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Olympus OM-4 Service Manual Part 4 of 4

1. r Voltage as analog variable converted into high current reverse to the log compression Charging of capacitor for regeneration Indicated time charged integrated into capacitor 13 Regenerating capacitor separate from that for DIRECT mode udgment o integral secaseveee Upon charging of indicated time comparator is inverted 14 MG deenergized in indicated time 146 3 Exposure Program Flow Chart Mechanicai Release SU eine Fiow chart for shutter contro button OK Electric circuit and power supply hoid Mirror UP Main SW ON eessees Detected by INTA Shutter control circuit ON aje sj Power NG 1st shutter bind travels MGION pm i pipes MG2 OFF E Shutter control circuit OFF Minor DOWN weesworr END 1 47 4 Indication amp Exposure Time Chart z z E ec 9 6 2 S 2 5 A button Mirror UP completes 2nd shutter SIE l 5 f 3 0 blind stop n i gs a e H Mirror UP 1st shutter blind starts Mirror DOWN DOWN Toine a E 3 2 1 22mS tstshutter completes f G 40nS blind stops ss dU Indication SW LL i ZEE MSW EE Trigger W Or Light meas 2 2 Qmn urement Latch indication with no indication of D m indication light measurement 10 10 10sec Indicator I illuminator MG2 T DE e a t a
2. 2 65V for locking and 2 90V for unlocking R109 Thyristor gate pull down resistor Cooperates with C102 to prevent thyristor from functioning erroneously due to unwant ed surge noise etc R110 Gate trigger resistor Cooperates with C103 to turn ON thyristor R111 For reducing impedance oi the negative terminal of C103 while Q101 is made non conductive and maintaining the terminal at sufficient potential while Q101 is made conductive R112 Current control resistor For limiting base current of Q401 R113 Current limiting resistor For limiting base current of Q103 R114 Clock resistor For creating system clock of the CPU R115 Current limiting resistor For limiting base current of Q106 R116 current limiting resistor For limiting base current of R105 R117 Current limiting resistor For limiting base current of Q104 R118 Current limiting resistor For limiting collector current of R104 R1 19 Current limiting resistor For limiting collector current of Q105 1 19 20 21 22 23 24 25 26 27 28 29 30 31 R120 Current limiting resistor For limiting coliector current of Q106 R121 Positive feedback resistor For forming a positive feedback loop which prevents leak current by maintaining the same potential as that on the anode side of the head amplifier R122 Positive feedback resistor For forming a positive feedback loop which prevents leak current by maintaining
3. SW113 Mode switch These switches are used for setting up the battery check mode and switching betweer the AUTO and MANUAL modes respectively SW105 Battery check Battery check Mode selector 6 SW106 Lamp switch For inputting lamp ignition signal SW106 10 11 12 13 14 SW107 SPOT switch 18 For inputting spot signal SW108 HILIGHT switch For inputting HILIGHT CONTROL signal SW109 SHADOW switch For inputting SHADOW control signal SW110 GLR mount CLR switch For clearing the SPOT input or MEMO input which has been inputted at the stage of lens mounting or dismounting The CLR and mount CLR switch circuits are connected in series l SW111 Display switch For starting light measurement SW112 MEMO switch For inputting MEMO signal SW113 Mode switch For selecting the MANUAL or AUTO mode SW114 Reset switch For automatically resetting the camera in switching from the MANUAL to AUTO mode or vice versa MEMO CLR FP switch When a strobe especially one offered by a manufacturer other than OLYMPUS is used in combination with the synchronous socket a high voltage is generated at the shoe input terminal during charging This switch is turned OFF to prevent electrical shock hazard while the mirroris lowered FP switch Body ground GEL To anode of SCR MD switch Motor drive switch For interlocking the motor drive or film winder with the camera MD switch To
4. o In the SPOT MANUAL mode exposure level is calculated from spot light measurement value BV shutter time TV ASA value SV corrected value CV and aperture value AV and indicated by the bar 3 Light measurement value and calculated spot value are indicated by tip of the bar 4 In the SPOT mode maximum or mini mum brightness point is displayed and then the predetermined value is indicated when maximum brightness in the HI LIGHT CONTROL mode or m nimum brightness in the SHADOW CONTROL mode is newly inputted for recalculation when the camera is newly set in the HILIGHT CONTROL or SHADOW CON TROL mode or when maximum or minimum brightness varied by overflaw ing spot input 1 25 e Spot secanning point 1 Spot scanning point is indicated in the SPOT mode of the AUTO or MANUAL mode In the AUTO mode spot input value spot light measurement value of object to be photographed BV ASA value SV and aperture value AV are calculated to indicate shutter time to be used as standard exposure level Indication in th same 1 3 EV steps as those for bar indication In the MANUAL mode spot input value spot light measurement value of object to be photographed BV ASA value SV aperture value AV and shutter speed TV are calculated to indicate exposure level by the dot Indication in the same 1 3 EV steps as those for the bar indication For shifting all the indications due to variations of AV
5. 7 A mechanical shutter speed of 1 60 sec is available 8 The shutter can provide high speeds up to 1 2000 sec Owing to these features Model OM 4 permits freely controlling xposure for photographing in rear light and depending on difference in brightness of background Further the viewfinder is so designed as to facili tate focusing even for short sighted and long sighted persons In addition the mechanical shutter time is prepared so as not to lose shuttering change shouid the battery becomes exhausted Therefore Model OM 4 has opened a far wider photographing range In order to achieve this purpose Model OM 4 adopts sophisticated circuits mentioned below 1 Auto circuit of direct light measurement type 2 Auto circuit of light measurement memory type SPOT Further the instrument incorporates two unique exposure control EE mechanisms Moreover manual circuit high light circuit shadow circuit strobe circuit memory and so on are built in to compose the high grade circuit of Model OM 4 The most advanced 4 bit microcomputer and bipolar IC have been developed as the main com ponents of the electrical circuits in addition OM 4 is equipped with specially developed high performance mechanisms such as shutter mechanism featuring high accuracy high speed travelling stability high speed of 1 2000 sec as well as mechanical speed of 1 60 sec electromagnetic shutter lock mechanism mecha ni
6. Bulb mecha 1 60 No indication within the viewfinder 2 Application of Photographic Modes 2 1 Auto Mode 1 Automatic exposure by average light measure ment average direct auto Average of BV brightness of object to be photographed is measured and a bar is displayed on LCD as a shutter speed TV to be adopted as standard exposure level based on AV aperture value SV ISO and CV corrected exposure value o When the main switch is turned ON the mirror is raised to set up the stop down con dition and automatic exposure is perfomed in the direct light measurement mode in which reflection light from the shutter blind and film surface is measured s e the shutter is released 2 Automatic exposure by spot light measure ment spot auto o The spot auto mode is set up by turning ON the SPOT key in the average direct auto mode c In this mode BV brightness of object to be photographed is measured at a spot and the measured value is entered A dot and a bar are displayed on LCDs as a shutter speed to be adopted as standard exposure level based on AV and SV o The bar only is shifted for correcting exposure c When the SPOT key is turned ON in the spot auto mode a new spot measurement value is entered A shutter speed determined based on the value is indicated by a dot and another shutter speed determined by simply averaging the entered spot measurement value is indicated by
