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IV - REPAIR AND ADJUSTMENTS

This section of the manual is primarily devoted

to disassembly/reassembly procedures. These

procedures provide step by step instructions

aimed at guiding the technician through

the intricacies of SX-70 camera repair. The

procedures cover such things as replacement

of improper linkages or connections, repair of

electrical malfunctions, and adjustments needed

to return the camera to proper operation.

It should be stressed that these procedures are

intented to serve as guides for the experienced

repair technician. Except where noted otherwise,

the actual repair procedure to be used is left

to the discretion of trained personnel. Their

combination of training and experience should be

sufficient to allow repair personnel to make on the

spot judgements

to the best method of repair.

A major factor which must be considered is the

trade-off between time and cost materials. If the

repair is easy and feasible from a cost viewpoint,

it should be made. Otherwise, replacement of a

part or sub-assembly is the proper choice.

There is one other general note that pertains to

SX-70 camera repair. Occasionally, screw holes

in the plastic become stripped. This is most apt to

occur in the counter mouints, the motor mounts

and where the rear upper inner frame meets the

outerplate. To make an effective repair when

this happens, replace the original screw with an

oversize screw or insert a thin sliver of plastic

into the stripped hole before the original screw

is returned.

The spread rolls in the SX-70 camera are gear

driven by the main gear train. Thus, in addition

to wear or damage to the rolls, it is possible to

encounter wear and/or damage to the drive gear.

Regardless of the nature of the malfunction,

the complete assembly must be replaced. The

following paragraphs describe the replacement

procedure.

Removal

1. Erect the camera to picture taking configuration.
2. Open the front cover by depressing the front

cover release latch on the right side of the

camera bed.

3. Apply pressure to the side of the cover adjacent

to the cover hing aera. Press toward the gear

train side of the camera. This will release the

front cover. On newer models, detach the front

cover from the right side (gear train side) only.
4. inspect and clean the rollers and gears with

a Q-tip moistened in water. If film developer is

observed under the light shield or in the film

catcher spring aera, the front cover housing

must be repaced.
5. If necessary, as described above, replace the

front cover housing and test.
6. If the spread roll assembly is to be removed,

strip the leather from the cover. (Start pulling

the leather from the back and pull toward the

film exit. Do not start at the film exit.) Take out

two screws which secure the spread rollers to

the inside of the front cover, and remove the roll

assembly from the cover.

Installation

1. Position the spread roll assembly in the front

cover so that the gears will mate with the main

gear train when the cover is in place.
2. Install and tighten the two retaining screws

used to secure the rolls.

NOTE : A new sefl-tapping, square socket

head, coarse thread screw, PIN 705564 is

used to effect a repair of stripped thread in the

front cover assembly when installing a spread

system assembly. If the hole was stripped

during disassembly, the new screw will permit

easy reassembly. (This screw is standard on

newer cameras.)

A new square screwdriver tool bit. PIN 11867, is

available from Waltham Parts Dept.
3. Position the front cover housing on the camera.
4. Install the decorative leather covering. Make

sure the film exit is not covered by the leather.
5. Install the front cover by squeezing the sides

of the cover just enough to engage the hinge on

the pivot points of the bottom plate.
6. Close the cover and check the camera for

proper operation.

NOTE : If mishandling or dropping of the

camera causes breakage of the extruded metal

studs used to secure and pivot the front cover,

no repair is possible. Must replace the inner

camera back assembly.

Figure 4-1 illustrated the studs mentioned.

INTRODUCTION

A. FRONT COVER/SPREAD ROLL ASSEMBLY

Содержание Land SX-70

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Страница 3: ...ck therefore the batteries are always fresh as the film The four element lens has a maximum aperture of f 8 and a focusing rang from 10 4 inches to infinity The shutter is automatically controlled by a photocell and electronic timing Electrical to mechanical energy conversion is accomplished by two solenoids and a motor There are no separate diaphragm adjustement The shutter opening and closing ti...

Страница 4: ... sheet of film development takes place outside the camera and can be observed by the operator As soon as the print is ejected the mechanism completes its cycle to prepare for the next exposure Following thenth exposure the flash circuit is inhibited until a fresh film is inserted Normal operation will resume when the camera is reloaded The following paragraphs describe the electro mechanicalevents...

