118 replies to this topic

[andylsun]

So I picked

 

 

up yesterday kindly from another CNer.

It comes with the accessories that are listed in the catalogue

 

 

and a motor drive unit that is clearly home made

 

Edited by andylsun, 06 September 2024 - 02:16 PM.

[andylsun]

The catalogue is here

 

https://wiki.telesco...985_Catalog.pdf

 

and it does appear to be close to the one listed on page 8 (Model 55715). Mine is f6.

 

Except mine is Blue. I can't find another picture of a blue one online.

Attached Thumbnails

• 

Edited by andylsun, 06 September 2024 - 02:13 PM.

[andylsun]

This restoration will probably be a flurry of posts followed by gaps. I'm not sure of the timeframe other than it'll be nice to have it up and running in the next few months.

 

Taking a detailed look at the motor drive controller show a few things.

 

 

It's home made, and the output seems to be ~9V AC to the motors in the mount. So it looks like we aren't deal with 120V AC motors in the mount.

 

I won't be plugging this hand controller into the mains 120V AC. For a start, the AC power cable is speaker wire, and there's a resistor pack floating in space in the middle of the unit. Once I get to look at the motors themselves I'll have an idea how to proceed with the motion elements. Either build a controller board for ~12V AC motors, or replace the motors with stepper motors.

 

The DEC axis has a tangent arm, and I've not removed the mount from the car yet.

 

This will be a light restoration. I don't intend to repaint or respray anything unless it's required. I like to let a item show it's age and not be factory fresh. I'm in awe of people who do go that route and make something look the same as it did the day it rolled off the factory floor, but that's not my style and certainly not within my capabilities.

Edited by andylsun, 06 September 2024 - 02:20 PM.

[andylsun]

The mirror is dirty for sure. Once I get to drop it out of the tube I can lightly clean it and see how it looks.

 

There's a second mirror (coated and with a centre spot) and secondary in another box. It's believed the original mirror is still in the tube. Will see what marks I can find on it when it's removed.

[andylsun]

The DEC motor is 115V 

 

the RA motor box has a AC power cord.

 

so the home made thing may be optional? Not required but allows change in sidereal rate? The RA box defaults to a fixed speed but can take external timing pulses? That’s my guess so far.

 

there’s a 1/4 jack socket on the RA motor box for this.

 

 

Attached Thumbnails

• 
• 

[andylsun]

RA is hurst motor.

 

I see what is going on with the home made box. The power switch on the RA motor mount is 3 position.

one off, one on but running from the RA AC feed.

Top position brings in the 1/4 jack connection from the home made box.

 

everything looks clean but I have not powered anything on yet.

 

DEC motor connects to the RA box and a two button hand controller.

Attached Thumbnails

• 
• 
• 

[deSitter]

Yes bidirectional synchronous motors. The home made box is I would think an inverter to be operated from a car battery. Set up for guiding. All this stuff looks very well made.

 

-drl

[andylsun]

The home made box also has an AC input and a dial for adjustment of the 555 timer inside. I wonder if it slows down the motor slightly. Sidereal is faster than lunar and solar rate? Perhaps it’s only needed for those slower rates.

 

yes the home made box has 12v input but it’s more than that I think. All very interesting.

[andylsun]

I was quite relieved to see it is simpler in the RA box than some of the Cave astrola dual motor setups I’ve found pictures online. Those have a lot going on.

[deSitter]

The home made box also has an AC input and a dial for adjustment of the 555 timer inside. I wonder if it slows down the motor slightly. Sidereal is faster than lunar and solar rate? Perhaps it’s only needed for those slower rates.

 

yes the home made box has 12v input but it’s more than that I think. All very interesting.

The speed of the motor depends on the input frequency, and the direction depends on which of the leads is activated. These inverters work by outputting a slightly different frequency to change the speed. Probably the DEC motor is just a fixed speed small enough for guiding operations.

 

-drl

Edited by deSitter, 06 September 2024 - 07:57 PM.

[andylsun]

Next steps I think will be to detach the motors and power up and see if they turn.

[andylsun]

I disengaged the RA motor from the gear wheel and powered on the mount.

 

RA motor spins well, uses 7W of power and isn’t getting too hot.

 

and the neon bulb still works!

will let it run for a few hours.

