Last updated: 31 October 2008
This page is for user comments and information specific to the Meade ETX-60AT, ETX-70AT, ETX-80AT-TC, and ETX-80BB. Additional information is available on the ETX-60AT & ETX-70AT Announcements page. Comments on accessories and feedback items appropriate to other ETX 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: ETX 80 will not rotate counterclockwise... Sent: Friday, October 31, 2008 19:11:19 From: firstname.lastname@example.org (email@example.com) Hope you can help. Purchased a ETX80 a few weeks ago for my Daughter. It was purchased from a person who purchased it new, but it sat in the box for 2 years. It was as near as I could tell, never out of the box (all the plastic still sealed). It has been working fine until tonight while slewing to the first alignment star, it motor faulted. I went through motor reset and started to re-calibrate the motors when I noticed that the left arrow on the 494 had no effect (it move clockwise and up and down just fine). (Powering off of 12V power pack rather than 6xAA, and the battery is freshly charged). Based on information on your site, I did check the 494's plug and socket but all looked fine and wiggling the plug in the socket had no effect on behavior. Based on the fact that the autostar reports motor unit failure if I hold left button down long enough, I don't think the problem is in the 494, but rather the driver chips for the motor. Seems kind of odd that it would turn in one direction but not the other though. So a couple of related questions on this problem: 1) Am I missing anything, any suggestions? 2) Do you know if anybody has a schematic for the ETX 60/70/80 controller boards? Thanks in advance, MikeMike here: First, I would suggest trying internal batteries. Probably won't change the situation but it might if there was not external power source problem (cable, etc). Second, with the horizontal axis unlocked, when you move the tube horizontally (slowly) can you feel any resistance? That would indicate some obstruction. If none of that helps, then you might want to read the articles "Repair ETX-60 Azimuth Problem" and "Repairing ETX-60 Azimuth Drive" on the Helpful Information: Telescope Tech Tips page. The ETX-80 may be similar enough to the ETX-60 that those might help.
Subject: ETX80 AZIMUTH TRACKING PROBLEM Sent: Sunday, October 19, 2008 23:28:45 From: Mike Terry (firstname.lastname@example.org) I have just aquired a two year old mint condition ETX 80 but am having trouble getting it to align. The Alt motors drive the scope very smoothly but the Az drives are sometimes a bit jerky at some points in the rotation. Is this usual or do I have a drive problem. Thanks for your great site. Best Regards Mike TerryMike here: There could be several reasons for the jerkiness. Have you done a CALIBRATE MOTOR and TRAIN DRIVES (on both axes)? If not, do those. Perhaps that will solve it. If you have done them and the problem is still there, it could be that the lubrication needs to be redistributed. Loosen the axis lock and slowly rotate the telescope around the horizontal axis by hand, going in both directions for a couple of complete turns. If that doesn't cure it, it could be that there is some physical damage on the locking mechanism or that a gear mount is loose or that a gear has one or more broken teeth.
Subject: ETX-80 Sent: Monday, October 13, 2008 17:23:54 From: John Pfeil (email@example.com) A friend of mine just bought a used Meade ETX-80. He tried to focus it and found that the focus did not work. He asked me to come over to look at it, and I found that the internal end of the focus knob is viewable and accessible via a square plastic cover that is secured with a small phillips head screw. After removing that, I found that a piece, or pieces are missing that connect the internal end of the focus knob to the long threaded metal rod that moves the primary lens back and forth in the tube. Is there a "exploded" diagram or something similar that would help me determine the missing part or parts? If so, I'll contact Meade to try to order what's missing. Not only could I use that for fixing the focuser, but I could take it all apart to clean the secondary mirror (there is grease on it, probably from when the mechanism came apart). Thank you. Regards, j.p.Mike here: While not specific to the ETX-80 (which may be slightly different), there is the article "ETX-70 Focus Knob Fix" on the Helpful Information: Telescope Tech Tips page.
Will do. You are kind to have answered. You must get a lot of folks like me needing help! Regards, j.p.
Subject: Re: ETX 80 jerks during tracking Sent: Wednesday, October 8, 2008 14:58:47 From: David Logan (firstname.lastname@example.org) First, a huge thanks for your help, and, for having such a great site! I was finally able to get out today, and did a calibrate motors. No problems. During train drives, I noticed a LOT of slop in azimuth. Plus, as experienced the other night, movements were jerky. So much so, that I had trouble stopping with my refrence point in the center of my view. After training, I was playing with the movements, and, there is a three to four second lag when changing directions before the scope starts moving. At higher slew speeds, the jerking isn't noticeable, but, it's definately still there at slow slew speeds. I also tried changing the Az percentages, with no difference in movements at all. One thing I've noticed, since getting the scope new, compared to my ETX 60, the azimuth axis of the 80 seems very tight, even when not locked down. Is it possible that it was set too tight from the factory, and, over a period of use, I've unknowingly been over tightening it, possibly damaging something? If so, is there a way to open this up, and, what do I look for. Or, should I try sending it back to Meade? Thanks again, DavidMike here: I don't have an ETX-80 to compare but if the axis is being (or has been) overtightened then some damage could have be done. That might cause jerkiness and hesitation in movement. If you open up the base you may or may not be able to see what's wrong. Might be best to contact Meade.
Subject: ETX 80 jerks during tracking Sent: Saturday, October 4, 2008 20:25:52 From: David Logan (email@example.com) I have an ETX 80 BB, purchased early this year, that has been trouble free, until now. I did the Autostar guided tour for a bit, then went to Jupiter to study it for a while. After about 5 minutes of tracking, it began to jerk (appeared to be in azimuth), with a barely audible popping noise. It still slews just fine, and, goto is still very accurate. I went ahead and wrapped up my session, fearing damage could occur if I continued. I am mechanically inclined, but, have never seen past the battery compartment in this scope. Any help would be greatly appreciated. Thanks, David L.Mike here: Couple of thoughts. If the problem is consistent regardless of direction then it could be a wire catching in the gears or a broken gear mount. But since the problem does not occur during slewing you might be able to rule that out. In which case try doing a CALIBRATE MOTOR and TRAIN DRIVES.
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