|This page is for user comments and information specific to the Meade DS, DSX, and some older telescope models. Accessories and Feedback items appropriate to the ETX models are posted on other pages as appropriate. 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: Re: DS-2102 mount slewing error Sent: Thursday, June 30, 2011 11:16:23 From: Saul Grijalva (firstname.lastname@example.org) Just to let you know. I sent the mount to mexicos Meade dealer customer support. Unfortunatly the mount was to old and there was no warranty and no mounts to replacement, the diagnosis, "general failure in the board". They offer me a new ds-2000 II Generation with a 30% off and I acepted. They sent me too another old ds-2000 mount to spare parts, it had a defect in the dec knob but I just ajust it and now the mount works apparently fine! So I have now 3 mounts!, my useless mount, the new ds-2000 gen II, and the old mount they sent me to spare parts but now working!. Regards, Sal.
Subject: re: Meade Autostar motors Sent: Sunday, June 12, 2011 08:55:51 From: richard seymour (email@example.com) Mike mis-spoke a little when he wrote: > There are no "smarts" in the telescope itself. There are smarts in the scope motor units. The Meade motors have a shaft encoder (a slotted disk) mounted on each motor, providing positional feedback. The motors and encoders are directly connected to circuit cards in the scope (or motor boxes) which have PIC (Programmable Intelligent Controllers) chips which convert messages from the Autostar ("move at such-and-such a speed") into PWM (pulse-width modulated) signals to the motors. The PIC chips also read the encoders and use their signals for full servo-controlled adjustments of the PWM signals to maintain the desired speeds. The PIC chips also send (upon request) integrated results from the encoder signals back to the Autostar so that the Autostar can tell how the scope is moving. The 4 wires you were seeing are the Autostar's I2C-like messaging bus (plus power and ground), not simple direct power for the motors. It's the in-scope PIC chip (and other parts) which provide the two-wire motor drive power. It's all explained in US Patent 6,304,376 which can be accessed via this site: http://www.pat2pdf.org/ have fun --dick
From: Jim Isbell, W5JAI (firstname.lastname@example.org) Thanks for the explanation. But all the smarts are in the motor housings and not in the pedestal if I understand correctly? Only wiring is in the plug patch panel at the bottom of the pedestal. All the rest is only two worm gear sets. Right? Jim Isbell
For the older DS models, "yes". The scope base only had a connector panel. Each motor unit had its own circuit card in the little black box. The newer ("one arm") DS models have the circuitry built into the arm. The ETX-90/105/125 have the circuitry built into the base (the Az card) and one arm of the fork (the Alt card). have fun --dick
Thanks. Jim Isbell
Subject: Meade Autostar motors Sent: Wednesday, June 8, 2011 20:33:05 From: Jim Isbell, W5JAI (email@example.com) I found your very informative page but amazingly enough it didn't answer my question. I just bought a DS-90 in a thrift shop for $10. It is in good shape except for the missing parts. The eyepiece I can find. But I cant find a source for the two (AZ/El) motors. I was wondering about replacing them with other motors but it seems there is also some electronics in the plastic boxes as there are four wires, not two as I had expected, for connection. So I assume I will have to find a pair of original motors for the mount. The Meade website does not list them for sale nor, for that mater, any repair parts. Can you suggest a reasonable course of action to motorize this mount considering that it is not an expensive system to begin with so must have an economical solution? Jim IsbellMike here: Try Telescope Warehouse (link on the Astronomy Links page). Alternatively, you can try a hobby shop. Meade usually does not sell parts.
Thanks, I found the website and they have GREAT prices. No motors listed, but I posted a note to them to see if they can furnish them. Meanwhile I have found a surplus motor with worm gear for $9 that I think will work and I think I can design the electronic switch to run the motor and reverse it. But if I can find originals it would be nice. I probably wont be using the Meade padle but will be writing the software to use my laptop as the controller. Jim IsbellMike here: Glad you found something that might work. If your software is only to turn on and off the motors through your switch, then you'll be OK. However, if you want to control the telescope using the AutoStar commands, then you need to actually have an AutoStar. There are no "smarts" in the telescope itself.
Yes, I discovered that. At first I thought there was some position "feedback" but I see now that there isn't. One advantage of starting over and just using the mount for the mechanicals is that I can build into the hardware and the software a feedback loop so that repositioning will be acurate , not just a guess based on the "calibration" of the motors. I will let you know if I do anything significant. Jim Isbell
Subject: RA motor drive Jurk Sent: Sunday, June 5, 2011 18:22:48 From: Arif Shaikh (firstname.lastname@example.org) I have DSX-125 and just noticed that when I move the scope in RA/Az, initial it gives big jurk and then start normal slew. This happen even if I select lowest speed. I am wondering what could be the problem. ThanksMike here: There can be many causes for this. First, do a CALIBRATE MOTOR and TRAIN DRIVES. If that doesn't solve it, unlock the axis and rotate the telescope back and forth full circle several times to redistribute the lubrication. If the problem persists, it could be a loose or broken gear or gear mount; you would have to open up the base to check on that.
I did calibrate,train the drive and rotated the telescope back and forth. But this did not help. I also rotated the scope full turn using autostar and found that during full rotation, at some stage it gives jerk to the scope so heavy that the entire tripod sacks. Now I thing there might be inside the gear which is causing all the problem. I want to open the azimuth assembly and checked your website, but could not find the clear instruction how to open it. Do you know where can I search for this instructions. Thanks for your help.Mike here: My ETX Site does not currently have any disassembly instructions for the DSX models. However, there are some similarities in the base so instructions for the ETX should be similar. Check the Helpful Information: Telescope Tech Tips page. If you want to document your disassembly of your DSX-125, I will be happy to include it on the ETX Site.
Subject: Re: DS-2102 mount slewing error Sent: Wednesday, June 1, 2011 15:23:35 From: Saul Grijalva (email@example.com) Just to let you know. I continued doing what you advice me but no results. I decided to buy a new mount but Mexico´s Meade dealer ask me why I needed a new mount so I tell him the problems with the mount and he ask me to send the mount and controler to the dealer and maybe they will reemplace with a new one, I hope!. Thank You!. Saúl Grijalva.
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