7. CONTROL mode tip of the bar is located 2 EV on the negative side of the maximum brightness value of the spot inputs In the SHADOW CONTROL mode tip of the bar is located 2 2 3 EV on the positive side of the minimum brightness value of the spot inputs When the main switch is in this mode fiim is exposed at the set shutter speed The camera is set in the average manual mode after the shutter is released 4 Manual strobe o The strobe photographing mode is set up by turning ON the strobe power source in each manual mode The spot mode is automatically cleared by setting up the manual strobe mode The bar indication in the manual strobe mode is the same as that in the average manual mode When the main switch is turned ON in the manual strobe mode the strobe flashes and film is exposed at the set shutter speed When the strobe power source is turned OFF in the manual mode the camera is set in the average manual mode The memory function is unusable in the manual mode 2 3 Bulb Mode The bulb mode is set up when shutter speed is set at B c The bulb mode is set up regardless of mode switch setting c When the strobe power source is turned OFF The LCDs provide no indication in this mode l The magnet is ineffective for control when the main switch is turned ON in this mode The battery check function is operative in this mode 2 When the strobe power source is turned ON The LCD provides n
8. cam of gear A is brought into contact with K lever 2 to push part B of the K lever outside Therefore the R claw disengages from the gear plate B and the 2nd shutter blind starts When the SD is set at 1 2Q00 sec the bulb lever is pushed leftward part A Since the R claw and K lever 2 are pushed leftward by the bulb lever it is impossible to stop the gear 8 Since a gap is formed in part C the R claw is capable of control ling the 2nd shutter blind CES0470 Ag d CES0480 f Part D CE504100 Part B 2 Electromagnetic Shutter Lock Mechanism Before film winding Shutter lock Releasing claw A CE50100 SL Lever CE530900 FD MES OF 2 vA gal Gm Vo EVE X A ter T gll t m M charging lever 25176706 Ni After film winding Releasing shutter lock K Plate B CES91300 A Lever CES30300 ES Reset lever CE502600 Charge lever CE530600 3 Mechanism to Prevent Film Winding during Exposure Time Before film winding L Pin screw CE573500 Wind stopper CA883100 M charging lever 2176700 KM Lever ZC452800 l Ai M Release CE525400 After film winding 4 Dioptry Adjusting Mechanism By turning F Shaft CE545500 FO Frame ZJ 177700 and FT Frame ZJ177800 are shifted for dioptry adjustment k PUTB2135N E 46400 IV DESCRIPTION OF ELECTRIC CIRCUITS The electric circuit of Model OM 4 consists of microcomputer 1C101 bipolar IC 1C1021 head amplifier 1C103
9. circuit 7 Synchronous switch X SW 11 DAC AV TV Lock adjusting circuit When the synchronous switch X is turned DAC adjustment ON pin No 59 is set at H level to make the Circuit for adjusting D A converter flashing thyristor conductive and flash the TV AV adjustment strobe Circuit for generating standard voltage for TV AN Synchronous switch TV AV Vref circuit Circuit for generating standard voltage for TV AV TV AV TV output and AV output Lock adjusting circuit B Offset adjusting circuit Circuit for adjusting lock voltage level This circuit is arranged for offset adjusting for the comparator of the bipolar IC DAC AV TV Lock adjusting circuit Offset adjusting circuit 9 Standard current adjusting circuit Since the BV output varies with temperature it is necessary to adjust the standard current accordingly This circuit is adopted for this adjustment Standard current adjusting circuit 12 Spot BV adjusting amp average BV adjusting circuit BV Resistor for adjusting indication BV BV Average BV output from BV BV Spot BV output 10 CV SV EE adjusting circuit Average BC adjusting Spot BV adjusting circuit CV Standard voltage for VC SV Standard voltage for CV and CV output EE adjustment l 1 For adjusting CV SV output and direct EE 2 For adjusting direct EE output pin No 69 SATT 8v ADJ AVERAGE 6V LJ Rioa RVICS 27K ek CV SV EE a
10. for adjusting lock voltage RV110 EE adjusting variable resistor For adjusting EE RV111 Head amplifier offset adjusting variable resistor For adjusting offset of the head amplifier Thyristors Q904 strobe flashing thyristor 2 9 LEDs 1 P101 BC SELF LED Functions as a mark in the BC and SELF modes 2 P102 MEMO LEO Functions as a mark in the MEMO and MEMO HOLD mode 3 P103 LAMP Lights for 10 seconds for illuminating the LCD 2 10 Control Magnets 1 RY101 MGI The releasing claw is disengaged by repulsive force of a combination of magnets MG1 is energized for unlocking the shutter 2 RY102 MG2 Controls the end shutter blind to determine exposure time 2 11 Connectors 1 J101 Rubber connector For transmitting output signal from LCD D to the LCD 2 J102 Hot shoe For connecting the strobe to the camera and signal line 3 J103 5 pin connector For connecting the strobe to the camera and signal line 2 12 Crystal Oscillator o 02101 Functions as a standard clock for LCD for the LCDD PCV and regeneration time 2 13 LCD o LD101 Liquid crystal display For displaying data processed by the CPU 2 14 PCV o SP101 PCV Sounds for warning 3 Description of Electric Circuits 3 1 CPU IC101 LU55211 is combined with the bipolar IC 1R3011 and LCD driver LH5070 to compose CMOS LSi for controlling the mechanisms of the camera LCD and other indicators Features of the camera u
11. made conductive and grounded by a certain the photographing operation i 1 32 e Circuit for indication and light measurement average light measurement and spot light measurement Block diagram Vref1 8 V Description of block diagram This block diagram shows the object brightness detector circuit for indication within the view finder corresponding to CdS of Model OM 2 Light is measured in the average mode or spot mode for indication Brightness measured in the average mode is indicated for photographing in the direct mode whereas brightness measured in the spot mode is indicated for photographing in the spot measurement exposure mode In the spot measurement exposure mode film is exposed for the time set with the SPOT switch According to mode selection A is set for direct light measurement spot light measurement or average light measurement and the SPD is selected by a command from the CPU Though photoelectromotive force of the SPD reaches scores of thousand as high at high bright ness such large variation of SPD output is reduced to a low level detected by A and fed into the bipolar IC 1 A constant current determined by R1 and standard voltage Vref 1 8V flows to R3 2 The constant current flowing through R3 cir culates to temperature campensating diode D1 Since D1 composes a negative feedback circuit potential is equal at the input and input terminals of A4 Therefore A
