Praktica BMS Electronic

Ragondux · Sep 27, 2021

Hi all,

I recently bought a Prakitca BMS electronic that was supposed to be in working condition, but there appears to be a problem with the shutter. The aperture blades don't open, and one of them appears in the viewfinder (it moves around when I use the film advance lever).

I have already fixed stuck aperture blades in an Olympus Trip 35, so I am somewhat confident I should be able to take this one apart and access the aperture blades (I've found videos for similar models), however I am not sure what I'm looking for. Do you have any idea? The blades are not stuck, so what could it be? A broken spring?

Also, the mirror goes up and down when I advance the film, but it does not when I try to activate the shutter. There is a small click sound, but nothing seems to happen. Could it be just one single issue, or two separate ones? Or maybe I am just misunderstanding how it is supposed to work, since I've never tried fixing a reflex camera before.

Thanks in advance

4season · Sep 27, 2021

Shutter is supposed to block viewfinder during exposure, but why does yours appear to have oil stains?

Ragondux · Sep 27, 2021

The oil stains were probably left by my fingers
I guessed it was normal that the viewfinder was blocked during exposure, but then the plate doen't come down properly (it's the grey shape in both pictures). And also the shutter does not open.

AgX · Sep 27, 2021

4season said:
Shutter is supposed to block viewfinder during exposure.

I do not know of any Praktica model that got an eyepiece shutter.
(But there is the "uncocked" indicator in the L-series.)

chuck3565 · Sep 27, 2021

This is a long shot. Try using your fingernail to pull down the shutter blades, then try the film advance again. If this works, apply naptha to both sides of the shutter blades and repeatedly fire the shutter. Make sure to keep the naptha away from the prism. I have repaired L series shutter problems but only electronic problems with the B series.

AgX · Sep 27, 2021

But isn't the shutter proper, thus the blades-apparatus, the same?

4season · Sep 27, 2021

AgX said:
I do not know of any Praktica model that got an eyepiece shutter.

My Jenaflex (Praktica B200) does.

AgX · Sep 27, 2021

This is puzzling, as the B 200 manual advises in AE mode, if ones eye is off the eyepiece, to cover the eyepiece with a dedicated accessory cover to push over the eyepiece.

Ragondux · Sep 28, 2021

Pulling down the shutter blades manually didn't help
Also, the new battery I put in now seems dead, so I guess there are other issues. In which case I probably won't be able to fix it.

John Koehrer · Sep 28, 2021

You won't see shutter blades in the finder. Could be the mirror is not in the right position of something has been dislodged and moved into the light path.

AgX · Sep 29, 2021

AgX said:
But isn't the shutter proper, thus the blades-apparatus, the same?

"...as in the L-series", I meant.

4season · Sep 29, 2021

This is how my Jenaflex behaves.

AgX · Sep 29, 2021

I am puzzled, as said. The B 200 manual I looked into indicates the contrary to what you show. And a quick look at the net did not turned up any hint at such.
Leaving that manual aside, did nobody find it worth mentioning such?

AgX · Sep 29, 2021

Can't it be your sample has got some defect similar to the one of the OP?

I still assume the shutter proper to be the same as with the L-series, but in suchg case of defect such must have happened to the L-series too...

4season · Sep 29, 2021

AgX said:
I am puzzled, as said. The B 200 manual I looked into indicates the contrary to what you show.

The manual is correct: If don't have your eye at the eyepiece, you'll want to shade it lest stray light cause erroneous readings. It's possible that my camera is faulty, but I've tested it with film, and it seems to be working fine.

AgX · Sep 29, 2021

For plain reading it does not matter, as one needs to bring ones eye to the finder to see the metering result, unless a B-model has meter-memory.
For metering in AE mode the metering is done just at releasing, or just before the mirror flipping up. In this case, if there is such eyepiece shutter, it must close before the reading is taken, to be useful. In any case before the mirror goes up. But then it hardly could be coupled with the shutter.

AgX · Oct 1, 2021

I have been looking at photos of the L-series shutter, assuming that its blades apparatus is the same, wondering how blades could get up into the eyepiece, moreover the shutter seemingly still somehow working as 4season indicated.

Maybe the OP puts up a post at the Praktica-L repair thread to bring some L-series cracks to this thread for a look.

4season · Oct 1, 2021

AgX said:
I have been looking at photos of the L-series shutter, assuming that its blades apparatus is the same, wondering how blades could get up into the eyepiece, moreover the shutter seemingly still somehow working as 4season indicated.

It's logical in an automatic camera capable of long exposures.

AgX · Oct 1, 2021

I meant appearing in the eyepiece by failure.

A appearance by design is not logical at all as I explained in post #17.

I only know of one 35mm SLR with an automatic eyepiece shutter. And there this is not part of the film shutter, moreover the camera is of complete different design, where such eyepiece shutter is of bigger necessity.

Edit_R · May 16, 2024

Hello!
I just found this forum convo when i was searching about my Jenaflex ac-1 (I bougth on second hand) that appears to have a similar problem, I wonder if you find a solution?
I put a new battery and a Film and the camera still didn't respond she's freezed on this position, and the cocking lever is stuck

Thank you

Praktica BMS Electronic

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