| Author |
Message |
    
Wim Abbeloos
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 01, 2005 - 07:47 am: | 
|
I have a couple of SLRs which have their mirrors stuck up and impossible to wind.
Nikkorex F
Canonflex
Pentax program A
Help would be very welome,
Wim Abbeloos |
Paolo Amedeo
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 01, 2005 - 08:32 am: |
|
Assuming that this is not caused by the camera have been dropped or other mechanical breakdowns, here are a series of some “low-tech tricks” that work most of the time.
Of course, this assumes that the second curtain of the shutter has reached the end-travel*.
I will put them in the order I would try. Note that, for any suggestion of “moving manually” a component, I mean that there should be no forcing and the only resistance that should be contrasted would be the resistance of some spring. Therefore Don't force anything in any case!
- Push the mirror more against the focusing screen and let it go (if it goes).
- If the camera has a depth-of-field control command, try pushing and releasing it several times.
- Try gently moving the lever that closes the diaphragm in the lens during the exposure.
- Yes, it sounds odd, however it work reliably on many cameras (especially old Canon and Minolta SRT series): hit the bottom back (preferentially on the left side) with the palm of your hand.
- Gently try to pull down the mirror and leave it where it stays (i.e. Minolta 9000 and other cameras) or let it free to jump back towards the screen.
If none of those techniques was successful, you need to try disengaging the mechanism to prevent double exposures, cock and shoot the camera several times.
In the majority of the cameras, this mechanism is a lever located on the bottom of the camera that "disappears" under the wheel/gear pivoted on the winding mechanism. It's a few years that I don't "play" with Canon A series, however I think that, in those cameras, this mechanism is instead on the top... I could be completely wrong on this... Do check first in the bottom, since it is much easier to open that side!
Good luck!
Paolo
* This stuff I am a bit hesitant to put it here since it could cause more damages than benefits: if the second curtain didn't make through completely, with a lot of care, extremely firm fingers and extra-clean hands, you can try to pull back the second curtain and let it go: if the blockage was "accidental", this time it should close completely and the mirror would drop back down. |
Wim Abbeloos
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 01, 2005 - 03:33 pm: |
|
In the majority of the cameras, this mechanism is a lever located on the bottom of the camera that "disappears" under the wheel/gear pivoted on the winding mechanism.
Can you please give me more details on how to do this? Is this below the bottom plate? |
Wim Abbeloos
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 02, 2005 - 04:17 am: |
|
I found the lever I assume you are talking about on the nikkorex F. When I hold this lever I am able to wind, but the mirror will not come down. I can pull the window down but as soon as I let it go it goes up again. There is no tension on the shutter release button.
On the canonflex I can get the mirror down by pulling a lever with my hands. When shutter button is pressed the mirror goes up half-way and then stops. It can be easily pused up with my hands but the shutter does not open. I can not wind. I have not removed teh bottom plate yet as I am unsure wether the rings on the bottom are left or right hand threads. They seem rather tight.
On the Pentax program A I can pull the mirror down by hand but it doesn't stay down. Not possible to wind, no tension on hsutter release. With batteries I do see a meter reading in the viewfinder. Have not removed bottom plate yet.
Help is still greatly appreciated. |
Paolo Amedeo
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 02, 2005 - 09:22 am: |
|
Hi Wim,
Sorry, I had the intention of digging among my "cadavers" taking a few pictures and sending to you, but I didn't have time to do it...
For the Canonflex, how you describe the problem, I think that the issue is with the lubrication of the mirror box: as general principle, when you push the release button on a mechanical camera, you trigger the mirror box: when the mirror reaches the top, a lever would release the first curtain.
The mirror mechanism contains some sort of dampers to slow down the mirror near the end of the run. I am not too familiar with the Canonflex. I have however a lot of experience with the Canon A series and I bet that they are substantially similar in the mechanics: the dumping is obtained by a system of gears and a freewheel (That's the typical noise of those cameras when they beg for lubrication...). I bet that the problem of yours is indeed that needs a bit of lubrication... I don't think that there are shortcuts for this: you need to take out top and bottom and remove the mirror block: generally the screws are hidden under the leatherettes of the front. As I said, I am not too familiar with this camera... However, a few years ago, with some training I was able to lubricate the mirror of a AE-1 (or similar) in less than one hour, with the complication of having to remove the electronic circuit... The tricky part is to detach the mirror block from the rest, since there are levers coupling it with the shutter mechanism. For any reason, don't force! Otherwise you will bend some piece...
I should have around a Pentax like yours or a similar model: as soon as I have time, I will take the bottom off and take some picture for you.
One thing that i nave found extremely useful while working on a camera is to take tons of digital pictures at different steps, especially of the pieces that are still in place and they should be disassembled next. Too many times you end up with pieces of metal that would technically fit in different directiona but they would work only in one...
Paolo |
Paolo Amedeo
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 02, 2005 - 11:19 pm: |
|
Hi Wim,
I have finally dug out of the pile a couple of Pentax (Super A and ME-F): both are identical for the "double-exposure prevention mechanism) In the following pictures the lever has been "moved out" with the screw driver and is pointed by the red arrow.
img_1 img_2
Actually, the ME-F has probably a similar problem like yours: a couple of years ago was working but the mirror was extremely slow. Now the mirror is stuck and the shutter will fire when the lever is released, since the mirror is not reset.
In this case there isn't any other alternative from disassembling the camera, taking out the mirror group, washing out the old, dried lube and apply some very light oil to the mirror mechanism....
Good luck!
Paolo |
|
