Canon A-1 Repair Manual page 64

The features of this mechanism are as follows:
1) The functioning of the new MD Coupler, mentioned
in section 4.6.1, prevents flow-type blurring of
pictures otherwise caused by Motor Drive MA.
2) Nonchattering signals SWS and SWS' are possible
due to the functioning of the microbrush.
3) Since the second shutter curtain signal releases
the wind stopper, it prevents accidental winding
while the shutter is functioning even during
long exposure times.
4) The many steel ball bearings used on the top and
bottom of the winder shaft increase reliability
and durability.
(3) Multiexposure Mechanism
Set HE lever
HE shaft
turn.
The compound gears
(CW) CCW
are disengaged from
each other
Winding the winding
Sprocket and spool de not
lever
turn
No t ch on winding shaft the
HE plate
CW
•
HE Lever resets.
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