Miranda Viewfinder Screens
|Miranda's special viewfinder system is wonderful in application of
special viewing options, and it is also straightforward and accessible to repair. It
is actually a well sealed unit, but over a long period, the elements may become dusty or
tarnished, and the viewfinder loses contrast and brightness. Every now and then I find a
particularly grungy camera, or one with a stained or damaged screen, which simply begs to
be repaired. Please read at least "MOST IMPORTANT
ASSEMBLY NOTE" at the bottom of this page.
The diagrams below relate to models with built-in match needle metering. For earlier models, the system is a little simpler, and cruder using separate brass shim pieces instead of pre-fabricated exact shim frames. I've described this briefly for the FV model here.
If you don't need to dismantle the whole system, then I would recommend not doing so. Very often the top condensor lens is grimy or cracked, and that's as far as you need to go. The screen can be dusted off with compressed air in situ. The screen position within the camera is fixed, centering of the viewed image is done with adjustments to the mirror itself.
|The diagrams and instructions below are from the disassembly of a Sensorex II, serial number 8322088. With the prism removed, there is a row of components from top to bottom visible down to the focus screen. It is possible to remove and replace all the viewfinder components without having to remove any of the meter parts. All meter models have a similar construction, with the components necessary to accomodate the match needle metering. The meter coil in all instances is situated under the left hand top plate, and the meter needle and follower arm protrude through the side of the finder recess to appear above the focussing screen.|
|Start by selecting the correct screwdriver (straight or phillips head, depending on the model) and gently unscrew the six screws holding down the top plate (1). Do this evenly, since the plate will be lightly spring loaded and tends to jump off. The next component is the condensor lens (2) which can be carefully lifted up. (For non-metered models, generally the condensor lens faces convex upwards, for metered models, the convex side faces downwards. Take particular care to establish which way your camera is set up BEFORE taking this top lens out.) Next, remove the plate spring (3) then the black plate with meter needle index (4) is next. This can be carefully extracted towards the right hand side away from the meter needles.|
|The main screen (5) is next, and it can be tricky. The
meter needles sit just above this screen. You must avoid getting serious fingerprints or
tool marks on either surface. The focus screen itself is on the underside, and finely
engraved fresnel rings on the top side.
I found the easiest method is to gently push up on the right hand side from underneath, inside the mirror chamber. Use a soft q-tip, or carefully padded tweezers. Once the right hand edge is above the top of the finder edge, you can carefully extract it sideways while avoiding the meter needles above it.
|The last components are straightforward to extract around the meter needles. Watch carefully for the sequence and orientation, since (6) and (7) are exact thickness shim components. They may be tapered, although I'm not sure on this point. Part (8) is a black flocked mount and little skirt acting as a light trap around the edge of the finder base.|
|Now you can clearly see the meter needles in this fully disassembled view.|
|By now, you should have a row of identifiable parts lined up in sequence similar to the row below:|
SERVICING YOU CAN DO
The screen is different. Don't use any solvent or cleaner, unless you have specific knowledge about this! If the screen is only dusty, I recommend compressed air (from a can) or an incredibly gentle brush. For stained screens, I have been successful with warm water with soft liquid soap, very gentle finger washing. Rinse with clean water and allow to dry naturally.
As a radical non-collector sidetrack, installing another newer type of screen may be feasible. I tried the Minolta Acute Matte for size, and it looked very promising, although I hadn't time to completely test it.The new split image rangefinder and enhanced generation screen showed significant improvement in the viewfinder.
Mostly the reverse procedure of the above, paying particular attention to keeping the screen (5) fingerprint and dust free, carefully putting the other parts in sequence around the meter needles up to the final condensor lens (2) and the cover plate (1).
MOST IMPORTANT ASSEMBLY NOTE
(a) put condensor lens (2) in place, centered as close as possible. It
will be sitting uniformly on the flat spring (3) underneath.
|Here's all the components laid out again, in order:
best wishes to anyone brave enough to tackle their Miranda.
I would also appreciate feedback, comments, additional information