12. output No 16 BV output terminal Connected to BVIN of the bipolar IC through a filter for absorbing noise 2 Power ON compensation No 12 Limiter connected to the limiter output terminal No 1 of the bipolar IC 3 Integral output No 10 Integral output terminal for direct light measurement Provides integral output taking Vref 1 8 1 V as standard after Trg 1 is turned from L of H 4 Temerature compensating resistor No 9 BV termperature compensating resistor BV output is enhanced when this resistor has higher value and vice versa 5 Phase compensating capacitors No 3 and No 4 Adopted for preventing outputs Nos 10 16 and 18 from oscillating compensating 2 resistor Temperature Trigger signal Standard voltage input Log compression output A SPD anode SPD cathode common integral output NC Power ON compensator Power supply 3 4 LCD Driver 10104 is a liquid crystal cell driving element manufactured by CMOS silicon gate process it prepares an indication voltage twice as high as the power supply voltage by an internal booster and drives the liquid crystal cell at 1 3 bias and 1 3 duty It is equipped with 3 back plate terminals and 41 segment termi nals and capable of driving 123 segments max c System configuration CL LC SD 7mm Back plate terminais Hi Hi Hs Segment signals Si S o Description of system 1 Data transfer to C104 is
13. performed with serial transfer clock CL synchronous signal LC and serial data SD 2 At LC 0 the IC is set in standby con dition 3 At LC 1 data are entered upon recep tion of clock CL 4 Voltage is increased to 6V by the boosting capacitor etc C boosting capacitor 1 35 5 The standard voltage for driving the LCD is prepared by dividing the boosted volt age by resistor r 6 Arranged in IC104 is a RAM for storing segment and back plate indication data 7 1 bit of the RAM corresponds to 1 seg ment on the LCD 8 Addresses and data are set in the RAM by external serial data 9 The address is increased automatically by setting data into the RAM o LCD display ey Back H 1 pare Pobainiaie 6368 Segment The LCD display has segments in 41 horizon tal rows and back plates in 3 vertical rows Voltages at three stages of 2 4 and 6V ob tained by dividing the boosted voltage are inputted into the segments and back piates o Ignition of LCO display 1 A voltage of 2 4 or GV is inputted to a horizontal segment to be ignited and a vertical back plate respectively 2 Voltage is inputted so as to produce a voltage difference of at least 4V between the vertical and horizontal directions 3 Segments having voltage difference of at least 4V between the vertical and horizon tal directions are ignited When 2V is inputted to a horizontal segment and 6V is inputted to a vertica
14. spot light measurement When F No is changed shutter speed is varied in correspond ence to EV value and becomes equal to the exposure time in the SPOT mode When correction is modified exposure time is set at a level corresponding to EV value in the SPOT mode Shutter speed is varied Misoperation to result in over exposure Since exposure degree is determined based on the light intensity reduced by the preset over exposure results in to a degree corresponding to the number of steps from open to stop down position NOTE Exposure degree is unaffected in light measurement other than the SPOT mode direct light measure ment Use 50 mm F1 4 lens The shutter is opened for about 4 minutes by releasing it in the dark at ASA 100 F1 4 and spot F16 The camera is controlled by the microcomputer so that exposure time determined at F1 4 in the SPOT mode is set at O EV at F16 i Since light measurement in the SPOT mode at F16 cannot determine brightness accurately in the dark the shutter is not opened for 4 minutes Recodata Back 1 and 2 are incompatible with Model OM 4 250 film back is compatible if partially modified POL filter is unusable in the multi spot mode Model OM 4 is designed for dioptric control within a range of 1 to 3 0 When a lens deviating from this range is com bined with Model OM 4 diopter should be adjusted by using an eye cup 2 2
15. 2 2 Howisdiopter lens 5 usable ccc cee eee ht h nnn 2 2 I II INFORMATION OF SHUTTER Question Shutter is closed by selecting MANU AL mode while shutter is opened in AUTO mode and shutter is locked upon depressing shutter button in MANUAL mode Answer Mode change is inhibited during photographing operation When it is desired to close shutter while it is opened in AUTO mode select the B check mode before closing the shutter This phenomenon occurs in the products manufactured at the initial stage August to October but is no sign of a trouble In case of the products manufactured after October shutter is not closed and AUTO operation continues even when MANUAL mode is selected while shutter is opened in the AUTO mode INFORMATION ON USE OF STROBE Lamp flickers in operation with T series strobe but OVER indicated within viewfinder Exposure is apparently controlled to the correct level in TTL AUTO mode but OVER is indicated within view finder in operation with T series strobe filmy surface paper loaded How many strobe can be attached simultaneously Strobe usable at mechanical shutter time without battery Strobe flashing synchronized at manual time of 1 125 1 2000 Indication within the viewfinder reliable Change F No or photographing distance When T series strobe is deenergized during flashing it flickers the lamp as indication of strobe light control At short photographing d
16. 4 provides an output voltage equal to voltage drop of Vref D1 1 33 ASD 3 Connected to the input stage of A2 are SPOT SPD and average light measurement SPD Either of the SPDs is used according to select signal A S or D for A2 4 Let us now assume that the average light measurement SPD is selected The photocur rent flowing through this SPD circulates through the compression diode D2 into the output stage of Ad D2 is used for converting the photocurrent varying at a ratio of 1 scores of thousand into a voltage having a low variation ratio 5 A2 is a buffer amplifier having a gain level of 1 and potential is the same between the and terminals at the output stage 6 The input voltage to the terminal of A2 is equal to voltage drop Vref D1 whereas input voltage to terminal is equal to voltage drop Vref D1 voltage drop due to photocurrent from D2 Therefore A2 detects voltage drop sue to the photocurrent from D2 and provides BV output SPD output is obtained in this way 7 D2 is a silicon diode having a certain tem perature coefficient which is cancelled by connecting D1 and D2 to each other For this reason D1 is called temperature compensat ing diode e Functions of IO ports of head amplifier Power supply Phase compensating C gt Phase compensating C S SPD Anode SPD Cathode Functions of main terminals 1 Log compression
17. 5 aaup i 306105 IR 4 5 MA 1 00 Army VU sate i my enhan weno Juann buibitu3 INS Lonuos ya 1902 Y JONN I8 JAO 290015 nm L Suey LOW E E io ann col aaup LOW ses cess ssag rosea tat ue M02102 UANI piepueis eng Md nI aberjoa SY Unit ahenjoa wsy pang man anv avs AA 9 oqe se UMOYS t 43 01u02 Ajddns Jamog vlt The bipolar 1C consists of the blocks shown below 3 2 Bipolar IC e Block diagram F 1341011002 Ajddns samod 2I 2810019 MM dem mmm ne meee ee A0 3 00 BOTT geessoccmeseoeot 1 29 AS ANDOWNV Peer tore Corr e Description of bipolar IC circuit 1 BC H detector circuit The power supply voltage is judged in three stages 1 At Vcc 2 75V the PCV sounds inter mittently and LED stays lit 2 At 2 75V gt Vcc gt 265V the PCV sounds intermittently and LED flickers 3 At Vcc lt 2 65V the PCV stops sounding and LED is entinguished The BC H circuit judges whether Vcc is higher or lower than 2 75V According to command from the CPU the judgement result is outputted to a termina No 38 and processed by the CPU According to the processing result the CPU judges whether battery OK or warning is to be indicated BC L detector circuit This circuit operates quite independently from the CPU for judging whether power supply voltage is higher or lower than 2 65V Whe
