Topcon Super RE - Light Meter Help

Discussion in 'Classic Manual Cameras' started by stevenenglund, Dec 5, 2017.

  1. Steven, you have almost certainly already though about that, but anyway: before coming to the conclusion that the meter is broken, have you tried and carefully cleaned the contacts in the battery compartment?
     
  2. Pls ignore my message above, which makes no sense. And, I must apologise for having misled you in my answer as to whether the meter bar moves with no battery in the camera. Mr Shriver is of course correct - and yet, I could swear than when I did check it out after your question, it was frozen solid as in your drawing. Go figure...
     
    Last edited: Dec 12, 2017
  3. @bonsignore_ezio Not a problem! I have been told to try cleaning the contacts with vinegar, which I will try tonight after work. If it's still not working I will bring the camera to a local repair shop here in Portland, OR for a price estimate. I've been chatting with Jon Goodman and he along with Rick Oleson have agreed that the meter on this camera is really finicky. Which is odd because the rest of the camera is built so well! I guess that's what you get when you are the first camera with TTL metering in the 1960's =)
     
  4. Steven, cleaning the contacts (I use alcohol which unlike vinegar evaporates nearly completely) would do no harm, but the point rather is: Mr Shriver has stated that the meter bar should move reacting to changes in either aperture or speeds even with no battery, and I checked this and he is indeed correct (I don't know why at my fist test this did not happen, but never mind). If the meter bar in your camera doesn't move, this indicates that the problem is not in the electric part of the meter assembly, but rather in the mechanical connections. So, the problem will remain irrespective as to whether the battery compartment provides good contact or not.
     
  5. But the meter DOES move. As I mentioned, the black band appears near some very low light settings. For example, ASA 100 and 1 to 2". Therefor I know the chains are still linked.

    Which means it's likely either a bad wire connection or a stuck needle.
     
  6. Update: I've brought the camera to a repair shop. It had the Zeiss lens attached, they told me that they cannot test the functions of the light meter without a Topcon RE lens. That seems puzzling to me, since the light meter should be reacting regardless of which, if any, lens is attached! Can anyone shed any light on that situation? Specifically those of you who have Topcon Super REs or Super Ds...
     
  7. I have a Zeiss Jena Pancolar "double zebra" very similar to your Tessar, and I put it on my Super D and then just to be sure tested it again on my RE-2. The results are:

    - The meter would not react to changes in aperture in the TTL mode, because there is no linkage to tell it what aperture you have selected.

    - The meter would however react, and provide credible results to changes in speed - with the aperture "fixed" at max. value.

    - The meter would react to changes in aperture in the stop-down mode (when practicable).
     
  8. Ooooops... The above should read, "the meter would not react to changes in aperture in the TTL full- aperture mode, because..."

    It thus would seem to me that it is possible to repair/adjust the meter even with your Zeiss lens.
     
  9. What do you mean by "TLL full-aperature mode" and also "stop-down mode" (in specific relation to the Super RE)? I know of these terms but I want to make sure we're on the same page.

    And yes, I thought that it should be no problem to test the light meter with any exakta lens! Unless someone can prove otherwise.
     
    Last edited: Dec 14, 2017
  10. Full aperture metering means, that where you turn the aperture ring on the lens, the iris will not open or close corresponding to the values you have selected; this will only happen when pressing the shutter, and until that moment the lens will remain at full aperture. However a link between the lens and the camera will tell the meter the selected aperture, and it will calculate the appropriate speed accordingly. This is possible with a Topcor lens but not for other Lenses in Exacta mount, because these have no link to the meter.

    You can meter in stop down mode with you camera in two ways:

    - by metering while depressing the DOF button, which will close the Iris at the selected value;

    - or, by using the button on your lens that will block the preset function, function, so that the Iris will open or close following the ring.
     
  11. ...and the saga continues...

    I brought my Topcon to a shop in reputable Portland, "Blue Moon Camera & Machine." However the said they would decline attempting to fix the light-meter and couldn't recommend a local shop who could help. I did buy the Topcor 50mm f1.8 even though my body still isn't fully functional. It's a smooth lens and I'm looking forward to snapping with it. Then I was able to play with a Super D they had for sale that did have a working light-meter, and it was fun to see the needle actually react to changes in light or settings.

    At this point (after the holidays) I might try to disassemble the body based on the service manual, and see if there are any obvious reasons why my needle won't budge. Then I'll go from there. Happy Holidays everyone!

