Polaroid SX70 manual Introduction, Power Source, Lens, Viewing and Exposing System

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II - THEORY OF OPERATION

A. INTRODUCTION

A general description of the camera and the sequence of its functions is contained in Section I. In that section, detailed analysis of individual assemblies and electrical circuits was minimized so that emphasis could be placed on the intenelation-ship of various functions. In the following paragraphs, the individual groups of components are described in greater detail. The description are presented in the sequence in the commponents were mentioned in Section I.

B. POWER SOURCE

Power for the drive motor, the shutter electronics, and the flash array is supplied by a specially designed 6 volts battery incorporated in each 10 exposures film pack. When the pack is inserted into the camera, two contacts pads on the bottom surface of the pack engage two spring-loaded contacts on the inner bottom surface of the camera bottom plate. From these two points, it is distributed to its destinations by the copper foil strips of a flex circuit on the outer surface of the bottom plate.

The battery has adequate capacity to expose all 10 film frames with at least six months of expected shelf life.

C. LENS

The lens employed is a four element, glass lens of f/8 aperture with a focal lenght of 115mm. It has a focusing range of infinity down to 10,4 inches. Focusing is accomplished by movement of the front element only. Helical threads in the lens mount provide the linear lens elemet movement. Operation is by means of a geared focus wheel at the top of the shutter housing. There is no manualy adjustable diaphragm associated with the SX-70 lens.

D. VIEWING AND EXPOSING SYSTEM

When the camera is erected to picture taking configuration, the subject can be viewed through the collapsible viewfinder. Figures 2-1 and 2-2 show the two optical paths in the camera. Note the direction of the arrows. Reflected light from

Figure 2-1 Viewfinder optics (viewing)

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Contents Page Page General Description DescriptionOpening the Camera Camera OperationStarting the Automatic Mechanism Loading the Film packViewing and focusing Setting the exposure counterViewing and shooting Exposures using flash Completing the film packDeveloping the print Closing the camera Shutter Description Ambient Light Mode11 a Location & Arrangement of internal parts Shutter Description Flash Mode Page 14 S5 being opened by the recock ram Gear train Page Viewing and Exposing System Power SourceIntroduction LensViewfinder optics exposing Fresnel Figures 2-3 a and 2-3 BFresnel screen Camera Elctronics 1. General ViewfinderMirrors Flare baffleSX-70 Switch locations Switch functionsS3 Being opened by recock ram S4 Switch operating configurations Function Sequence Switch Function TablePage Flash Timing Sequence Chart Shutter, exploded view Shutter Mechanical Details FigureA Solenoid S2 operation Sequence of Operations Film Processing ComponentsPage Max Introduction Initial Tests III TroubleshootingSX-70 Cmaera Repair Inspection Procedure Test Equipment Operation Power supply and pack simulator FigureLocation of new collimator target Collimator FigureDisengaging the idler gear Comprehensive tester Comprehensive Testers -6Model B Camera tester Model B Camera Tester Light Leak Tester Figure Comparalumen Light Levels TableLight leak test system Flash Simulator Board Figure10 Manual camera tester Manual Function Tester FigureManual Function Test Sequence Exit Pupil Test Optical System13 Aligning the exit pupil gage Entrance Pupil TestCollimation USE of Analysis ChartsConcave Mirror Distortion Check Fresnel Quality Check16 Fresnel standards chart 18 Flex circuit terminal locations Camera/Shutter Isolation19 Test points on SX-70 shutters Camera Analysis ChartsPage Front COVER/SPREAD Roll Assembly InstallationRemoval Front cover hinge studs Repairs / Adjsutments Loose Front CoversBending the stop latch Interference Between Front and Bottom Covers Top Spread Roll LoosenessReplacing the Light Shield Cam Front cover light shield cam Mirror Cover / Boot AssemblyBoot retaining screws