DS, DSX, OLDER MODELS FEEDBACK Last updated: 30 June 2011

Subject:	Re: DS-2102 mount slewing error
Sent:	Thursday, June 30, 2011 11:16:23
From:	Saul Grijalva (sgrijalva@yahoo.com)
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 (rseymour@wolfenet.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

And:

From:	Jim Isbell, W5JAI (jim.isbell@gmail.com)
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

And:

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

And:

Thanks.

Jim Isbell

Subject:	Meade Autostar motors
Sent:	Wednesday, June 8, 2011 20:33:05
From:	Jim Isbell, W5JAI (jim.isbell@gmail.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 Isbell

And:

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 Isbell

And:

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 (arifmshaikh@yahoo.com)
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.

Thanks

And:

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.

Subject:	Re: DS-2102 mount slewing error
Sent:	Wednesday, June 1, 2011 15:23:35
From:	Saul Grijalva (sgrijalva@yahoo.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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