[Bobbyoutback]

Fully agree with what Wavy said !
A recent example of a GoTo mount that can't seem to find things .
I've asked a clever mate to try & find a fix .

He sent the following email today :


Following a partial disassembly I have discovered the fault lies in the drive mechanism to mount fastening devices - ie the scope plastic mounting structure (and Alt drive assembly) is not perpendicular with the AZ drive plate.
The attached image shows the lower cup attachment (metal cup that secures the whole assembly to the tripod) and a dark grey fibre washer.

This washer is the only thing holding the large drive gear to the assembly and also acts as a friction brake to stop overrun.

The larger assembly (main body that precesses) has 3 equi-distant white silicone pads (dots) that act as bearings on the outer surface of the lower cup attachment.

They decided to assist the bearing surfaces by smearing grease ( with the consistency of Yellow Box Honey) on the lands (bearing surfaces)of the lower cup - and subsequently turned it into a high drag surface area. Probably why low speed slew has a hard time moving. (DC motor variable speed and constant torque).

I am now going to remove the outer covers and examine the mountings for the Body to AZ assembly - more discoveries to come!

As a rough estimate and envisioning the 1-2mm deviation of the AZ base) I would give a few arc minutes of error!