Rollei 6x6 projector focus

Discussion in 'Accessories' started by john_ries, Dec 1, 2003.

  1. I've got a Rollei P66S medium format projector that is having a
    problem with the auto focus function.

    The auto focus works and so does the manual focus. The problem is that
    the auto focus drifts. When the first slide is focused manually the
    projector will then start to shift the focus, it won't remain in the
    sharp focus setting. It continues to drift the focus until it
    ultimately pushes the lens completely out of the projector body. Once
    in awhile it can be focused manually and the focus will not drift but
    as soon as a slide change is made the drifting starts again. The
    slides are mounted in Gepe anti-newton glass mounts.

    If anybody has any info that can help me out with this problem or
    knows someone or a place that can help please reply to this message.

    Thanks much..........John
  2. As the slide heats from the lamp its bending in the mount. In 35mm people buy special glass mounts and use flat field projection lenses for critical projecting.
  3. Mike........

    That is not the problem, the slides are mounted in Gepe glass mounts. There is some sort of problem with the autofocus mechanism itself. There are two electric eyes that are mounted in a plastic carrier that apparently slide on two metal rails and there is a sliding mechanism off to the side of that assembly that seems tight to me and doesn't move easily (it seems that way to me at least). Perhaps someone else has one of these rolleis and can tell me how much free movement should exist in these components or give me other tips.
  4. I made a whole web page about an auto focus problem on the P66.
    Check it out at:
  5. I have the same problem. I see this is an old post but hopefully I can get help. The link above is now dead. I have replaced the capacitors on the board but that wasn't the issue.
  6. Yes, hoping someone in 2019 still has the knowledge to help me fix the AF system. I got excited when I saw I had a reply. :-(
  7. Possible solution: Snip the wires to the AF motor and manually focus?

    Otherwise you'll have to check every function of the circuit. Does the AF sensor work? Dirty or broken? Is the comparator detecting AF lock? Is the motor controller switching properly? Etc, etc.
  8. No need to snip the wires. You can either tape the sensors with black electrical tape or do as I did and turn the sensor adjuster. It’s accessible via a hole in the bottom of the projector cover. This is to fine tune the AF, but since mine can’t be fine tuned, I just have it turned to the point of non movement. I have the service manual that explains the circuit but haven’t been able to identify all the components. I’m not used to working with circuit boards so it’s going to take some time to trace the AF circuit. I was hoping to see what others had to do to fix it. I have seen numerous posts saying the lens will not stop during AF and gets pushed out but no one mentions how to fix it. Mine is doing the same. For the heck of it I replaced all the capacitors. I only know how to check resistors and checked several while changing the caps. I’ll check the few remaining and try and trace the circuit.
  9. Is there a link to the service manual online?
    If so, I'll run an eyeball over the circuit and see if I can spot anything likely to cause the AF motor to overrun. or maybe there's a component that's known to wear out or become unreliable. Opto-couplers for example; nasty little things that go wrong at the drop of a hat!
  10. Thanks for the manual. There are a few non-standard symbols used in the CCT diagram, so it'll take a more thorough look to get my head round the workings of the AF module. However, I notice that two of the capacitors used are marked 'bipolar' - i.e. non-polarised. They're 10 microFarad in value and won't be easy or cheap to replace if needed. So I hope you haven't replaced them with standard polarised electrolytic types already.

    The manual focus appears to be 'fly by wire' where a two-way biased switch operates the focus motor. If this is correct and manual focus is working OK, then the motor driver must be functioning correctly and the fault is (probably) limited to the AF comparator. Have you checked the AF filament bulb is clean and in good condition? It needs to overcome the brightness of the projection lamp to function properly. Also check that the AF sensor module is free of dust that might obscure part of the split photo-sensor. Check the lenses on the AF lamp and sensor modules are clean and dust-free.

    There's an adjustment for AF positioning, a variable 'pot' - R103, which might have drifted out of adjustment, or developed a dirty track.

    I'll get back with a few more suggestions once I've fully got to grips with the circuitry.
  11. Hi Joe,

    I have replaced the C102 and C103 caps in question with these 106BPA050M Illinois Capacitor / CDE | Mouser they are bipolar but not sure about their specs for this application. They were less than $1 each.

    Yes Manual focus works well. The AF lamp is ever so slightly loose. Seems like the glue is a bit soft and yellowed. It's illuminated so I'm assuming it's still ok. I think I will remove it and clean the old glue off and re install. What type of glue shall I use? The unit arrived extremely clean inside however I have thoughtfully cleaned everything more including the two AF sensors. I'm not sure were the AF lamp lens is though. Maybe I have to remove the lamp to see it?

    I did locate the variable resistor for the AF sensitivity. I believe it's the P103, there is a regular resistor R103 as well. The P103 is accessible through the bottom cover. I have played with that and am using it now to prevent the lens from being pushed out the front. After I replaced the caps I tried to re adjust it. With all the covers off I put a glass slide in place and adjusted the P103 just untill the lens creep stopped. After that I manually focused the slide then reached in and pushed it a bit forward. This activated the AF motor but it would not stop. When trying to push the slide the other way the AF system would not activate. So it seems like one half of the system is not working.

    Thanks for your help, it's greatly appreciated!
  12. They should be OK. I was just worried you'd replaced them with standard polarised electrolytics, and that wouldn't have been good.
    Yes. P103 is the variable resistor.
    The wobbly AF lamp-holder doesn't sound good, and it might be advisable to fit a new bulb. Filament lamps get dim with age, and from the description in the manual, it sounds as if the brightness is quite critical. It looks as if there's a lens fitted to the AF lamp housing, but I can only go by what's apparent in the manual.
    No idea on that. It'll obviously have to be something heat-resistant. Maybe an epoxy type? Depends if you ever want to remove the thing again.
    Could be the related driver transistor, but I'm more inclined to suspect the AF sensor module. If you can get inside the housing, it'll definitely be worth gently cleaning it before looking for a replacement or digging further for the fault.
  13. Sounds good I’ll see if I can source a new lamp and remove the AF assembly to inspect closer. I’ll keep you posted.
  14. I removed the AF assembly for cleaning and inspection. The assembly has two lenses. One tied to the lamp the other the photocell. I first removed the photocell for cleaning. Between the photo cell and the AF lens, there is an infrared filter. This thin mylar filter was black. it should pass visible light, so there is the red flag. I put the filter against a fluorescent lamp and not a ray of visible light came through. I decided to put it back together without the filter and wallah! AF works!!!

    The question is should I source a new filter? At the lamp setting I use, there is not much heat at the negative. I have measure it a t 84 degrees. Also I wonder what made the filter go opaque. I'm thinking this is the reason so many have non op AF systems.




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