Think simple, mechanical first, electrical second. I would start with the rubber button graphite contact. I may have warn off. That is where that kit helps, it contains new contact material. First figure what two points the graphite touches to make the contact. Touch those two points with a small wire. If it works then get the kit. If not, check out the cable with an ohm meter, contact by contact to see it it is good. Check out the plug sockets it same way to see it the wires are good. I would think that if the opposite button works it is wiring because they probably do a simple reverse polarity to control the other button (positive makes the motor run one way, negative makes it go the other way). There are not enough wires in the cable to have 6 of them just for direction. It is probable 2 wires plus a ground (one wire for up/down and one wire for left/right).

Do you know anyone with an autostar unit. You could use theirs to figure out if it is controller or cable.

Last resort, open the base and look for a broken wire. The motor probably has only one or two wires (if one it uses the base as ground for the second contact. Check those first, There should only be one gear (the motor changes direction, not the gear), check out Mikes's site and see if it has a diagram.

Good Luck, Bill

(Galactic Hitch-Hiker)

12/30/08 04:38 PM

Re: ETX Problem - help required please

Cheers Bill

I'm persuing several avenues at the moment.

The scope is s/hand and had the azimuth drive replaced just over a month ago before I bought it. The guy who fitted it has been on holiday - he's in tomorrow apparently. Will give him a ring first thing and see what he says!

Art

(Galactic Hitch-Hiker)

01/14/09 12:59 PM

Re: ETX Problem - help required please

UPDATE:

Went to my local friendly telescope shop with the ETX and handbox. Plugged in another handbox - same problem. Scope slews in altitude in both directions but not anticlockwise in azimuth (clockwise slewing is OK). So, it's not the handbox and it's not the curly cable.

Took base of ETX off expecting to find loose/broken wire but none were obvious. A loose plug, but no, that's not the problem either.

So it looks like it is an electronics fault in the base of the ETX, so back to Telescope House it goes!

Steve (at TH) guesses that it is a driver chip on one of the boards inside the base.

Art

(super member)

01/14/09 07:40 PM

Re: ETX Problem - help required please

Thanks for the update... please keep us posted on the resolve.

(Galactic Hitch-Hiker)

02/20/09 04:59 PM

Re: ETX Problem - help required please

UPDATE:

Scope is now at the Telescope Hospital.

No prognosis yet as to problem and/or cost (so fingers crossed).

Art

(professor emeritus)

02/21/09 08:58 AM

Re: ETX Problem - help required please

Arthur-
Good luck at the telescope hospital. We all await news on the patients condition.

John

(Galactic Hitch-Hiker)

02/27/09 12:32 PM

Re: ETX Problem - help required please

Ok

Steve tells me that he fixed it this morning and that the cost is �60.00 including delivery back home.

Don't know what was wrong or how long this fix will last, but my baby is fixed and on her way home

Art

(Post Laureate)

02/27/09 01:50 PM

Re: ETX Problem - help required please

Great-- please tell us what he fixed when you receive the scope.

Clear Skies!

(Galactic Hitch-Hiker)

02/27/09 02:30 PM

Re: ETX Problem - help required please

Will do Joe.

I have a sneaky suspicion it was electronics, by Steve is a "good guy" and I'm sure that he'll let me know what was done.

From my description of the problem, Steve thought that it was a driver chip that had "blown".

BTW, have you read the thread posted by Nigel regarding some inside info from a Meade guy - QC issues? Link here.

Art

Just noticed, next post will be #300 Whooo!

(Galactic Hitch-Hiker)

03/11/09 02:38 PM

Re: ETX Problem - help required please

UPDATE:

My ETX came home today and seems to be working.

I did a "dummy" EASY alignment and the motors hummed and the scope went through the motions (although I have had several "Motor Failure" messages. I've done a reset and was immediately greeted by another "Motor Failure" message. Has been OK since.

It even pointed in the general direction of Venus and Mercury when asked to "GoTo", but it was mid-afternoon and I couldn't see the stars!

Typically, it has now clouded over to give 8 octas! Grrr!

Apparently it was a blown motor driver board.

Art

(professor emeritus)

03/12/09 01:30 PM

Re: ETX Problem - help required please

Arthur. Weather is rotten all around.

Last ''reasonably" clear night was last Sunday. Got out to check alignment of the replaced LNT on the 125PE. After adjusting to the limit the red dot finder was still several degrees off of the target objects. Will try a shim under the edge of the LNT mount to see if I can pull it in. Still waiting for another try of my "new" ETX-125PE after returning it for the third time to Meade's hospital in Mexico since receiving it late in 2008.