 

Attached Thumbnails

• 
• 

[andylsun]

Handbox has broken push button. This handbox controls the motor on the DEC tangent arm.

Attached Thumbnails

• 
• 

[andylsun]

DEC axis locking [collar?] bolt has some damaged threads.

 

bit of nylon rod came out with it.

 

The centre hand wheel to lock the DEC axis is missing.

 

 

Attached Thumbnails

• 
• 

[deSitter]

DEC axis locking [collar?] bolt has some damaged threads.

 

bit of nylon rod came out with it.

 

The centre hand wheel to lock the DEC axis is missing.

I assume that is some sort of centering device to stabilize the axis (the set screw with nylon insert).

 

-drl

[glittledale]

are you sure that knob is missing?  i thought it was sitting by the side of the mount.  i'll check to see if it's back at school if you don't find it.  

 

i think we cut a small nylon slug for that one last year.  it's not original.  

[andylsun]

are you sure that knob is missing?  i thought it was sitting by the side of the mount.  i'll check to see if it's back at school if you don't find it.  

 

i think we cut a small nylon slug for that one last year.  it's not original.  

Thanks! Let me check the car it may be rattling around there.

 

there was no knob pictured on the DEC axis in your original classified picture. It just had the hex headed bolt.

 

the hex head bolt does seem undersized for that threaded hole in the casting.

Edited by andylsun, 07 September 2024 - 03:35 PM.

[deSitter]

Thanks! Let me check the car it may be rattling around there.

 

there was no knob pictured on the DEC axis in your original classified picture. It just had the hex headed bolt.

 

the hex head bolt does seem undersized for that threaded hole in the casting.

That's what happened - that was put in there to act like a sort of clutch.

 

-drl

[andylsun]

Found the missing part. In the cup holder in the third row of my car!

 

RA motor has been running most of the day really well. 
 

next step will either be repair the hand controller so I can exercise the DEC motor or try the RA worm.

 

the worm does look very dry but it’s also brass or bronze? Any recommendations on lubrication? Is it designed to run drier compared to aluminum or steel worms?

Edited by andylsun, 07 September 2024 - 05:48 PM.

[andylsun]

Looking at the Cave Astrola recommendations for lubrication, sewing machine oil on the sintered bronze worm screw bushings, and grease on the worm itself seems to be the norm. So Superlube it is.

 

I’ve rebuilt 1970s Thorens turntables so bushings and AC motors are all familiar.

Edited by andylsun, 07 September 2024 - 06:35 PM.

[Kasmos]

The catalogue is here

 

https://wiki.telesco...985_Catalog.pdf

 

and it does appear to be close to the one listed on page 8 (Model 55715). Mine is f6.

 

Except mine is Blue. I can't find another picture of a blue one online.

I saw this staring at me in Sky &Telescope the day before you posted it in that other thread.

I thought you'd dig it!   

[andylsun]

**** that’s awesome. Which date of magazine?

tryimg to get a rough idea what vintage mine is. No stickers inside the RA motor housing.

 

I’m also wondering why the Parks has the RA lock but the Cave mounts do not. What benefit was the RA lock?

Edited by andylsun, 07 September 2024 - 08:25 PM.

[Kasmos]

**** that’s awesome. Which date of magazine?

tryimg to get a rough idea what vintage mine is. No stickers inside the RA motor housing.

 

I’m also wondering why the Parks has the RA lock but the Cave mounts do not. What benefit was the RA lock?

Several issues in 1991 had ads for them.

Here's one from Feb that year

[andylsun]

Several issues in 1991 had ads for them.

Here's one from Feb that year

Parks-Ad-2-91.jpg

So 90s. That’s newer than I expected, and may be newer than my LX6 Premium.

 

oh that’s interesting. 12V motors and spring loaded worms. Ok, mine is before that, it has the old style fixed worm mesh and 120V motors.

 

i wonder when they switched.

Edited by andylsun, 07 September 2024 - 08:34 PM.

[Kasmos]

I'm sort of in the process of rebuilding my S&T collection and  happened to notice them in some '91 issues I just recieved. They stood out since they were in color and most Parks ads I remembered were black and white. I'll have to see if the same scope is in the 1990 and 1989 issues.