18. EE GE Shutter control Pd Power supply hoid moa 12 ms self 125 Pi o oi MG1 i o Capacitor voltage 23 t 3 for MG1 Por r E M Charging starts i 4 i E i Variable Judgment level pi NE l R Pod Integral voltage m Di Po oc Integral correction i signal Oc X contact mechanical signal LLILLL 148 Hil IV Z OTHERS CONTENTS INFORMATION OF SHUTTER 1 Shutter locked by selecting MANUAL mode while shutter is opened in AUTO mode 00 cece cece aen eO 21 INFORMATION ON USE OF STROBE 1 OVER indication within viewfinder with strobe flickering TC 2 1 2 OVER often indication within viewfinder in use of T series strobe 2 1 3 How many strobes can be attached simultaneously 0 eee eee cee eee 2 1 4 Strobe usable at mechanical shutter time 1 60 without battery Z1 5 Strobe flashing synchronized at manual time of 1 125 1 2000 Z1 INFORMATION ON SPOT LIGHT MEASUREMENT AND EXPOSURE 1 How is exposure affected by changing F No ASA and correction after spot light measurement csse lene nnns 22 2 How is exposure affected by using preset for spot light measurement 2 2 3 Shutter is not opened for 4 min in spot light measurement ce ee eee eee 2 2 OTHERS 1 AI OM system compatible HD Z
19. For reducing noise entering the HA mode selector signal C402 Bypass capacitor For reducing noise entering the HB power supply bias signal C404 Bypass capacitor For rgducing noise entering the power lines related to the CPU C901 Delay capacitor To make Q903 by reserving a delay time of 20 ms min when the CPU reset is released i21 26 27 2 7 10 11 2 8 C902 CPU reset capacitor For preyenting the CPU from being left in reset condition C903 Delay capacitor For reserving time after the main switch is turned ON on the CPU until the main switch is turned ON on the bipolar IC Variable Resistors RV 101 resistor Cooperates with R101 for adjusting regenera tion time Regeneration adjusting variable RV102 Trg adjusting variable resistor Cooperates with R102 for adjusting Trg RV103 OFFSET adjusting resistor For adjusting offset of the main comparator RV104 Iref adjusting variable resistor Cooperates with R103 for adjusting the standard voltage RV105 BV average adjusting variable resistor Cooperates with R104 for adjusting BV level RV106 BV SPOT adjusting variable resistor Cooperates with R105 for adjusting BV SPOT level RV107 TV AV adjusting variable resistor Cooperates with R106 for matching DAC entry levels between TV and AV RV108 DAC adjusting variable resistor For adjusting DAC to 18 V per stage at 25 C RV 109 Lock adjusting variable resistor Cooperates with R107
20. H LIST OF SPECIAL JIGS AND TOOLS Name of too Application Remarks 1 KC CE5648 For tightening Lever nut CE564800 Incompatible with the lever nut having a narrow slit which was manufactured at the initial production stage Lever nut wrench 2 KC CE5683 For tightening ASA Cover holder stopper ASA cover holder CE568300 wrench 3 OT1057 high frequency For adjusting variable resistor Machine tip of the high screwdriver frequency screwdriver with 4 file as shown below D Z D Ad 7 ND KP A A t 7 Depth of groove equal to Wie plate thickness t 0 5 mm H 1 DESCRIPTION OF MECHANISM CONTENTS Ih OUTLINE uos xax vo RIPE TERES SES RUE Odo UR oct aen uela DERE Ho I PHOTOGRAPHING MODES 20784 osese EVI P Ga anee eee eee tee Pes i 2 1 Classification of Photographing Modes 0 0 0c cece eee PUDOR 1 3 2 Application of Photographing Modes 0 0 0 ccc cee eh es 1 4 2 1 Auto Mod orase esa gia Ep EE SEE Ga an dee sly wk ea ee LR 1 4 2 2 Manual Mode veles I RE Wo igs dad ce va Gs see EAR ER l 6 23 BulbMode oere erur rura er y E EE A A I ERO E S 7 24 Battery Check Mode 20 085 Gu edie de Mieres eoe Des eod E wha pet en i 7 Ill DESCRIPTION OF MECHANISMS 0 00 ccc eee hn 1 7 1 Mechanical 1 60 Sec Mechanism llle sees Og Wale Araceli are aes 1 7 2 Electromagnetic Shutter Lock Mechanism 2 20 2 02 e ce eee ee eee l 8 3 Mechanism to Prevent Film Winding d
21. OBE mode of the AUTO mode 9 OVER mark This mark flickers when shutter speed indicated on the bargraph exc ecs 1 2000 sec in the AUTO mode 10 lt q mark at the lower stage This mark is displayed ta indicate shutter time of the auto strobe 1 60 sec when the strobe power supply is turned ON in the AUTO mode 11 Index IIL PISI This mark is displayed in A of the AUTO modes e Shutter time lamps 2000 1000 500 250 125 60 30 15 8 4 2 1 1 All the lamps light in the AUTO mode 2 Only one lamp corresponding to the selected TV value lights in the MANUAL mode Bargraph 1 Shutter time is displayed on a bargraph in the AUTO mode Shutter time of 1 to 1 2000 sec is dis played in 1 3 EV steps c in the AVERAGE DIRECT AUTO mode shutter time is calculated from light measurement value BV ASA value SV corrected value CV and aperture value AV and indicated by the bar c 4n the MEMO AUTO mode shutter time is calculated from MEMO set value ASA value SV corrected value CV and aperture value AV and indicated by the bar 2 In the MANUAL mode exposure level for the set shutter time TV is indicated by the bar 6 1 3 EV tb 5 EV is indicated in 1 3 EV steps c In the AVERAGE MANUAL mode exposure level is calculated from light measurement value BV shutter time TV ASA value SV corrected value CV and aperture value AV and indi cated by the bar
22. PCV A ra E a a 1 22 3 1 CPU eee esae eie Stee ee e b E Ha S PP os 1 22 32 Bipolar On 1 28 3 3 Head Amplifier IC 0 cece eee eene 1 32 34 LCD Driver cece cece IH Ihm ehem 1 35 me SAG Bireult Board cioe EXPE KR N Ea echa uae e eyes 1 36 3 6 External Circuit for iQ esee NEMPE 1 00 DESCRIPTION OF PHOTOGRAPHING OPERATIONS 02s eee ee ees 4 1 Difference between Light Measurement for Indication and Light Measurement for Exposure sisse n tnn n 1 43 1 1 Light Measurement for Indication seer n 6 6n T 1 43 1 2 Light Measurement for Actual Exposure isse ntn 1 43 1 3 Relationship between Light Measurement for Indication and Light Measurement for Exposure iiis n n n n 1 43 2 Sequence of Photographing Operations ccc cece hh hh nnn 1 44 3 Exposure Program Flow Chart ec rn 1 47 4 Indication amp Exposure Time Chart ciis tnn nn 1 48 I OUTLINE Though OM 4 is designed basically on the basis of the preceding Model PM 2 it can exhibit far higher performance and features the chief meris men tioned below 1 Spot light measurement is possible in both the auto and manual modes 2 Spot light measurement is possible at multiple points 3 Exposure values can be stored for a long time 4 HI LIGHT and SHADOW modes are prepared for photographing 5 The viewfinder adopts a liquid crystal cell assuring legible indications 6 The view finder is equipped with a dioptmetric corrector
23. SV and TV during multi point indication spot input value is shifted directly to a new point The dot indicating spot light measure ment value of brightness of object to be photographed is shifted while lighting the intermediate segments in the same manner as that for the bar indication e Flickering cycle The segments for flickering indication are switched in the cyctes shown below 1 Over exposure in the AUTO mode DNE RECS REV CUN NES OVER OFF 2 UNDER OVER indication in strobe mode OVER ON 3 Exposure correction ON NW unc a ep ee OFF 4 Memory hold ON aa E OFF Note Indication remains unchanged for a period of time after the main switch is turned ON tili lapse of 100 ms after completion of integration For this time the memory hold lamp stays lit and UNDER OVER lamp goes out if the OVER and MEMO lamps are flickering 3 LED indications 1 SELF and B check LEDs l 1 The B check LED flickers when power supply voltage is lower than the warning voltage level in the B CHECK mode N Power supply voltage c I RS EE NERONI ALIS re Gees higher than warning level OF F Power supply voltage ON Jl um lower than warning level OFF LL 2 The SELF LED flickers during operation of the self timer VU EN tere ees Rm 1 26 2 Strobe LED 1 The strobe LED lights upon completion of strobe charging CHARGE signal at L level while marks is indicated on the LED STROBE signal at H
