Focuser problem.

[woodmeister]

I have a problem with my focuser where the wheels on the focuser are very loose and do not shift the focuser up and down to gain focus. They just spin round and do nothing. The whole bar that the wheels sit on is very lose and wobbles slightly.

I can crab the focuser tube myself and pull it up and down without any resistance.

Any ideas on how to fix as I am mechanically challenged or will I need to replace my focuser? Out of curiosity does anybody know the drawtube travel on the skywatcher skyliner 200p focuser? Cheers.

[ronin]

Not sure if this is any good?

http://polluxchung.com/gso_crayford_fix/index.html

They are all similar so maybe consider it as a source of information.

It will be a case of taking it carefully apart, cleaning it up and reassembling.

Very likely that the wheels have lost contact and/or the grease has spread to the wheels/friction plate, so loss of grip.

[Moonshane]

Sounds like you need to adjust the tensioning grub screw. Although yours is a different focuser it should be the big central one arrowed in this pic http://stargazerslounge.com/uploads/monthly_07_2010/post-12764-133877465277.jpg

[Herbig]

I wouldn't take it apart until you have tried adjusting it.

[Moonshane]

Agreed

[woodmeister]

Cheers. I feel a bit dumb since I did not check it in the first place. But at the same time I am surprised it has slackened off.

I bet somebody slackened it off while I was not there or my 23mm luminos somehow slackened it off. Thank you for the quick responses I can observe again now  

[Moonshane]

sometimes the cold makes the metal shrink so much that they slacken off.

[lensman57]

I have a problem with my focuser where the wheels on the focuser are very loose and do not shift the focuser up and down to gain focus. They just spin round and do nothing. The whole bar that the wheels sit on is very lose and wobbles slightly.

I can crab the focuser tube myself and pull it up and down without any resistance.

Any ideas on how to fix as I am mechanically challenged or will I need to replace my focuser? Out of curiosity does anybody know the drawtube travel on the skywatcher skyliner 200p focuser? Cheers.

I can tell you by the description you  have posted that you are talking about a Crayford . Provided that the top ball  bearings are in good shape then an adjustment of the tension screw at the bottom of the focuser should do it . If there is no tension screw then the Teflon bearing block needs to be raised to increase the pressure on the steel shaft. To do this, there are two small screws that hold the Teflon bearing and a central screw that puts pressure on the block. these two little screws must be loosened by a very small amount but equally and then the central screw tightened slightly to increase the pressure. Go very gently and in small steps as undue pressure can and will crack the casings of the top ball bearings.

A.G

[woodmeister]

Cheers. Fortunately all it took was tightening the bolt next to the locking screw to sort the problem