    Oh and @bonsignore_ezio thanks for the info about the metering modes. It should be noted though that the camera can in fact be tested for a light-meter's reaction to light regardless of what lens is on the body. If there's a working battery, and a working light-meter, the Topcon needle should move as you point the camera around at various lighting situations.
     
  12. You can make the retaining screw for the shutter speed dial out of any reasonably long metric M1.4 screw, after filing the tip to conical shape.

    A lens spanner will help remove the ring around the PC terminal. You will need some 1/16" (or thicker) sheet brass or aluminum and a jeweler's saw to make a ring wrench to remove the disc on top of the film wind lever. You could also make a custom spanner wrench for the PC terminal from the sheet brass.

    A set of small JIS cross-point screwdrivers are recommended for the screws.

    A Topcor lens is not required to calibrate the meter, since it works perfectly fine with non-meter-coupled lenses. All you really need to do is prove that the aperture coupler for the lens properly moves the chains.
     
  13. Thank you for the tips John. How in depth does the camera dismantling have to get, in order to see if the aperture coupler is moving the chains? Or... to see if the black bland is blocking the exposure needle?

    From what I can research, I'll have to remove the top left cover plate and the top right cover plate. It looks like I won't have to remove the bottom cover plate.
     
  14. Steven, here's what I found under the covers of my "doner" body which turned out to have a non-working meter. "Brace yourself", as they say here in Australia ;-)
    Regards,
    Rif

    DSC_1490.JPG
     
  15. It should not be necessary to remove the top right or front cover plate to work on the meter. The top left, as in the picture above, should be enough. I think that's also enough to check every wire, resistor, and the CdS cell with an ohmmeter. (You really want to have an ohmmeter.)

    If the wires to the CdS cell in the mirror have broken, it's a huge teardown, and no parts available anyway.

    In the picture above, the chain that goes to the aperture feeler and the shutter speed/ASA dial "computes" the EV. The chain that is dangling normally has a pulley on the end, which the "computing" chain loops around. That chain is the one that rotates the meter body.

    The chains are very durable, highly unlikely to fail.

    Since the meter has to rotate, the two electrical connections to it are one possible problem area. (One is to the camera body, which is "common".) But the most fragile thing on the meter is the windings, and their soldered connections at the end.

    Your hope is that something is just mechanically stuck in the meter area, like the pointer being snagged on one of the stops.
     
    arif_raja|1 likes this.
  16. Hello everybody,
    sorry for necroing this thread... I'm a bit Topcon lover myself.

    I got a very well preserved Super D with somehow misbehaving light meter. It underexposes the image by 2+EV (when comparing to a A7 or other Topcon bodies). First I thought it would be the battery - 1.35V vs 1.5V. Other bodies work fine with it. So this is not an issue.

    Mechanically the exposimeter subsystem is perfect - chain links, default ranges, etc. Alignment tests results are OK according the repair guide.

    In other words - the light meter needle suggests 1/125sec, f/2.8 with 100 ASA indoors. That's not correct.

    My last suspect is the electronic part of the light meter. Connection wires seems to be soldered OK. So maybe when a 'serial' resistor loses its rated resistance it could lead to excessive current and thus resulting in greater than expected needle deviation. Thus it might worth a try to check resistance of the resistors.

    Thanks
     
  17. Some of the resistors were selected. I would be surprised if a resistor chaned value I'd suspect characteristic of CdS cell changed. Broken wire would be total failure.

    But just follow the procedures in the service manual. Calibrate light source with another Super D, then follow instructions.
     
  18. Some of the resistors were selected. I would be surprised if a resistor chaned value I'd suspect characteristic of CdS cell changed. Broken wire would be total failure.

    But just follow the procedures in the service manual. Calibrate light source with another Super D, then follow instructions.
     
  19. John, could you, please, elaborate on the "follow the procedures in the service manual" part?

    The service manual contains a whole section called 'Exposure meter adjustments'. It also features a troubleshooting procedures and more. Which procedure described there you recommend as the easiest one?

    Currently, that particular Super D body has top and front parts removed as per the service manual.

    Thanks a lot
     
  20. For future consideration, since you are handy enough to get inside your camera, once you solve your meter issues, see where you can mount a diode in series with the positive battery terminal to step the voltage of a standard 675 (1.5v) battery down to 1.37v. There is lots on the web about this. I modified my Nikon F's this way and the meter is fine with it.
     

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