24. When the main switch is turned ON in these modes film is exposed at the shutter speed indicated by the bar Once the shutter is operated the spot mode including HILIGHT CONTROL and SHADOW CONTROL and all the spot inputs are cleared and the camera is set in the average direct auto mode 4 Memory auto 1 Average direct auto memory When the main switch is turned ON with the memory set by turning ON the MEMO key in the average direct auto mode film is exposed in the average direct auto mode and the exposure value is stored in the memory The stored exposure value is stored for 60 minutes after the shutter is operated Then the memory is cleared and the camera is set in the average direct auto mode In the memory hold mode the bar indicates a shutter speed to be adopted as standard level based on BV brightness of object to be photographed VS ASA value AV aperture value and CV corrected exposure value When the main switch is turned ON in the memory hoid mode film is exposed at the shutter speed indicated by the bar 2 Spot auto memory o When the main switch is turned ON in each spot auto mode SPOT HILIGHT or SHADOW film is exposed at the shutter speed determined in the set mode and the exposure value is stored in the memory The stored exposure value is stored for 60 minutes after the shutter is operated Then the memory and spot mode are cleared and the camera is set in the average di
25. a bar c B spot measurement values can be stored at a time Old values are cleared to enter new values o n each spot mode brightness of object to be photographed is always measured at a spot and a shutter speed determined based on the measured value is indicated by a dot The average direct mode is kept even after When the main switch is turned ON in the spot mode film is exposed at t e shutter speed indicated by the var Once the shutter is operated the ssot mode and ali the spot input values are cleared and the camera is set in the average direct mode 3 Spot auto HILIGHT SHADOW CONTROL o In the spot auto mode photographing conditions are switched as follows 1 HILIGHT CONTROL mode is set up by turning ON the HILIGHT key in the SPOT SHADOW mode 2 SHADOW CONTROL mode is set up by turning ON the SHADOW key in the SPOT HILIGHT mode 3 SPOT AUTO mode is set up by turning ON the HILIGHT key in the HILIGHT CONTROL mode 4 SPOT AUTO mode is set up by turning ON the SHADOW key in the SHADOW CONTROL mode In the HILIGHT CONTROL or SHADOW CONTROL mode entry of the spot input and dot indication are the same as those in the SPOT mode In the HILIGHT CONTROL mode the bar indicates a shutter speed 2 EV higher than the maximum brightness of the spot input values In the SHADOW CONTROL mode the bar indicates a shutter speed 2 2 3 EV lower than the minimum brightness of the spot input values
26. amera is set in the BY mode or the shutter is set for mechanical time of 1 60 sec When this key is depressed the LAMP LED stays lit for 10 seconds 2 The LAMP key is effective every other time it is depressed SPOT key 1 This key is effective in the AUTO MAN UAL and SPOT modes It is used for entering SPOT input When it is depressed in the average direct light measurement mode the camera is set in the SPOT mode 2 8 SPOT inputs max can be stored at a time New data can be entered by dis carding the old inputs 31 The SPOT key is effective in both AUTO and MANUAL average light measurement modes Upon depressing the key the camera is set for spot light measurement mode HILIGHT key 1 This key is effective in the AUTO and MANUAL SPOT modes o When the key is depressed in the average spot or shadow control mode the camera is set in the HILIGHT CON TROL mode o When the key is depressed in the HI LIGHT CONTROL mode the camera is set in the SPOT AVERAGE mode 7 SHADOW key 1 This key is effective in the AUTO and MANUAL SPOT modes o When the key is depressed in the AVER AGE SPOT or HILIGHT CONTROL mode the camera is set in the SHADOW CONTROL mode o When the key is depressed in the SHADOW CONTROL mode the camera is set in the SPOT AVERAGE mode MEMO key 1 This key is effective in the AUTO AVERAGE DIRECT light measurement mode and SPOT mode When the key is depressed in either of these m
27. and LCD 1C104 and external circuits 1 Basic Operations for Indication within Viewfinder 1 1 Conception of Each Circuit External mechanism camera body poseen nm nd Hc G2 LED LAMP AUTO MANU MSW TrgSw XSW l of TON usi PTT Fd Fimm pni or Data input Output Head amplifier LcD PW e CcC P U m 5 LCD LCD Interface bipolar IC CL SD o Data from the external mechanism are collected into the CPU through the interface for arrangement and judgement whose results are outputted to the display section of the external mechanism c The interface bipolar IC is ear to transmit data from the external mechanism to the CPU and hands and feet to transmit judgement results from the CPU to the external mechanism The CPU is brain to arrange and judge the data trnasmitted from the CPU The head amplifier is eyes to allow the CPU to sense external brightness 1 10 1 2 Block Diagram External mechanism camera body aZ LCDPW LCDD j C C104 SD o Description of signals Head amplifier contro signal Trg 1 Limiter Bipolar control signal a LCDPW eLCD LC CL SD Var types of NT switches Head amplifier control signal Head amplifier 1C103 V H e MG ON 7 PR MG1 C charged x M d MG2 ON SW LEDsON Bipolar controf P U signal Bipolar IC re1d C102 Trgi limiter Vref BV integral output Used for switc
28. ast Ef PAT Bact II PAY aic auta Mii o 3Y Strobe circuit STROBIN L terminal flash control 1 When the strobe is energized the camera is switched to the strobe mode through the L terminal 2 When the strobe is charged up pin No 39 is set at L level The CPU detects the L level judges completing of the charging sets pin No 33 at H level and lights LED P104 Lighting upon completing of charging STROBIN L terminal flash control gt SYRT PNP flashing signal flashing circuit Signal for driving strobe flashing thyristor 1 When a Shutter speed of 1 60 or higher is indicated in the DIRECT AUTO STROBE mode pin No 50 is set at H level to prevent the strobe from flashing 2 When a shutter speed lower than 1 60 is indicated and the X switch is turned ON pin No 50 is set at L level Q101 is made conductive C103 discharges through C102 R109 camera body Q101 and R110 and the thyristor is made conduc tive to flash the strobe 3 When the strobe flashes current from the L terminal stops and pin No 40 of the bipolar Cis set at L level The CPU detect the L level and knows the flashing of the strobe 4 When the main switch is turned OFF after completing exposure pin No 50 of the bipolar IC is set at H level Q101 is made non conductive and C103 is charged through body R109 C103 R111 and R111 Flashing circuit o TTL out TTL output When a shutter speed of 1 60 or lower
29. ceives a new input during display it restarts display for another 2 minutes Stop of display 1 When 2 minutes lapses after start of dis play 2 When the camera is set in the BU mode 3 When the shutter is set for mechanical 1 60 sec Note When the LCD display is stopped in the SPOT or MEMO mode the mode set ting is cleared automatically Display patterns 1 r1 mark This mark is displayed when the STROBO signal is turned ON and erased when the signal is turned OFF in any mode 2 mark This mark flickers during exposure cor rection in the AUTO or MANUAL mode 3 MEMO mark This mark is displayed in the memory set condition and flickers in the memory hold condition in the AUTO mode 1 24 4 SPOT mark This mark is displayed in the SPOT mode SPOT AUTO SPOT MEMORY AUTO or SPOT MANUAL of the AUTO or MAN UAL mode 5 HILIGHT mark This mark is displayed in the HILIGHT CONTROL condition when the camera is set in the SPOT mode of the AUTO or MANUAL mode 6 SHADOW mark This mark is displayed in the SHADOW CONTROL condition while the camera is set in the SPOT mode of the AUTO or MANUAL mode 7 UNDER mark This mark flickers for 2 seconds after completing photographing operation if exposure is insufficient in photographing in the STROBE mode of the AUTT mode 8 OVER mark This mark flickers for 2 seconds after completing photographing operation if exposure is excessive in 1 STR