Страница 5: ... be inserted or an exhausted pack can be removed A fresh film pack is loaded into the film chamber observing color coding Figure 1 5 Under certain circunstances a partially used pack could be inserted but this action will cause some deviation in the normal counting sequence The battery is a part of each film pack and the two exposed terminals on the pack engage two contacts within the film chamber...

Страница 6: ...plished through a reflect system Figure 1 8 A In the viewing mode the image passes through the lens to a fixed mirror which reflects it down to the Fresnel viewing screen The viewing path from the viewfinder eyepiece lens is from a parabolic mirror and wafer lens off the fixed mirror to the Fresnel screen On most cameras the Fresnel screen contains a circular split image aera which is used to focu...

Страница 7: ...inged Fresnel viewing screen is swung upward and comes to rest in front of the fixed viewing mirror Figure 1 8 B The shutter opens and closes to perform the exposure function A first surfaced taking mirror is fastened to the underside of the Fresnel carrier assembly Figure 1 8 Viewing and shooting ...

Страница 8: ...ever there is no negative to pell off and discard The SX 70 accepts a special 10 lamp flash bar that plugs into a receptacle directly over the camera lens There are five lamps in a rowon either side of the bar which must be removed rotated and reinserted after the fifth lamp has been fired Figure 1 9 Insering a flash into the flash socket closes switch S2 in the socket This action sets up the shut...

Страница 9: ...d position to a suitable aperture The two blades then reverse direction and again shut off the optical path These same two blades also contain a similar although differently shaped pair of cutouts that open and close the light path to the photocell in like manner In the following description the functions of photocell cutouts is deferred until the action of the shutter cutouts is explained althoug...

Страница 10: ...apidly moves the shutter blades to the closed position When the solenoid has reached the end of its stroke shutter closed it no longer requires maximum current to hold it at that postion Switch S4 located on solenoid 1 closes CB and activates an electronic circuit called the POWER DOWN CIRCUIT This reduces power Figure 1 11 B Operation Figure 1 11 A Location Arrangement of internal parts ...

Страница 11: ...otocell is transformed electronically to regulate the lenght of time the fiml is exposed The shape of the opening in the shutter blades and the motion of the blades is such that all of the factors involved are continously variable throughout the exposure period this fact however is a design consideration and should not confuse the theory of the shutter operation from a maintenance point of view Wh...

Страница 12: ...e shutter opening is related to camera to subject distance thus compensating for the flashbulb to subject distance to give proper flash exposure As a solenoid 1 de energizes switch S4 moves from the CB position to the CA position This switch conects VCC to the FFA Figure 1 13 A Interceptor link Solenoid 2 S2 operation Solenoid de energized When the flash delay period reaches completion the circuit...

Страница 13: ...Figure 1 14 S5 being opened by the recock ram Gear train Figure 1 13 B Interceptor link Solenoid 2 S2 operation Solenoid energized ...

Страница 14: ...sh timing interval the circuit energizes solenoid 1 the shutter closes and the sequence proceeds as in the ambient light mode If the bulbs in the flash bar are all used when the operator attemps to make a flash exposure all of the previously described circuitly will function up to the actual firing of the flash lamp Since there is no lamp to ignite no flash firing current will be drawn There will ...

Страница 15: ...e 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 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 ...

Страница 16: ...and parabolic miror Figure 2 2 Viewfinder optics exposing The special Fresnel pronouced Freh nell screen is employed to enhance the viewing image by increasing the brightness and defintion If a matte white surface were substituted for the Fresnel screen an image would still be visible However the light rays striking nearest the corners of the screen meet the screen at a more oblique angle than the...

Страница 17: ... with a matte surface The ribbed surface of the lenticular screen narrows the angle of reflectance but increases the brilliance of the image within teh viewing aera In summary the Fresnel satisfies three conditons 1 it enhances focusing by distributing light rays evenly across the entire viewing aera 2 it guarantees proper focusing by nature of its acting as a ground glass thus insuring that the s...