John

(Post Laureate)

03/12/09 02:27 PM

Re: ETX Problem - help required please

Glad to see it is working again-- but you should not be getting motor faults "all the time" ???????

Once in a while if the scope is very unbalanced --- but not again and again--- keep an eye on it-- may be something else???

Clear Skies!

(Galactic Hitch-Hiker)

03/12/09 03:02 PM

Re: ETX Problem - help required please

Quote:

Glad to see it is working again-- but you should not be getting motor faults "all the time" ???????

Once in a while if the scope is very unbalanced --- but not again and again--- keep an eye on it-- may be something else???

Cheers Joe,

Like you I was not impressed when I unpacked the scope and after doing a mock "Easy" alignment and slewing to an object the scope stopped dead in its tracks and I got the "motor drive failure (or was it drive motor failure") message. Tried again - same thing.

Phoned repair shop & told to do a "reset". Still got the same failure message. Not a happy bunny.

Still, I persevered and played around doing mock alignments again and I didn't get the fault message. If I get one more, I'll be writing a letter to the shop (and expecting them to ship it back to the shop, fix it and return it for free - as the shop is nearly 200 miles away).

Art

(Post Laureate)

03/12/09 03:42 PM

Re: ETX Problem - help required please

Yes-- that motor fault may be the reason behind WHY the board blew a fuse!!

(Galactic Hitch-Hiker)

03/12/09 03:45 PM

Re: ETX Problem - help required please

Quote:

Yes-- that motor fault may be the reason behind WHY the board blew a fuse!!

Good point.

So, would you advise not using the scope and getting the azimuth motor replaced?

If so, is this a simple DIY job? I really don't want to make a 400-mile round trip and the extra expense of getting a shop to do it if I can easily replace the motor.

Any idea of how to test the motor to see if it is suspect? I have a digital multi-meter.

Art

(Galactic Hitch-Hiker)

03/14/09 05:37 PM

[b]RA Drive Broken AGAIN![/b]

I spent yesterday (my day off) fitting two finder brackets to my Celestron NexStar 6SE.

The old Celestron RDF was to be fitted to my newly-repaired ETX105 as the Meade 6x25 RA finder is absolute PANTS. This I attempted today. Then I set out to align the newly-installed RDF ready for the first decent night's weather.

Sadly, it was not to be

I got not only the "Motor Unit Fault" message like I was getting on Wednesday, but the scope AGAIN wouldn't slew anti-clockwise (and no motor noise either). So I couldn't align the RDF except by manually moving the scope in RA anticlockwise and then slewing at a low rate closkwise (I was using the top of a mobile phone mast about 3 miles away).

Phoned the telescope shop. They are collecting it Monday by courier!

Grrrrrrr! NOT a happy bunny at all (to say the least)!

Art

Incidentally, Steve (the guy at the repair shop) said that the motor, gearbox and driver board had all been replaced during the repair.

(professor emeritus)

03/14/09 05:54 PM

Re: [b]RA Drive Broken AGAIN![/b]

Arthur:
Sorry to hear that the hospital has had to recall their patient. I hope the fault(s) get totally corrected this time.

John

(Galactic Hitch-Hiker)

03/14/09 06:04 PM

Re: [b]RA Drive Broken AGAIN![/b]

Quote:

Arthur:
Sorry to hear that the hospital has had to recall their patient. I hope the fault(s) get totally corrected this time.

John

Thanks John,

What I'm more concerned about is that I don't end up paying TWICE.

Also, it has to be said, that the scope ends up being fixed this time for good.

Art

(Post Laureate)

03/14/09 06:34 PM

Re: [b]RA Drive Broken AGAIN![/b]

Arthur-- hope they fix this the second time around-- bet the motor is causing the board to short out-- just guessing though--- ??????

(Galactic Hitch-Hiker)

03/14/09 07:04 PM

Re: RA Drive Broken AGAIN!

Hi Joe,

That's what I'd bet too - except that Steve, the guy at the repair shop, said that the motor, gearbox and driver board had all been replaced during the repair.

So I'm really puzzled as to what could be possibly causing this. The scope is powered by a Celestron 7Ah PowerTank (the output is 12.6V - I checked this with a multimeter this afternoon) and the scope is not "labouring" in any way when slewing in RA. Plus, it isn't against a hard-stop.

In fact, the scope is in "Home" position (ie Control Panel is facing due West, scope has been rotated anticlockwise until it reaches the stop, then rotated clockwise until the fork arm displaying "Meade" is above the Control Panel and the OTA is pointing due North). When the RA lock is released, the OTA freely rotates just over 1 3/4 revolutions to the other hard stop - ie just over 630 degrees.

