As Ralph said it does take some work. The good thing is a set of jewelers screwdrivers does most of it. A spanner is needed for the screw on the wind lever but sometimes you can use a heavy rubber band to get a grip on it and unscrew it. The nut under the rewind knob is also undone with a spanner.
OK, you have your tools
#1 Set the shutter speed to "B" and the asa to 100. This is a reference point AND it takes tension off the spring on the metering resistor
There are two "hidden" screws on the body. The lens index with the red dot and the wind lever screw. Both the red dot and the black cover are pried off.
The dot I use a fine sewing needle to dig under it a bit. a drop of alcohol may help loosen it.
Remove the RW knob, the large spanner nut beneath it and the wind lever.
The red dot has to come off as well as the screws on the front plate., Lift off the plate.
Now take out all the remaining screws around the top cover and gently remove the cover. AS SOON AS YOU HAVE THE COVER OFF, Put the large spanner nut back on the RW shaft. this keeps the resistor from falling off. You're going to notice all the meter coupling is done with a heavy thread. You don't want to f**k this up.
As I recall, the circuit board covers the prism. There are two metal bracket holding the prism in place and possibly one or two pieces of black tape. Remove them.
The prism should lift out to one side and the focussing screen visible.
THE SCREEN, MASK AND CONDENSER ARE CLOSE TO THE METER NEEDLE. If this has shutter/aperture visible through the finder, be extremely careful. These can be knocked out of alignment by looking at them wrong.
THERE ARE THREE PARTS TO THE SCREEN! A condenser lens, a mask and the screen itself. The works will drop out if you invert the camera.
Reassembly is in reverse order. The screen itself has to be slipped under the needle PITA. Use something to keep from touching it while you're getting it in there. You do not want fingerprints on it(evidence)