Страница 18: ...baffle is held down out of the optical path The SX 70 is unique both in its principles of operation and its functional design It can be considered as aan electronically controlled mechanical device An electronic control module substrate or ECM contains all of the electronic components with the exception of the motor control MCC integrated circuit and the flash fire assembly FFA Because the ECM is ...

Страница 19: ...tographer and it causes the camera to run through a complet exposure film delevery cycle b Switch S2 places the circuitry into the flash mode Switch S2 si closed when the flash bar is inserted into the FFA on the top of the shutter housing It commands the integrated circuit in the FFA to select the first unused flashbulb and to fire the bulb It also enables the ECM to energize solenoid 2 which lim...

Страница 20: ...a cycle d Switch S4 is tripped by an actuator on the plungerofsolenoid 1 theshutterbladeactuating solenoid Figure 2 8 NOTE WhenevertheSX 70shutterisdiscussed it must be noted that since the camera is a single lens reflex and focusing is accomplished through the taking lens the shutter s normal state si open not closed as in other Polaroid cameras When the shutter release button is pressed and the ...

Страница 21: ...e operator has released the exposure button S1 After the exposure and when the Fresnel carrier returns to the viewing position S5 is closed by the recock ram and stops the camera cycle f Switch S6 is closed by openong the camera to the picture taking position Its disconnects the negative side of the battery from the commun return ground when the camera is folded to assure the removal of power from...

Страница 22: ...b The operator opens the front cover Switch S7 opens and removes battery power from the camera 3 Function Sequence Switch Action Result 1 closes Initiates exposure cycle and causes circuitry to take and deliver the pictures 2 closes Connects circuitry to take flash pictures 3 opens Initiates Y 40 milliseconds delay Power down solenoid 2 in the flash mode 4 CA closes Controls power to solenoid 1 dr...

Страница 23: ...here is insufficient light to correctly operate the integration circuits the system will automaticall terminate the exposure within 14 to 30 seconds taken until mirror bounce has subsided d The operators closes and latches the front cover S7 closes power is apllied and the camera eject the dark slide NOTE During this action and in certain other operations other switches actuate and functions occur...

Страница 24: ...he ambient light level is high the picture may be made by ambient light without firing the flash Also if all the flash lamps are expended and a picture is taken an ambient light exposure will result The photographer will recognize this situtation by the absence of a flash However he may still get an acceptable picture the aperture in this case will be determined by the flash to subject distance m ...

Страница 25: ...o bring the split Fresnel image into focus a cam molded into the rear surface of the focus wheel moves the component identified as the cam follower assembly The trim link coupled to the trim assembly is pinned to the cam follower in such a way that follower movement is also directly influenced by the setting of the trim wheel The trim wheel is the lighten darken control on the photocell F SHUTTER ...

Страница 26: ... 2 is energized Fastened to the plunger is pull down bar when the plunger pulls this bar down it moves the interceptor into the position where it will intercept a pin the stop pin on the walking beam Figure 2 9 A Now when the shutter blades move towards the open position theywillbeinterruptedbythemechanism just described which means the maximum size of the blade opening aperture is determined by t...

Страница 27: ...elay 40 milliseconds delay which allows the Fresnel carrier to come to rest after its travel This eliminates bouncing caused by the sudden stop of the carrier on the mirror cover At the end of the Y delay power is removed from solenoid 1 allowing the spring to open the shutter for exposure and moving S4 from CB to CA position When the proper exposure level is reached the photocell trips the Schmit...

Страница 28: ...y is collected before the end of the flash delay the blades will be closed as in ambient picture However on newer cameras P configuration shutters the flash will fire whether or not sufficient ambient light si available At the end of the flash delay the blades at this point are open to the aperture dictated by focusing power is removed from solenoid 2 and the discharge flyback voltage triggers the...

Страница 29: ... counter Shutter close Shutter starts to open Starts integration ambient Motor starts Fresnel starts down Integration 20 to 35 ms Shutter at full open f 8 16 Mirror continue to rise Mirror at rest Y delay activated Solenoid 1 power up Solenoid 1 power up Shutter starts to close Motor braked Cam stopped at 20 Electronic latch ON S1 may be opened Cam rotates Mirror released OPENS 26 34 AMBIENT EXPOS...