I did a "mock" Easy alignment. The scope slewed to Capella OK, the second star chosen was Rigel (which, as you will know is slightly to the East of Capella). The Dec motors changed the altitude of the scope but the RA motor was silent. I then got the dreaded "Motor Unit Fault" message. A Reset didn't fix it, nor did a "Hard Reset" (ie power off/power on).

Any more ideas guys?

Art

(Galactic Hitch-Hiker)

03/19/09 04:07 PM

Re: RA Drive Broken AGAIN!

UPDATE:

Scope was collected Monday and returned home again today.

Did mock "Easy" alignment indoors - no problems. It also doesn't sound as if it is binding any more.

Repair note says "RA motor/gearbox assembly replaced. Worm tension checked on replacement unit and RA axis tension checked. Scope passed encoder test and 4 hour slew test" so hopefully (!) my baby is better.

Now all I need is some clear skies and to get rid of this wretched cold!

Art

(Galactic Hitch-Hiker)

05/27/09 04:04 PM

RA Drive Broken YET AGAIN!

FURTHER UPDATE:

Well, the saga continues.

Three weeks ago, whist some friends were visiting for the May Day Bank Holiday, I got the scope out to show them the Sun's disc as they had commented on a recent BBC news report of a "quiet sun" (they were impressed that you could use a telescope to look at the Sun). I tried a mock alignment and the RA drive broke again (but this time it was accompanied by the smell of cooking electrics, but no smoke)

Unable to work out why as a Celestron PowerTank was powering the scope at the time, so the voltage was just over 12V and the scope didn't appear to be binding at all.

The scope was duly returned to the Telescope Hospital and returned home this afternoon.
So far, it seems to work OK - or at least it has done continuously for over 3 minutes

I wonder whether it will work when I turn it on again

It is a real shame because OPTICALLY the ETX is fabulous.

Is this indicative that Meade's QC is appaling (sending out duff part after duff part) - or is there something fundamentally wrong with my scope mechanically (although I have been assured that this has been checked out)?

With the RA lock off, the axis is free to move both clockwise and anti-clockwise and the scope's hard stops are OK. Internally, there is no sign of loose connectors or frayed wires, so I'm puzzled.

As I said a few lines above, scope is currently WORKING - touches wood (head) for luck

Art

(Post Laureate)

05/27/09 06:32 PM

Re: RA Drive Broken YET AGAIN!

Well my OLD ETX90 is still working just fine on a Celestron powerpack-- at least for the last three years! Ha! (knock on wood-- where did I put that wood!)

Unless the shop has a bunch of bad motors? is this scope still under warranty-- if it is I would demand a replacement.

(Galactic Hitch-Hiker)

05/27/09 07:00 PM

Re: RA Drive Broken YET AGAIN!

Hi Joe

No, sadly, the scope is a s/hand unit purchased from a private individual. It is an ETX-105 EC and several years old, so out of warranty.

You may be correct I suppose in that the shop has had a batch of duff motors and/or electronics - hence my comment that I'm not impressed with Meade's QC if this is the case.

So far, I have only paid one repair charge including return shipping and all the subsequent to-and-fro shipping of the scope and repairs have been carried out by the shop at no further charge - to their credit.

I just hope this latest rapair is from a different batch of motors and/or electronics - otherwise "Yo-Yo" as I'm beginning to call my scope will be travelling South again!

Art

(Postmaster)

05/27/09 10:41 PM

Re: RA Drive Broken YET AGAIN!

Hmmm, I own quite a few Meade scopes and I've gotten great service from all of them. The smell of burnt electronics can never be good. The only thing I've feared is getting the polarity of my battery pack switched (which would be bad), but thankfully in 6 years of use it hasn't happened yet.

(Galactic Hitch-Hiker)

05/28/09 10:59 AM

Re: RA Drive Broken YET AGAIN!

Quote:

...The smell of burnt electronics can never be good.

No, it never is!

Quote:

The only thing I've feared is getting the polarity of my battery pack switched (which would be bad), but thankfully in 6 years of use it hasn't happened yet.

I've not done this to a scope but I have fried TWO electronic speed controllers (ESC's) when r/c car racing.

First one went in for repair & the company (who had a life-time warranty) replaced if for me 3 weeks later. My son and I went racing the day I got it back and I connected it up AGAIN reverse polarity. Talk about embarrased

They also replaced that one too!

After that I made sure that all the battery connectors were keyed so I couldn't make the same mistake for a third time!

Art

(super member)

05/28/09 04:27 PM

Re: RA Drive Broken YET AGAIN!

Quote:

FURTHER UPDATE:

Well, the saga continues.

