Olympus OM-1 Repair Manual page 39

Mirror Operation:
1. When 9082 (Botton) is pressed, 8432 is pushed in the direction of (3)
to be released from 8425.
2. 8425 is pushed by 8448 in the direction of (4). (Fig. B)
3. Along with the movement of 8425, 8441 moves in the direction of (6)
to lift the mirror. (Fig. B)
4. When the 8441 moves in the direction of (6), 8439 is moved towards
(7) to transmit the mirror-lift up to the shutter.
Fig. C
8425-
Mirror Lifted
8423
8412
- 8419
5. 8425 is fixed in position by 8418, which acts as the shock absorber.
6. Upon receipt of the message from the shutter that the second curtain
has completed its run, 8419 is pressed in the direction of (8). (Fig. C)
7. When 8419 is released from 8412, 8412 is lowered by 8423.
8. 8425 is pressed down at the same time 8412 is lowered.
9. 8425 is locked by 8432. The mechanism returns to the original state
shown in Fig. A.