Страница 30: ...f visible mechanical damage For this reason a well defined series of checks observations and tests must be followed This section of the manual defines these procedures Theprimarypurposeofanyfaultanalysisprogram is to reduce the investigation time to a minimum Thus it is not only important to establish a fixed routine but it is mandatory to acquire the maximum amount of information from each step o...

Страница 31: ...and flash simulator 6 Take flash pix at 10 4 check premature dark slide 7 Check for dirty rollers and film catcher spring C FINAL VISUAL 1 Check optical path 2 Fresnel cosmetics per standards chart Split image 3 Wafer and 3 eye lens 4 Entrance and exit pupil position D SHUTTER COSMETICS 1 Chrome 2 Lens conditions 3 S1 button and photocell conditon trim wheel decal 4 S1 remote and flash socket cond...

Страница 32: ...1 In use the system subsitutes for the film pack giving a steady reliable source of power a Plug the pack simulator into the power supply being careful to observe polarity ground is negative b Set the power supply switch to VOLTS and turn the supply ON c Adjust the output to the desired volatge 5 8v normal NOTE Except on Lafayette made units the power supply mete is not adequate to set the voltage...

Страница 33: ...gned with the bottom part of the line or it may be displaced to the right If displaced to the right acceptable it should still be touching the lower part of the line 5 If the upper part of the line is displaced to the right so far that it does not touch the lower part of the line or if it is displaced to the left out of tolerance the tolerance levels are exceeded and the camera must be rejected Co...

Страница 34: ...heel still set it its infinity position look through the camera while turing the lens This is done by maintaining pressure on the tool While turning it you will be able to see the target through the opening in the tool c When the image is sharpest release the special tool to reengage the refocused lens to the focus wheel Continue setp 6 Non Spring Loaded Idler Gears a Remove the camerar from the c...

Страница 35: ...g of the SX 70 camera The earlier model Comprehensive Tester Model A consists of three interrelated units the lightbox the electronics module and the power supply Figure 3 6 Comprehensive Tester Model B Figure 3 7 also consists of three interrelated units the Comparalumen calibrated ligh source the electronics module and the mounting horn or holding fixture The purpose of both tester models is to ...

Страница 36: ...Release the exposure button actuator All of the meters will reset automatically 8 Repeat steps 5 through 7 twice a total of three times The exposure readings observeted must be within specifications 9 Move the light level selector to 6 25 Repeat steps 5 through 7 The reading must agree with specifications 10 Move the light level selector to 800 Repeat steps 5 through 7 All readings must agree with...

Страница 37: ...the socket on the camera and close the S2 CLOSE OPEN SWITCH 9 Set the light level selector to 800 cdls ft 10 Set the flash mode aperture switch to 8 11 Block any light from the photocell on the camera using a square of cardboard or other material 12 Depress the exposure button and observe the APERTURE meter 13 Record the 8 APERTURE reading and compare it to the STANDARDS Chart 14 Remove the tape f...

Страница 38: ...top pushbutton on the electronics module and read the meter adding 1 stops to whatever the meter is indicating 4 Light Leak Tester Figure 3 8 Caution When using the light leak tester always hold the fixture so the camera is in the uppermost position witgh the lens pointing down There is no latching device on the fixture and the camera could slide off it the fixture were pointed down The light leak...

Страница 39: ...ixture trigger 3 Examine the camera for light leaks Gently flex the boot while looking for leaks Note the location of any light leaks You may see a small amount of light in the aera where the boot joins the shutter housing This is light emanating from the substrate and is normal Allow the camera cycle completion and remove the fixture 4 Turn off the power 5 Repair any light leaks noted in the prev...

Страница 40: ...ces of test equipment is that the simulator relies on an external power supply while the function tester ahs a built in power supply The steps listed in paragraph b Test apply to both units Remember if the shutter tests satisfactorily at 5 volts the test must be repeated at 6 4 volts Set up 1 Using a VOM check for shorts on the shutter before setting it on the tester Not necessary for plastic base...

Страница 41: ...Blades close motor runs Blades close motor runs Blades close motor runs no flash Blades close motor runs Blades close motor runs Blades open motor brakes Flash Mode flash array inserted into shutter Close S1 Open S5 Open S1 Open S3 Close S3 Close S5 Open F1 thru F5 consecutively repeating above test between each switch opening Blades close motor runs Blades close motor brakes Blades close motor br...