30. d other LEDs are extinguished 2 Upon completing charging of C902 the reset pulse is switched from L to H level Q901 is made non conductive accordingly 1 36 BATT ST2080 3 When Q901 is made non conductive charging of C901 starts Until the voltage reaches a certain level Q902 Q903 LAMP MEMO and other LEDs are turned OFF 4 About 30 ms after C901 is charged up base voltage of Q902 is lowered to make it conductive Q902 Q903 LAMP MEMO and other LEDS are turned ON 5 When the reset switch is turned ON for changing mode Q901 is made conductive whereas Q902 Q903 LAMP MEMO and other LEDs are turned OFF 6 When the reset switch is turned OFF Q901 is made non conductive and charg ing of C901 starts For 30 ms after the reset switch is turned OFF tife LAMP MEMO and other LEDs are turned OFF Then the LEDs are lit Strobe misjudgment preventive circuit Description of circuit The strobe is flashed only at a shutter time of 1 60 or shorter in the direct auto strobe mode A time calculated based on BV value obtained by average light measurement is used for judging the shutter time The CPU may perform A D conversion of the BV value even after the main switch is turned ON When A D conversion of the BV value is per formed the head amplifier provides standard voltage of 1 8V It is switched to 1V when the main switch is turned ON n such a case the A D conversion is per
31. djusting circuit 5128 139x IC iz zz ia Ez4Az z54 AIS 921 i41 13 Direct integrating capacitor circuit Integrating capacitor far the direct id measurement mode At high ASA levels from 320 to 3200 C111 69 pF is selected At medium ASA levels from 40 to 250 C110 C111 398 pF are selected Atlow ASA levels from 6 to 30 C109 C110 1630 pF are selected Keone rm sme CREY T y RIIE l cce ex a rece ES C 162 LIMETER aecz INTESRATION LE 071 uT FuT UCUZ U INTESRATCR IN 3 t 8 LMETER L8 I BV NL IC IC 2 C1 41 C205 czigi 142 V DESCRIPTION OF PHOTOGRAPHING OPERATION Operations for photographing in the MANUAL AUTO SPOT and other modes will be described below with reference to the CPU bipolar IC head amplifier etc 1 Difference between Indication Light Measure ment and Exposure Light Measurement 1 1 Light Measurement for Indication 1 Average light measurement Photosensors A and SPD are used selec tively Exposure time is indicated based on direct light measurement The time is not used for actual exposure The light measurement indication corre sponds to that on the CdS meter in Model OM 2N The indication is provided for manual ex posure 2 Spot light measurement Photosensor elements S and SPD are used selectively Brightness is measured in the SPOT mode F
32. e TTL direct light measurement control When the strobe power source is turned OFF in the auto mode the camera is set in the average direct auto mode For 2 seconds after photographing in the strobe mode the following indications are provided 1 The UNDER LCD flickers with strobe LED extinguished if strobe light intensi ty is too low 2 The OVER LCD flickers with strobe LED extinguished if strobe light intensi ty is too high 3 The strobe LED flickers when light controi is proper 2 2 Manual Mode 1 Average manuai mode 0 Average of BV brightness of object to be photographed is measured standard exposure time is determined based on AV SV CV and TV and deviation from the standard level positive or nagative EV value is indicated by the bar In this case the standard exposure level is reached when tip of the bar is aligned with definite point mark I When the main switch is turned ON in this mode film is exposed at the set shutter speed The camera is kept in the average manual mode even after the shutter is released 2 Spot manual mode e The spot manual mode is set up by turning ON the SPOT key in the average manual mode In the spot manual mode BV brightness of object to be photographed is measured at a spot and entered The dot and bar indicate deviation from the standard ex posure level based on AV SV and TV The bar only indicates corrected value when exposure is c
33. e time BV Brightness of object Data entry into CPU Data are read by data transfer between CPU and bipolar iC CPU calculates AV TV SV CV and BV for indications within viewfinder CPU calculates AV TV SV CV and BV for indi cation with viewfinder Shutter button depressed Shutter released Mirror UP and main SW ON Interrupt is made from indication within viewfinder to exposure mode Proceeds to photographing mode Exposure condition 1 8 Exposure program Proceeds to selected mode programs respectively runs Regeneration time means 9 TTL DIRECT DIRECT AUTO an exposure time which is AVERAGE MANUAL subjected to A D cartversion and again to D A conversion 9 SPOT MANUAL SPOT AUTO 1 44 TTL 9 pinECT TTL DIRECT exposure mode 11 Delay ume Bipolar iC SE Ed 12 Tr z 10 oF ist shutter blind detected 145 End of integration 13 14 Judgment b AAA GE TERA MG2OFF 1 5 End 14 Wate for integral Output Matching with ASA sensitivity High speed limiter r AVERAGE MANUAL Regeneration SPOT MANUAL time SPOT AUTO esere 1st shutter blind starts Digital variable of indicated time transmitted to bipolar IC Bipolar IC Il lLDAGC 3 esse o Digital variable of indicated time converted into analog variable 2 jLesetongabon
34. educe noise to be mixed with the integral output C109 Integration capacitor Used in combination with C110 and C111 for functioning as an integration capacitor at low ASA level C110 Integration capacitor o Used in combination with C110 and C111 for functioning as an integration capacitor at medium ASA level C111 Integration capacitor Functions independently as an integration capacitor at high ASA level C112 phase compensation capacitor For adjusting frequency at amplifier gain level of 0 dB 13 14 15 16 17 18 19 20 21 22 23 24 25 C113 Bypass capacitor To reduce noise entering the standing voltage line 1 8 1 V switching output C114 Bypass capacitor For stabilizing standard voltage Output 1 8V C116 Strobe malfunction preventive capaci tor For preventing the strobe from flashing erroneously due to bound while the M switch is tumed OFF C201 MG1 capacitor For accumulating energy required to make MG1 repulsive C202 Surge absorbing capacitor For absorbing surge voltage in turning off MG2 C203 For preventing the strobe from flashing erroneously while MG2 is deenergized C301 Boosting capacitor For generating voltage 6 V required to drive the LCD C302 Boosting capacitor For generating voltage 6 V requifed to drive the LCD C303 Bypass capacitor For reducing noise entering the clock 32 768 kHz C401 Bypass capacitor
35. film switch SW107 ex SW108 SWwW1089 SW110 SW112 SW111 gs ete n ric To rear cover switch 17 U switch rear cover switch Turned ON and OFF to detect conditions af the rear cover U switch pA A To motor drive switch 1 37 18 SF switch film switch 9 Turned ON and OFF to detect film loaded conditions SF switch 10 Switch contact 4 1 o To motor drive switch d 12 s Body ground 4 19 RK switch 2 Turned ON and OFF to transmit film rewind 1 ing ready signal to the motor drive RK switch 2 E T gt 3 2 3 Transistors 4 1 Q101 Thyristor drive transistor For transmitting a signal to gate of thyristor 5 to make it conductive and flash the strobe 2 Q102 TTL control thyristor For TTL control of T Series strobe 2 5 3 Q103 CPU interrupt transistor 1 To set the INTA terminal of the CPU at the L lever to make an interrupt 4 Q104 MEMO LED drive transistor 2 Functions as a switch for MEMO LED ON OFF 5 Q105 LAMP drive transistor 3 Functions as a switch for LAMP ON OFF 6 Q201 MG drive transistor Functions as a switch for MG1 ON OFF 4 7 Q202 MG2 drive transistor Functions as a switch for MG2 ON OFF 8 Q301 LCD driver transistor For controlling power to LCD D according to signal from the CPU 1 18 Q401 BC SELF LED drive transistor Functions as a switch for BC SELF LED ON OFF Q901 Reset transistor For dischargi
