5 replies to this topic

[Oakland Paul]

First Post, so please redirect if needed.

Finally got aligned, mostly... got within a degree I'm guessing of targets. A good start for me... I touched up the aim and sidereal tracking gave me a steady Jupiter viewing then the moon, back and forth... 

 

UNTIL. The moon (from the Solar System list) was stuck in the display and none of the buttons responded. no esc, no slewing no enter....

 

So I turned the scope off and did some by hand steering but soon dis-assembled for the night...

 

Once inside, I power cycled the SynScan AZ to see if it needed a reboot. And while initializing...the Alt hub drove past zero and down into the cross piece. No scope in the mount to stop it so it went way past the horizon and made an ugly noise. I killed the power and headed for Cloudy Nights...

 

Am I hosed?

 

What do I do?

Edited by Oakland Paul, 06 February 2025 - 01:50 AM.

[havasman]

Hi Oakland Paul & welcome to the forums!

 

I messaged the moderators asking them to move your post to the reflectors forum where it should get more attention from owners experienced with SynScan than you will find here in the DIY forums. No problems with where you put it but more Dob owners will see a reflectors post.

 

I am unfamiliar with SynScan and can only suggest you might check the alt encoders to see that they are secure and properly gapped from the readers. And while you're in the area, check that the scope has not shifted in the base and that the wiring harness is properly and securely attached. Those are general checks when this sort of craziness happens.

 

You'll probably be OK. The accumulated experience here can be very helpful.

[Sean Cunneen]

Moving to reflectors for a better fit...  Also, try searching for "SynScan" in that forum, lots of info in there...  Might be cold related more than anything.

 

Sean

[Oakland Paul]

Thanks for the move to Reflectors (I'm digging through the SynScan posts now

More info:
Before I turned off the mount (while the display was stuck on the moon and the buttons stopped responding) the tracking started to dive... before I understood what was going wrong... We repeatedly hand slewUP against the drive to keep the moon in the eyepiece... and wondered why the scope was constantly fighting us.

 

Also:

I plugged in the handset minus the mount and it seems to be feeling fine... So it seems the alt hub is the location of the trouble. Seems.

 

Thanks in advance.

 

-Paul

[smiller]

Hi Paul,

 

These telescopes have slip clutches so in theory if the motor hits some obstruction it should just slip.  However I’m most familiar with the telescopes fully assembled and not just the base running on its own.
 

I would reassemble it and just see if it seems to operate. Is it still under warranty?

 

I use my scope for Astro photography at night and one time the telescope tried slewing 360 in the opposite direction and hit an obstacle, and for a fair amount of time (many minutes) it was just slewing and slewing (Az direction) against an obstacle and slipping.  It didn’t seem to damage it due to the slip clutch.  It can make an ugly sound though.

 

Another thing that can happen, if your slip clutch is tight and the worm gear interface is loose, is that the gear that interfaces with the worm gear can jump over the worm gear and I’ll make a hopping/ jumping sound. This can damage the gears if you allow it to happen a fair bit but if it just happens a little bit and just a few times it’s probably OK too. I’ve had this happen where my slip clutch was too tight and my worm gear interface was too loose and when I manually slewed it, it would skip.  

 

So there is a good chance that one of these is what happened to you and it’s all ok.

Edited by smiller, 08 February 2025 - 10:26 AM.

[Oakland Paul]

Hey Soyuz

I think your analysis is on the money. The force required to move the hubs is pretty great, so the alt drive is hard to move without the telescope as a lever. and when the hub is aimed down so far (and in a direction that prevents putting the scope back in!)... I was stumped for a moment.Then I thought, "Plug it in and see how it is without the hand set." It was fine. It just turns on and sits there... so it was not going to grind itself up... I turned it off and hooked up the handset and again, it behaved normally!... so I  used the up button and drove it to a better scope mounting position and everything seemed back to normal.

 

Normal enough to go and get a great night of Sidewalk astronomy, with Jupiter viewing (Transit of Europa's Shadow across the Great Red Spot!) and then a peek at the Orion Nebula.
 

Thanks also for the description of what is happening under the covers and the consequences of different fail modes. That will help me in the future, no doubt.

I'm calling it "case: closed" and back to observing between atmospheric rivers.