Страница 42: ...lash pictures are critically dependent on accurate focusing a poor viewfinder system will make the taking of good flash pictures difficult Failure Analysis Chart 5 will enable you to trace most problems in the viewing system to their source Corrective actions are shown and where they are complicated are presented in Section IV Presented here are several checks with require greater detail than the ...

Страница 43: ...age e To be within acceptable limits the pupil a bright circular image must appear in the center of the square opening in the face of the gage If the pupil is not in the center adjust the optics system according to instructions in Section IV Viewfinder Sytem 2 Entrance Pupil Test a Set the focus wheel to 10 4 b Hold the camera at arm s lenght with the taking lens toward you and a bright light sour...

Страница 44: ...th the marks shown in Section II of the chart If the mark exceeds that shown on the chart the Fresnel is not acceptable c ViewtheFrenelscreenagainstthebackground of Section III on the chart The conditions shown on the chart are the maximum acceptable limits for Fresnel defects If the Fresnel being examined has defects which go beyond those shown on the chart reject the Fresnel Note that an illustr...

Страница 45: ...ee parts one CAMERAANALYSIS forproblemanalysis when the camera is completely assembled two OPTICAL ANALYSIS for analysis of the viewfinder parts three SHUTTER ANALYSIS for detailed shutter analysis The SHUTTER ANALYSIS charts should be used only after the shutter has been unsoldered from the camera If repairs and or replacements are indicated the procedures are described in Section IV ...

Страница 46: ... watt resistor across the VCC and NPN terminals as shown This procedure does not apply to mid cycle shutdown Refer to the Failure Analysis Charts NOTE One 10 pad flex circuits these are the TP6 and TP30 terminals One 8 pad circuits these are TP4 and TP21 terminals One 7 pad flex circuits where the PNP pad is eliminated the NPN terminal is located directly adjacent to the VCC terminal Refer to the ...

Страница 47: ... familiarity with the system is gained repair people can rely on the failure analysis charts to troubleshoot camera problems When the charts lead you to a repair procedure refer to Section IV Repairs and Adjustments for the necessary information Set up the test equipment as shown in Figure 3 18 The film pack simulator is inserted into the camera and the negative lead from the VOM is connected to c...

Страница 48: ......

Страница 49: ...ont cover release latch on the right side of the camera bed 3 Applypressuretothesideofthecoveradjacent to the cover hing aera Press toward the gear train side of the camera This will release the front cover On newer models detach the front cover from the right side gear train side only 4 inspect and clean the rollers and gears with a Q tip moistened in water If film developer is observed under the...

Страница 50: ...hereby causing excess play between the latch and retainer To resolve this problem perform the following procedures a Confirm that problem is not caused by loose screws on the spread system assembly by closing the front cover and while rocking it slightly observing for excessive play b Two vendors produce the spread system assembly bracket Figure 4 2 One vendor Ramcel makes the bracket with a retai...

Страница 51: ...Figure 4 4 Comparison of decal before and after front cover closure Figure 4 3 Bending the stop latch ...

Страница 52: ...captures the spread system frame When making any repairs requiirng replacement of either the spread system or the front cover assembly replace the old spread system with a new one If you install a new spread system in an old front cover you must remove the light seal before installing the new spread system The new light seal is adhered directly to the spreader before the spreader is installed in t...

Страница 53: ...ts surface damaged beyond cleaning Should any of these faults be evidenced replace the assembly NOTE On older cameras a coding system is used to match Fresnels and mirror covers When changing mirror cover and Fresnel assemblies correct color coding must be employed to prevent unacceptable tolerance buildup This is usually demonstrated by difficult cloding the camera etc The chart below shows the c...

Страница 54: ...the camera then slide the cover from the assembly 7 remove the inner frame to boot retainer screws Figure 4 8 8 Remove the four shutter housing retaining screws from the rear of the shutter mounting hinge bracket Figure 4 9 Check for square head or Bristol head screw Replace with same type Caution While the shutter is detached from the mounting bracket make sure no mechanical stress is put on the ...

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