Three weeks ago, whist some friends were visiting for the May Day Bank Holiday, I got the scope out to show them the Sun's disc as they had commented on a recent BBC news report of a "quiet sun" (they were impressed that you could use a telescope to look at the Sun). I tried a mock alignment and the RA drive broke again (but this time it was accompanied by the smell of cooking electrics, but no smoke)

Unable to work out why as a Celestron PowerTank was powering the scope at the time, so the voltage was just over 12V and the scope didn't appear to be binding at all.

The scope was duly returned to the Telescope Hospital and returned home this afternoon.
So far, it seems to work OK - or at least it has done continuously for over 3 minutes
I wonder whether it will work when I turn it on again

It is a real shame because OPTICALLY the ETX is fabulous.

Is this indicative that Meade's QC is appaling (sending out duff part after duff part) - or is there something fundamentally wrong with my scope mechanically (although I have been assured that this has been checked out)?

With the RA lock off, the axis is free to move both clockwise and anti-clockwise and the scope's hard stops are OK. Internally, there is no sign of loose connectors or frayed wires, so I'm puzzled.

As I said a few lines above, scope is currently WORKING - touches wood (head) for luck

Art

I don't feel Meade did a good job with the plastic parts. Say what you will, it made my decision on my next scope. It won't be a Meade. I hope you get things worked out.

(Galactic Hitch-Hiker)

05/28/09 04:35 PM

Re: RA Drive Broken YET AGAIN!

I'll keep you posted.

Either the shop has had a bad batch of motors/electronics (hopefully this repair is from a different batch)

or

there is a fundamental problem with the scope.

I'd like to think that the scope is properly repaired this time.

I used to refer to the scope as "baby" and the larger NexStar 6SE as "Junior". However, due to the scope being back to the shop for repair so often, I'm beginning to think of it as "YoYo"!

Art

(Galactic Hitch-Hiker)

06/02/09 05:31 PM

Re: RA Drive Broken YET AGAIN!

UPDATE:
Scope returned and it WORKS

I just hope that it works the next time I turn it on.

It has this nasty habit of breaking when I turn it on again!

Here's hoping

Used it to take a picture of 'ol Luna on Friday evening.

A bit of sharpening & brightness adjustment in Photoshop.

Art

(Post Laureate)

06/02/09 09:11 PM

Re: RA Drive Broken YET AGAIN!

Nice shot of the moon--- keep us posted on the scope--

Clear Skies!

(scholastic sledgehammer)

06/03/09 01:05 PM

Re: RA Drive Broken YET AGAIN!

Got my fingers crossed too. I can't believe the problems you've had with that scope. I hope it never gives you any more problems.
----
Dave

(Galactic Hitch-Hiker)

06/03/09 04:14 PM

Re: RA Drive Broken YET AGAIN!

Cheers David. Don't know whether there is something fundamentally wrong with the scope (I did purchase it s/hand after all) or I've just had a duff batch of circuit boards/motors fitted (it DOES happen).

Sincerely hope that it is fixed. As I'm powering the scope with a 12V PowerTank, I can't see that I'm doing anything wrong!

Joe, I'll keep you posted.

I'm still waiting for the Sun to develop some spots. I have a solar filter for the ETX but not for my 6SE. Then I'll do some AP (or should that be SP for Solar Photography?) on it. Last time I photographed the Sun, it looked like a ping-pong ball!

Art

(professor emeritus)

06/03/09 06:11 PM

Re: RA Drive Broken YET AGAIN!

Art:

Great photo of the moon. I'm glad you got the scope into good shape!! I also have and use the 7A. Power Tank with my ETX-125PE and like it very much.

I had a lot of problems with the finder and think I finally have the problems under control. Still waiting (for over a month) to get clear skies to get out and do a RESET, Train Motors, Drives, and Sensor cals so I can really find out how accurately the system points.

My main interest in this scope is to support "outreach" star party programs for neighbors in my community and familiarize them with the night sky and some of the wonders they can see even with a small scope.

John

(Galactic Hitch-Hiker)

06/03/09 06:51 PM

Re: RA Drive Broken YET AGAIN!

Thanks John

Still going through the AP learning-curve.

The shot was a single exposure: ISO 200, 1/80th sec (if I remember correctly).

I applied an unsharp mask in Photoshop and altered the brightness level slightly until it looked "right" to my eye.

Would love to try stacking (I have a copy of Registax 5 and Registax 4) but haven't really played with either prog.

I also have a webcam (Philips SPC900 which, as yet, hasn't even be connected to the computer - so more fun to come I'm sure).

Art

(scholastic sledgehammer)

06/04/09 02:48 PM

Re: RA Drive Broken YET AGAIN!

Quote:

Last time I photographed the Sun, it looked like a ping-pong ball!

Art

A very nice Ping Pong ball it has to be said.

Peter.

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