I have previously written about the Minolta XE-1; it was one of my favourite cameras. To my dismay, after a couple of years of non-use, when I looked into its viewfinder I noticed that the bottom half has become almost totally dark. I immediately suspected that this was caused by decomposing foam padding, just like in my Canon FX and Olympus OM-1 cameras. When I took the XE-1 apart, that is exactly what I found.
If your camera suffers from the same problem, or even before it reaches that stage, this is what you can do:
Getting access to the prism of a Minolta XE-1
Only the middle part of the top - the prism housing - has to come off. There are two screws at the back of the camera on either side of the viewfinder eye-piece, two black screws at the front on both sides of the prism housing, and two chrome screws that hold the front bit with the minolta logo. The viewfinder shutter switch also has to come out. Pry off the little leather cover to find a screw underneath.
Now, take off the cover of the prism. You'll find a circuit board on the top of the prism and lots of wires. No need to get scared; desoldering will not be required. The wires are long enough, so that the circuit board can be carefully raised. There are two screws at the rear of the circuit board to remove first.
Under the circuit board the prism is held down by a fork shaped metal part. Once this is removed, the prism can be taken out. The following picture shows all the components you would have removed from the camera if you got this far.
And this is what the camera looks like after the penta-prism has been removed:
The Minolta XE-1 / XE-7 penta-prism
The XE-1 has a rather elaborate penta-prism with all those extra bits glued on it for light metering and viewfinder information viewing. Unfortunately, this makes any kind of repair more difficult.
The darkening of the bottom half of the viewfinder was caused by the decomposing foam strip that stuck to the front of the prism. After many years, this foam padding tends to turn into a gluey substance and erodes away the paint and reflexive coating on the prism.
If you decide to make an attempt to remove the remaining foam, be very careful, because both the silver coating and the black paint are very thin and delicate. They rub off easily. I also found that alcohol dissolves the paint. Only small sections of the prism are coated with silver, probably in order to reduce costs. So, for instance, not the entire surface of the front pane is coated silver. (I should note that what is silver in color is in fact probably aluminium.)
Further reading:
- a similar problem with some Canon cameras
- some other camera and lens restoration work I have done
- common problems with older lenses
- cameras in my collection
On a different topic see Roland FP-30 'secrets'; playing GS instruments on the Roland FP-30 digital piano.
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This exact same problem has affected my Leica R3 camera.
ReplyDeleteOnce I remove the old foam, is it possible to leave it as is?
ReplyDeleteSorry if there is a very obvious answer to this question
The foam serves as padding, so it would probably be a good idea to put something there that does not decompose, perhaps a piece of felt, but not really necessary. Just be careful when you remove the foam so that the paint on the prism does come off with it.
DeleteThank you for your help. I was able to remove the foam off the prism, but didn't install a replacement. I still see a black line on the bottom of the viewfinder. However, this time it’s see-through. I assume it's because i didn't remove the foam residue from where that part off the prism makes contact with body perhaps. At least it looks better than before.
DeleteGot an XE5 with black specks in the prism. Maybe the same decomposing foam? Maybe I'll try to fix it this way, thanks for your tutorial!
ReplyDeleteRandom specks of dirt can be on the focusing screen. On the prism the dark area is usually larger. Try to determine the location first just by looking and thinking about how the light passes through the viewfinder.
Delete