Dobsonian problem

[robindurant]

I have a SW Flexitube controlled by a Syn Trek Auto track.  The problem is although the Alt motor system is truning ( wheel spinning) when in tracking mode , the scope is not. I have adjusted the Clutch nut but this does not have an effect, the strange thing is that when I manually slew, the scope turn OK  at all 3 speeds but not when in a tracking mode . The Dec operation is OK. and I have set it up the Latitude correctly.

[brantuk]

Dobs don't have a Dec axis - it's gotta be alt and az. Are you sure the alt isn't moving the scope - it's hard to perceive visually cos it's so slow - have you checked it in daylight on a fixed object to see if it's tracking up/down, away from the object? Give it five or ten mins in tracking mode and you should see it drifting if it works - or staying still if it doesn't. Hth

[robindurant]

1 hour ago, brantuk said:

Dobs don't have a Dec axis - it's gotta be alt and az. Are you sure the alt isn't moving the scope - it's hard to perceive visually cos it's so slow - have you checked it in daylight on a fixed object to see if it's tracking up/down, away from the object? Give it five or ten mins in tracking mode and you should see it drifting if it works - or staying still if it doesn't. Hth

Hi, yes wrong terms, I setup the scope indoors with a marker facing South. I left it for 15 minutes, the Scope moved 1 " up alt and nothing to the right, az,  at all,  maybe I'm expecting too much. I will try it during the day on a distant object

[brantuk]

I remember my 12" flextube (when I had one) slowly started getting stiffer and stiffer in the azimuth and the motors started to sound like they were straining. I too tightened it up a bit but only made it worse cos there was a piece of polystyrene between the baseboard and bottom board providing "sticktion".

I ended up loosening it off and stripping the whole lot down to add a bit of lubrication to moving parts and retensioning a cog to get it going right again. There's a little drive cog on a sliding plate bolted up to the large az cog which can work loose. But if you're nervous about taking these things apart it may be as well to get an experienced friend to help (like I did). Hth

[robindurant]

Many thanks, I did strip it down the base and lubricate etc, maybe I need to look at it again in case I tightend up some bits too much, the thing is that when I dissengage Tracking and fast slew, it works fine, only on tracking is the problem, could it be a handset problem?

[brantuk]

Hmm.... yes that is a weird problem - if you've already stripped it down, and it only happens when tracking - then it would suggest a software/handset problem. It might be an idea to update the handset and motors encoders software - or if it's a recent purchase get in touch with the retailer to discuss first.

[robindurant]

13 hours ago, brantuk said:

Hmm.... yes that is a weird problem - if you've already stripped it down, and it only happens when tracking - then it would suggest a software/handset problem. It might be an idea to update the handset and motors encoders software - or if it's a recent purchase get in touch with the retailer to discuss first.

There isn't any firmware for the SkyTrek handsets , they are not upgradeable and also obsolete, however FLO are lending me a handset to try, great Company, I wish all were as helpful as them

[robindurant]

I have found the problem it was the clutch nut tension, both directions slew now, I assume that if the clutch is too tight or loose the wheel will turn without turning the scope, however another strange thing has occured now its slewing, it is slewing the wong direction in the AZ and befre you ask, I set it up facing North, the ALT is going in the right direction, Weird !