36. form ed taking 1V as standard thereby flashing the strobe at a shutter speed higher than 1 60 This circuit prevents such erroneous flashing of the strobe The bipolar IC main switch is turned ON upon lapse of 2 to 3 ms after the CPU main switch is turned ON and turned OFF within 0 4 ms mzmzmz 1103 1 37 0904 Bipola MS 1 When the main switch is turndd ON charging of C903 is started and C904 is made non conductive After charging for 2 to 3 ms Q904 is made conductive and the bipolar IC main switch is turned ON 2 When the main switch is turned OFF C904 discharges Upon lapse of about 0 4 ms Q904 is made non conductive 3 6 External Circuits for IC 1 Mode switch and key input 1 MANUAL mode When pin No 19 is connected to pin No 13 on the CPU it is energized and runs to the MANUAL program 2 AUTO mode When pin No 19 is freed on the CPU it runs to the AUTO mode program 3 SPOT key SW107 When pin No 17 is connected to pin No 16 on the CPU it is energized and runs to the SPOT mode program 4 HILIGHT key SW108 When pin No 17 is connected to pin No 18 on the CPU it is energized and runs to the HILIGHT program 5 SHADOW key SW109 When pin No 17 is connected to pin No 14 on the CPU it is energized and runs to the SHADOW program 6 CLEAR key SW110 When pin No 18 is connected to pin No 16 on the CPU it is energized and runs to the CLEAR program i 7 DISP ke
37. g through data resistors and proportional to absolute temperature This circuit generates the standard current described above Direct ASA voltage circuit This circuit judges level of integral yoltage in the direct light measurement mode It switches leveis irregularly depending on CV value BV level converter circuit Data on brightness of object to be photo graphed is converted into an analog voltage by the head amplifier However the head amplifier However the head amplifier output cannot be subjected directly to A D conver sion and it is necessary to shift level about 300mVv Further the spot receiving area is narrower than the average area It is therefore necessary to compensate the difference between the average BV spot and spot BV of the head amplifier output even when brightness of objects to be photographed are on the similar level The BV level converter circuit has such a compensating function Trg adjusting circuit This circuit consists of CR and compartor and performs trigger adjustment with variable resistors Compartor This circuit compares integral voltage with judgment standard voltage in the direct and manual light measurement modes MG2 drive contro circuit MG2 is controlled not only by the compara tor described in item 14 above but by the high speed limiter signal outputted from the CPU and trigger data latch circuit described later The controls must be performed differently in the indi
38. he L terminal R901 Current limiting resistor To limit base current of Q901 R902 Current limiting resistor To limit collector current of Q901 R903 Current limiting resistor To limit collector current of Q902 R904 Discharging resistor For discharging C903 R905 Current limiting resistor For limiting base current of Q904 R906 Current limiting resistor For limiting base current of Q103 R907 Discharging resistor For discharging C902 R133 Carry resistor For adjusting and indications R201 Noise preventive resistor For preventing noise from the MSW input 2 6 1 10 11 12 Capacitors C101 Trg adjusting capacitor For adjusting mechanical advance or delay of the time from turning OFF the Trg switch to start of actual film exposure C102 Surge absorbing capacitor For absorbing noise other than the ON signal C103 Gate trigger capacitor For turning ON gate of thyristor to establish electrical continuity between its anode and cathode C104 Regeneration capacitor For creating shutter time 1 1 2000 in regeneration manual mode C105 AUTO RESET capacitor For resetting the CPU when the circuit is reset from the locked condition C106 Phase adjusting capacitor Performs fine adjustment of oscillating frequency and phase adjustment C107 Phase adjusting capacitor Performs fine adjustment of frequency and phase adjustment oscillation C108 Filter capacitor To r
39. hing among the average spot and direct light measure ment modes Integration start signal to the head amplifier Signal for restricting shutter time Signal for switching various circuit blocks used by the bipolar IC Answer signal from the bipolar IV to question from the CPU Power control line of LCDD The CPU turns ON and OFF the power supply through this line for power saving Clock of LCDO Data processimg for indication on the PCD is per formed in synchronization with this clock Frequency is set at 32 8 kHz Synchronous signal used for indication data transfer from the CPU Clock sianal for transferring indication data Serial data sign ls used directly as indication data I1 1 3 Operating Sequence for Light Measuremtn Indication barn 0710 A a TEET Soy ray see we wwe es Bipolar IC ee o a Cee sewer een we v wo 1 Head IN amplifier pee i 3 c Operating sequence 1 CPU check for key mode The CPU checks for a depressed ON switch to m udge manual or auto mode The CPU emits a strobe signal to locate a depressed key switch and sets the camera in the mode corresponding to the depressed key switch This CPU starts in the set mode 2 CPU reads external data The CPU uses the bipolar IC control signal to turn ON the power supply only for the components to be used for photographing and poses questions to the components Answers to the questi
40. iagram Trz Ampiifier gt Direct output Description of block diagram combination determined by command from Ulike the integration system of Model OM 2 the CPU Only the grounded capacitors are integration system of Model OM 4 amplifies input charged capacitor charging voltage of the OP amplifier to 3 When the 1st shutter blind travels and Trg is operate the comparator of the biopolar IC turned ON integration is started C C and C are integrating capacitors which are When Trg is turned OFF S and S are turned used selectively depending on ASA level since OFF and the capacitors are chaged with Model OM 4 has a wjde dynamic range of ASAG to photocurrent from the SPD 3200 4 The charging voltage is detected by A and 1 When film is wound and shutter is released at outputted to the amplifier arranged at the next the initial stage the main switch S and S are stage turned ON 5 The amplified integra voltage is fed into the 2 When S and S are turned ON A is actuated comparator of the bipolar IC and compared and its output Vref standard voltage of 1V is with the ASA judgment voltage applied to of A Simultaneously the 6 When the correct exposure level is reached the capacitors combination of C C and or C comparator of the bipolar IC is inverted the are charged magnet is deenergized the 2nd shutter blind Depending on ASA value C C and or C are Starts and the shutter is closed to complete
