| Author |
Message |
    
L_n_h
Tinkerer
Username: L_n_h
Post Number: 31
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 21, 2013 - 01:13 pm: | 
|
Users of Praktica MTL3 and 5 cameras will no doubt be aware of the design fault which occurs when the camera is jolted a bit too hard (usually running with it in my bag does it). The shutter or something basic jams and you can see nothing through the viewfinder but blackness. Nothing seems to unjam it apart from pointing the camera at something random and firing the shutter release, which unjams the fault and takes a photo as normal. (The resulting pic develops normally but tends to be blurred or wrongly exposed simply because one cannot do the usual focus/exposure adjustments while the camera is 'blind'). Is there any way to unjam the fault quickly without unscrewing the whole mechanism? (which I have done but this is not practical when outdoors). Perhaps we can just unscrew the lens and solve the problem from there? Anyone any ideas?
PS-It may not actually be the shutter which jams but some other moving part, like a mirror for instance, which may explain the complete blackness seen through viewfinder. |
Prasanna
Tinkerer
Username: Prasanna
Post Number: 93
Registered: 10-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 22, 2013 - 04:01 am: |
|
The mirror release lever is the problem. It is either the alignment that has changed or a spring that has lost its tension. Try removing the lens and reach inside to the left wall. You will find a small lever that holds the mirror up. Push that lever with a blunt plastic or wooden rod and the mirror will drop down. Then you will be ready to wind on. This problem exists with some other cameras too, such as, the Konica, Pentax SP series and the like. |
Thepurush
Tinkerer
Username: Thepurush
Post Number: 82
Registered: 01-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 22, 2013 - 10:28 am: |
|
In any SLR camera thre is a full sequece of events, which all must take place between pressof shutter release and camera comeing back to ready to wind again state. each event fires the next event, and if any event failes to execute then the camrea hangs uplike it happened in your case.
When you press shuuter release it is the mirror which lifts up first blocking viewfinder, next the first curtain opens, then 2nd curtain closes which relaeases mirror, which brings back camera to 'ready state again.
So in your case eithre the mirror failed to fully lift up thus not releasing 1st curtain, or shutter is in open condition, so 2nd curtain not released, or 2nd curtain not released with enough force to release mirror.
You need to let every one the state of shutter. You may try the following. Remove lense and see if the mirror is fully up ? if not try pressing it up, it may fire. Or you may try applying a light force on the shuuter blades themselves to check if 2nd curtain hasnt closed fully.
Now the remeidy depends on where wxactly the fault lies. Such problems r common when lubrication dries up in the mechanism. Asmall amount of oil at the right place(not just at any place) should set right such problem.
Good luck |
L_n_h
Tinkerer
Username: L_n_h
Post Number: 32
Registered: 09-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, March 23, 2013 - 06:46 am: |
|
Yes Prasanna, the mirror does drop down when the lever is pushed, which then restores vision in the viewfinder. The camera can then be fired as normal. Thanks for that tip.
It is interesting to note that Ive never had the mirror stick like this if I dont wind the film on after taking the previous shot (ie the little triangular tag is still visible in left of viewfinder). Maybe a only coincidence, or as Thepurush implies, the camera sequence needs to be completed before the circumstance for this fault can occur. Perhaps its worth making a habit of only winding on the film just before I actually take a pic.
Thanks again for your help! |
Thepurush
Tinkerer
Username: Thepurush
Post Number: 84
Registered: 01-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, March 24, 2013 - 12:06 am: |
|
Obviously the problem is in the last stage,the mirror isnt able to return on it own. Actually the mirror release lever it self is triggerd by the shuuter at the end of exposure. There appears to be friction somewhere in this linkage below mirror or the mechanism that triggers its release. Try examining this looking from front. Next time you get into this problem first try to push the arc shaped lever at the bottom of lense opening that pushes a pin on the back of lense to close aperture. Is this leve also controls the return? That is to be seen. |
|
