Synscan misbehaving

[red1902]

Hi

I have been having some difficult calibrating my SkyWatcher Explorer 130P SynScan AZ GOTO scope that I recently purchased.

While I understand this is not uncommon, I feel I have followed all the instructions and read numerous help forums and believe I have avoided the usual pitfalls (Long/Lat, American dates etc).

Today I discovered the SHOW POSITION function, so bypassing all calibration settings and simply using that function I observed the following.

Simply using the UTILTY FUNC > SHOW POSITION, whenever I rotate the scope through approx 360 degrees, the function displays 524 degrees of rotation.

ie it thinks it has rotated further than it actually has. 360/524 suggests it is moving only 68% of the requested rotation. Rotation is smooth but the error is consistent all the way round, ie at 90 degrees it thinks it has rotated 131 degrees.

This explains why when using two star calibration, it never even gets close to the second star. I have to slew it round quite a distance to align it with the second star. Unnervingly, it always reports alignment successful!

It is pretty consistent - every time I try this it records 524 degrees of rotation when the mount has only moved 360 degrees.

I've tried the restore factory settings - no change.

Am I doing something stupid? do I have a faulty mount? or is there some calibration setting I have overlooked?

Thanks for your help