Help with Intes MK66 focusing

[peterjl]

Hi,

Can anyone help with the focusing unit on my Intes MK66 which has a moving mirror SCT style but unlike the Intes Micro series, the focus knob can only push the mirror inwards, it cannot pull the mirror outwards. The outward return movement is dependent on a large spring around the central tube.

Turning the focus knob will push the mirror inwards okay (increase back focus) but when you want to bring the focus back in, you have to wait for the spring to push the whole mirror. In the last year this has got slower and slower. I have tried taking out the mirror assembly and try to free the grease but with no luck.

I do not seem to be able to disassemble the focusing unit and I don't want to force it in case I damage the mirror.

Has anyone come across this problem before perhaps on old Celestrons/Meades and knows how to free up the focusing.

Thanks

Peter

[peterjl]

Here is a picture if it helps.

[AndyH]

I can remember a similar problem with a Intes Micro M500. The person stripped/cleaned the mechanism, which cured the problem.

I can't for the life of remember where I saw that article tho.

Andy.

[barkis]

Is that the mirror in situ. there?. It looks a complicated arrangement, but only because there seems to be so much involved.

I assume the focus is full retracted in your picture.

Is the cap over the top of that large spring screwed on to the baffle? If it is, the unscrewing it should allow the mirror to be lifted off the baffle, and if so, have you done that to see what state the lubricant/ grease is in. If it is badly distributed, it could be the cause of the problem. Of course I'm only guessing as I can only go by the picture, never having seen this mechanism before.

Ron.

[peterjl]

This is not my mirror just a picture I found on the net but it is identical. I would say from the picture that the focus fairly retracted. The focus screw on the left can go in which will allow the mirror to also go in by leverage against the right hand stop. On the Intes Micro systems (different company), the focus knob is attached to the push/pull assembly so that it can both push and pull back the focusing arrangement. I cannot see how the Intes MK66 arrangement can be adapted in the same way.

The cap will not unscrew, I have tried really hard to get it to budge and as I say I do not want to break anything. Also the section below the spring will not unsrew, in fact I cannot get any part to unscrew.

The mirror and the centre section moves up and down against the spring and the fit is very tight, this is essential to keep good collimation which these Intes seem to be very good at.

Peter

[barkis]

There must be some information somewhere that explains how to disassemble this mechanism. Finding it is the problem of course.

I suppose a plea for information on other forums too might yield something. I can understand your reluctance to apply too much force to undo the top cap, but it must comee off somehow. Unless it depresses towards the mirror to reveal a snap ring of sorts.

There again, care has to be exercised when probing for clues.

Ron.

[dark star]

I have had my Intes MK 66 for a few weeks and so far have had no problems with focusing.

Hope you manage to fix the problem!

[dark star]

You could join the MakScopes users group on Yahoo and try asking on there, as someone has probably had the same problem.

[peterjl]

Thanks for the info about the Makscope group which I have just joined and I'm waiting for details back from the moderator.

I had done a lot of searching before to find information including forums and I am also surprised that I found very little. I guess this shows how good these Maks are that very few have problems. Most people really like their Intes. I certainly saw a big improvement over my old Vixen 102M on doubles and planets but I have had it for many years and I feel it is time to move on from photographic work perhaps onto a 10"/12" dob. I cannot sell it if it doesn't work properly.

Peter.

[Peter Drew]

I used to make Maksutovs professionally, I would suspect that breakdown in lubrication is the culprit. It's difficult to find a good grease compromise between load bearing capacity and freedom of movement, my best results were with a 50/50 mix of Rocol Kilopoise and Castrol LM grease. The top section probably is separate for assembly purposes but some manufacturers loctite components to reduce "tampering". If all else fails is might be possible to introduce some new lubricant between the coils of the spring and then carefully focus the system up and down. I'm not familiar with this scope and it's not easy to quite see the exact focusing action, however it does look as though the focusing effort is applied on the central axis which is good, it is the off-axis push/pull on SCT's that causes the annoying image shift.