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Re: [Losmandy_users] Persistant GM8 problem


Jan 19, 2002

 


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#8043 Jan 19, 2002

Dear friends,

I have a problem with the declination axis of my GM8.

When adjusting the worm gear backlash using the usual procedure

of pressing together the two loose bearing blocks and gently pushing

against the worm gear and tightening the screws again, I can easily

hand turn the worm, as fine as expected for an appropriately adjusted

backlash.

But, this is not constant with axis rotation: what happens is that

if now I manually rotate the axis at a different angle,

after the adjustment described above,

then I may end up with the worm no longer rotating freely by hand.

This is true even if the clutch knob is loose.

The problem is quite annoying, in fact the reason why I started

playing

with the backlash is that at particular positions of the declination

axis

the motor would not make it in moving the well balanced telescope

in either direction or both.

Furthermore, I noticed that the plane of the saddle plate is not

exactly perpendicular to the shaft that goes into the needle bearings.

The result is that the two discs that compress the nylon disc when

tightening

the clutch knob, are not parallel to each other and in fact I can see

a varying gap

between the worm gear disc and the saddle plate disc; this means that

the two discs touch in one point while there is a gap of ~0.4 mm 180

degrees

from there (I removed the nylon disc to perform a more accurate

measurement).

Rotating the shaft simply causes the contact point to rotate.

I do not know if the latter problem can be

in connection with the former one.

Has anybody ever had such problems and what is the solution to them ?

I bought the new mount from an Italian dealer a few months ago,

it has never undergone shocks of any sort, and the warranty is still

valid.

Thank you everybody.

Sandro



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#10852 Jul 7, 2002

Howdy.

Well, drive problem, actually, my G11 hasn't done this, yet.

Out observing last night, I found that the slew speed had

reset itself to the default (.3x) position without my

permission at least three times during a 3-hour run.

Why should this occur? Many thanks.



David Neal Minnick

Lake Elsinore, CA



"The meek shall inherit the gulag."



----------------------------

#10854 Jul 7, 2002

It might be a loose connection causing momentary power dropouts. If you are

using the supplied battery connector, that's a good place to begin your

check. On mine, one of the wires was simply wrapped around its terminal. As

time went on it loosened up and the power connection became increasingly

intermittent. I soldered it on and added some crude strain relief with some

electrical tape.



David Brodeur

> -----Original Message-----

> From: dmfoptics [mailto:DMFOPTICS@...]

> Sent: Sunday, July 07, 2002 8:19 PM

> To: Losmandy_users@yahoogroups.com

> Subject: [Losmandy_users] GM8 problem

>

>

> Howdy.

> Well, drive problem, actually, my G11 hasn't done this, yet.

> Out observing last night, I found that the slew speed had

> reset itself to the default (.3x) position without my

> permission at least three times during a 3-hour run.

> Why should this occur? Many thanks.

>

> David Neal Minnick

> Lake Elsinore, CA

>

> "The meek shall inherit the gulag."

>

>

>

> To unsubscribe from this group, send an email to:

> Losmandy_users-unsubscribe@egroups.com

>

>

>

> Your use of Yahoo! Groups is subject to docs.yahoo.com/info/terms/

>

>



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#41635 Feb 9 4:52 PM

.

I have a problem when I press the right RA button on the hand controller with slewing set to 16X nothing changes except it does continue to track at 0.3.

.

I pulled the board in the Digital Drive system and looked at both sides.. Some of the larger solder joints had some brown flux flow that I cleaned off. I examined everything with a magnifying glass and didn.t see anything that looked like a short to me, but I am not really experienced at that.. I don.t have a schematic but I got out a volt meter and traced a few lines with the ohms side checking for continuity.. I couldn.t really discover anything.

.

I will tell you what I see when pressing the buttons. With the counter weight to the north and the scope pointed towards the east wall. When I press the upper button the Dec gear coupling rotates clockwise and the laser goes down & right.. When I push the bottom button the Dec worm gear coupling rotates counter clock wise and the laser goes up & left.. When I push the left button the RA worm gear coupling goes counter clockwise and the laser goes down & left on the wall.. Now here is the problem. When I press the right button nothing appears to happen but I believe it just keeps tracking at 0.3 but that is really hard to see while looking at the worm gear coupling.. When I throw the reverse switch then while pressing the right button the RA worm gear coupling goes counter clockwise and the laser goes down & left on the wall at 16X.

.

I have tried switching motors and cords.

.

Any recommendations on who would be a good source to send the equipment to for fixing?

.

Jim

.











[Non-text portions of this message have been removed]







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#41665 Feb 11 2:55 PM

With the help of Tom Hilton I was able to get the problem fixed.. After describing the problem to Tom who never worked on a GM8 with no Gemini he was clever enough to figure out where the problem was and coached me on how to trace the problem down with a volt meter.

.

I followed his instructions and found a break in the blue wire (pin 6) in the hand controller cable.

.

My hand controller cable is a bit shorter now but everything works.

.

Thanks to Tom.

.

Jim Gibson

.



.

.



--- On Mon, 2/9/09, Jim Gibson jimgibson00@...> wrote:



From: Jim Gibson jimgibson00@...>

Subject: [Losmandy_users] Persistant GM8 problem

To: Losmandy_users@yahoogroups.com

Date: Monday, February 9, 2009, 5:52 PM



.

I have a problem when I press the right RA button on the hand controller with

slewing set to 16X nothing changes except it does continue to track at 0.3.

.

I pulled the board in the Digital Drive system and looked at both sides.. Some

of the larger solder joints had some brown flux flow that I cleaned off. I

examined everything with a magnifying glass and didn.t see anything that looked

like a short to me, but I am not really experienced at that.. I don.t have a

schematic but I got out a volt meter and traced a few lines with the ohms side

checking for continuity.. I couldn.t really discover anything.

.

I will tell you what I see when pressing the buttons. With the counter weight

to the north and the scope pointed towards the east wall. When I press the upper

button the Dec gear coupling rotates clockwise and the laser goes down &

right.. When I push the bottom button the Dec worm gear coupling rotates

counter clock wise and the laser goes up & left.. When I push the left

button the RA worm gear coupling goes counter clockwise and the laser goes down

& left on the wall.. Now here is the problem. When I press the right button

nothing appears to happen but I believe it just keeps tracking at 0.3 but that

is really hard to see while looking at the worm gear coupling.. When I throw

the reverse switch then while pressing the right button the RA worm gear

coupling goes counter clockwise and the laser goes down & left on the wall

at 16X.

.

I have tried switching motors and cords.

.

Any recommendations on who would be a good source to send the equipment to for

fixing?

.

Jim

.











[Non-text portions of this message have been removed]







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