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Tombstone Sky
One-Eyed Jack
Reged: 12/18/06
Posts: 1708
Loc: Tombstone Arizona
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First, a few weeks ago, I put the LX90 into Auto Align without tightening the AZ clutch. It started making a metal-on-metal racket, and I immediately turned it off. I tightened the clutch and continued.
Now, occassionally - but generally in the same orientation and moving the same direction at the same speed - I again get this sound. It's brief, but it's there.
First - is this a real problem? Meaning, can I expect it to get worse if I do nothing?
Second - Any idea what's causing this? Or more importantly, is there anything I can do to fix this?
Although the scope is under Sky Assure, I'm hesitant to call Meade until I have as much information as possible from other sources.
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MJ "Morg" Staley
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M5 Dark-Site Observatory
Meade 12" f/10 LX90GPS "River"
WO 2" Dielectric Diagonal
Meade SP 5000 full set, 24mm Meade 5000 UWA,
BO/TMB Planetary 8, 9mm, Nagler 13mmT6
Meade 505/USB/ASU/SNP6
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brianb11213
Carpal Tunnel
Reged: 02/25/09
Posts: 2099
Loc: 55.215N 6.554W
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If it's happening in the same direction it sounds like worm gear damage. However I don't see how running the motors with the clutch loose might cause that, surely the motor should have driven the worm gear round without moving the scope?
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Tombstone Sky
One-Eyed Jack
Reged: 12/18/06
Posts: 1708
Loc: Tombstone Arizona
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One thing I could try - if anyone thinks it'll do any good - is change the initial position and see if the sound moves to another part of the 'compass'.
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MJ "Morg" Staley
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M5 Dark-Site Observatory
Meade 12" f/10 LX90GPS "River"
WO 2" Dielectric Diagonal
Meade SP 5000 full set, 24mm Meade 5000 UWA,
BO/TMB Planetary 8, 9mm, Nagler 13mmT6
Meade 505/USB/ASU/SNP6
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obieone
member
Reged: 05/15/06
Posts: 27
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I've read of a few people who have had problems with the RA bolt with the LX90's, evidently when tightening down it doesn't fully clamp and lock the RA and slips because the plastic knob on the top rubs on the casing, Could this possibly be the cause? i mean the plastic knob rubbing causing the screech.
Jeff.
Edited by obieone (09/30/09 08:52 AM)
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Tombstone Sky
One-Eyed Jack
Reged: 12/18/06
Posts: 1708
Loc: Tombstone Arizona
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Quote:
I've read of a few people who have had problems with the RA bolt with the LX90's, evidently when tightening down it doesn't fully clamp and lock the RA and slips because the plastic knob on the top rubs on the casing, Could this possibly be the cause? i mean the plastic knob rubbing causing the screech.
Jeff.
I'll look at that when I run some more tests. Maybe today, tho I don't like exposing the scope to direct AZ sun.
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MJ "Morg" Staley
--------------------
M5 Dark-Site Observatory
Meade 12" f/10 LX90GPS "River"
WO 2" Dielectric Diagonal
Meade SP 5000 full set, 24mm Meade 5000 UWA,
BO/TMB Planetary 8, 9mm, Nagler 13mmT6
Meade 505/USB/ASU/SNP6
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obieone
member
Reged: 05/15/06
Posts: 27
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If it is the problem you maybe able to tell buy looking for rub marks on the casing under the RA bolt, a cure that has been successful is by placing a plastic/nylon washer in the recess under the bolt.
Think i read about this in the LX90 forum.
Hope this helps.
Jeff.
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Tombstone Sky
One-Eyed Jack
Reged: 12/18/06
Posts: 1708
Loc: Tombstone Arizona
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Well, I don't have a manual here that tells me how to field-strip this thing. I have no idea what an RA bolt is, or how to find it, let alone inspect it.
I'm going to start running some tests soon, to see if we can narrow down the scope of the issue.
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MJ "Morg" Staley
--------------------
M5 Dark-Site Observatory
Meade 12" f/10 LX90GPS "River"
WO 2" Dielectric Diagonal
Meade SP 5000 full set, 24mm Meade 5000 UWA,
BO/TMB Planetary 8, 9mm, Nagler 13mmT6
Meade 505/USB/ASU/SNP6
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Tombstone Sky
One-Eyed Jack
Reged: 12/18/06
Posts: 1708
Loc: Tombstone Arizona
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Ok, I've done some testing, and here's what's happening. With the scope pointed N, I slew the scope CW to S, no problem, but when I slew the scope CCW back to N, the screech is at approximately the SE point. HOWEVER this only happens with slew speed 9. On 8, not a peep.
This happens whether the OTA is vertical or horizontal.
But here's what's curious. I loosened the Az clutch and rotated the scope 90d CCW (E). I expected the problem point to also change 90d from SE to NE, but that's not what happened. The problem remained at SE. [Next sentence edited] So, whatever the problem is, it's at the SE location of something oriented to the tripod, not the scope, i.e. some fixed spot. And only CCW slew.
Any ideas?
Edited by Tombstone Sky (09/30/09 04:51 PM)
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obieone
member
Reged: 05/15/06
Posts: 27
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You may already know about 'Jans LX90 Pages' but just in case here's a link to it, it has loads of info on LX90's
http://jan.eaglecreekobservatory.org/
Jeff.
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Tombstone Sky
One-Eyed Jack
Reged: 12/18/06
Posts: 1708
Loc: Tombstone Arizona
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Well, I decided to play it safe and call Meade rather than risk a "fix in the field" option. The CS rep told me to try "Calibrate Motors" and see if that could chase the problem away. It didn't.
So - hate to do it - but it'll be going off to Meade. It's still under extended warranty, thank god. I still have my G&G 80mm anyway.
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MJ "Morg" Staley
--------------------
M5 Dark-Site Observatory
Meade 12" f/10 LX90GPS "River"
WO 2" Dielectric Diagonal
Meade SP 5000 full set, 24mm Meade 5000 UWA,
BO/TMB Planetary 8, 9mm, Nagler 13mmT6
Meade 505/USB/ASU/SNP6
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