ASAHI PENTAX S3, Service Manual

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Diagram 30
6. Adjustment of Mechanical Hack.
The distance from the film guide rails to the helicoid seat (A15) affixed to the front cover (A05) is referred
to as " Mechanical Back," which should be adjusted to be 45.46 +/- 0.03 mm. Use the special gauges and
tools illustrated in Attachment 1, viz., 230N-A01-A, dial gauge, dial comparator, 230N A15 A and 230N-
A01-A2. First, on the dial comparator, place the special gauge 230N-A01-A to be followed by 230N A01
A2, and adjust the dial gauge to zero.
Then, remove 230N-A01-A2 and place the body to be tested as per the illustration of Diagram No. 31. Place
230N-A15-A on A15 and check the distance between the film guide rails and the gauge 230N-A15-A, at
which the distance is to be adjusted to be 50.46± 0.03mm, using the front cover adjust washers (A39) with
different thicknesses.
(Diagram 32)
The front cover adjust washers are available with the following thickness:
0.05 mm
0.1 mm 0.15 mm 0.2 mm
Diagram 31
Diagram 32
7. Adjustment of Viewfinder Focus.
Whenever optical parts have been replaced, or when assembly of all parts has been completed, focussing of
the viewfinder has to be checked and properly adjusted.
Usually a collimator is used for focus check. When a collimator is unavailable, however, use a distant thin
stick-like subject, for example, a lightning arrester located 200 meters or more away, as an infinity target.
While viewing through the viewfinder, turn the distance scale ring of the lens mounted. When bright
focussing at the infinity target is unattainable unless the lens is extended forward (as shown in Diagram 33),
turn the 3 focus adjust screws (B63) to the right, using the special tool 230K-B63-A, and push upward the
ground glass assembly.
(Diagram 34)
On the other hand, when bright focussing at the infinity target is unattainable even if the lens distance scale
is set at infinity, turn (B63) to the left, lowering the ground glass assembly.
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