41. ilm is actually exposed for the indicated time Indication is provided for exposure in the manual spot mode 1 3 Relationship between Light Measurement for Indication and Light Measurement for Exposure Lught measurement for indication Indication within viewfinder Average tight measurement Indication within viewfinder Light measurement for exposure DIRECT AUTO SPOT AUTO SPOT MANUAL 1 2 Light Measurement for Actual exposure 1 Direct light measurement called AVERAGE DIRECT AUTO mode Photosensors A and SPD are used selec tively Brightness is measured in the AVERAGE DIRECT mode Film is exposed actually in the indicated time 2 SPOT AUTO light measurement SPOT AUTO Measured brightness is stored into memory Film is exposed actually in the indicated time 31 MANUAL AVERAGE MANUAL Manual exposure time is indicated for average determined by light measurement for indication 4 SPOT MANUAL Spot exposure time in the MANUAL mode is determined by spot light measurement for indication AVERAGE DIRECT AUTO AVERAGE MANUAL 2 Sequence of Photographing Operations E AVERAGE DIRECT AUTO AVERAGE MANUAL 1 Mode selection m SPOT AUTO SPOT MANUAL 1 Indicator ON upon selecting a mode 2 AV TV CV SV and BV are read AV Aperture value TM Shutter time SV ASA value CV Corrected exposur
42. is indi cated immediately before shutter release and integral output does not exceed the judgment level in the DIRECT AUTO STROBE mode pin No 48 is set at H level and does not prevent the strobe from flashing When the output exceeds the judgment level pin No 48 is set at L level to prevent the strobe from flashing 140 c TTL out PNP 5 A PNP transistor Mor creating TTL signal When pin No 48 is set at H level pin No 49 is set at L level and Q102 is made conductive to apply voltage of H levei to the strobe TT Lout T T Lout TTL output PNP 4 Trigger adjusting circuit The trigger switch is turned on at the initial stage When the shutter is released the trigger switch is turned OFF and integration start signal is fed to pin No 55 of the bipolar I However C101 serves to apply the voltage to pin No 55 to prevent integrating operation from starting even after the trigger switch is turned OFF Upon completing charging of C101 pin No 55 is deenergized to start the integrating operation Trigger timing can be created by varying charging time of C101 RV102 is arranged as the trigger timing adjusting resistor Trigger adjusting circuit RC RvC2 Cc OcifV MG2 drive circuit When the comparator circuit of the bipolar IC is inverted at the correct exposure level pin No 57 is set at H level Q202 is made conduc tive and MGZ2 is energized to elese the 2nd shutter blind MG2 drive
43. istance however correct exposure may not be obtained by stopping flashing in such a case OVER is indicated within the viewfinder _ It is suggested to answer that the conflicting indications are due to the high performance of the camera Filmy surface paper having reflectance higher than that of film is apt to cause OVER t6 be indicated Use paper having reflectance similar to that of film should be used fot demon stration Nine strobes can be attached simultaneously by using the direct contact TTL auto synchro socket and TTL auto multi connector Unusable l Since the strobe is flashed with the thyristor it oannot be used without battery The strobe flashes at all the manual times However note that it is not synchronized as 1 125 1 2000 in the AUTO mode the strobe flashes at the brightness corresponding to 1 60 sec or longer It does not flash at the brightness corresponding to longer exposure times 24 II INFORMATION OF SPOT LIGHT MEASUREMENT AND EXPOSURE Question 1 How is exposure affected by chang ing F No ASA and correction after spot light measurement 2 How is exposure affected by using present in spot light measurement 3 Shutter is not opened for 4 min in spot light measurement IV OTHERS 1 AIL OM systems compatible 2 How is diopter lens 5 usable Answer When F No ASA and or correction is modified shutter spe d is varied correspondingly to EV value in the
44. l back plate for example the segment is ignited When 2V and 4V are inputted however the seg ment is not ignited Segment igniting sequence 1 The CPU selects a segment to be ignited depending on conditions for operating the camera 2 A combination of vertical and horizontal voltages is calculated to ignite the segment of interest 3 The address of the segment to be ignited voltage for the vertical back piate and voltage for the horizontal segment are transmitted as serial data from the CPU to 1C104 LCD driver 3 5 RS Circuit Board o Reset circuit 4 1C104 LCD driver stores the data in its internal RAM 5 Simultaneously segment of the LCD dis play is selected and ignited Crd C02 RESE SeCOpr e a esc Aa to a Sd Description of cirucit This circuit is adopted for preventing the cir cuits from becoming inoperative when the CPU is set in ACL condition where ail the LEDs and lamps are lit current consumption increases and the mirror lock is actuated While the CPU is reset or for 30 ms after the CPU is released from the reset condition the LEDs LAMP MEMO BATT and STROBE are deenergized C902 is a reset pulse width limiter and C901 is used for deenergizing the LEDs by reserving a delay time of at least 30 ms 1 When the CPU is reset Q901 is made con ductive for the time r quired to charge C902 Q902 is made non conductive Q903 is made non conductive the LAMP MEMO an
45. le with a power supply of 3V Therefore direct light measurement capaci tors and judgement levels are simultaneously switched at three stages of low ASA medium ASA and high ASA The wide dynamic r nge and high ASA judgment level makes Model OM 4 highly resistant to noise The C value switching circuit selects judgment levels and integrating capacitors according to commands emitted from the CPU depending on SV values read into the CPU DAC This is a D A converter circuit composed of 8 bits in an irregular format Generated at the output stage of the DAC are analog voltages corresponding to levels in the 8 input bits connected to the output ports of the CPU Analog data such as SV and CV are compared with the DAC output voltages by a comparator described later for converting the analog values into digital signals 9 MPX amp COMP This system performs A D conversion by consecutive comparison Data to be subject d to the A D conversion are SV CV TV AV and BV However these data cannot be converted simuitaneously and subjected to A D conversion on a time base as tommanded by the CPU MPX amp COMP selects one of these analog data as commanded by the CPU and compares it with the DAC output by a comparator A comparator is provided for each type of analog data 10 11 13 14 15 Data standard voltage circuit Each analog data generator circuit basically consists of a standard current flowin
46. level in all the modes 2 The strobe LED goes out 2 sec after completing photographing in the strobe mode It flickers when light control is proper after flashing in the AUTO mode s Jn wee eo 3 MEMO LED 1 The MEMO LED flickers in the memory set condition i in the AUTO mode ON Memory set f OFF KEIN PERENNE CE EEE 2 The MEMO LED flickers in the memory hold condition in the AUTO mode 6 N j 4 LAMP LED indicator illuminator LED This LED stays lit for 10 seconds when the LAMP key is depressed during LCD indication in the AUTO or MANUAL mode The LAMP key is inoperative while the LAMP LED stays lit When the LCD indication stops in lit condition of the LAMP LED it is also extinguished UE cec NNNM OFF 1 LAMP KEY ON When the miain switch is turned ON while the LAMP LED stays lit it is extinguished and kept so even after completion of photographing M27 4 PCV Output 1 Key input valid The PCV sounds when CLEAR SPOT HILIGHT SHADOW MEMO or key input is entered ON CF NEUEN 2 Self timer actuation time ON E ge a Ts m a de Lotes 3 Battery check time 1 Battery voltage higher than warning level A i ea iL t t DAT SH ON BAT SW OFF 2 Battery voltage lower than warning level 4 Shutter time too long in AUTO mode REL 1 28 D unz aaup f Q31 413S 98 4 15021000 200 uoneiaus03y ti ATNI 35 423 reno 10210
47. n pin No 20 is connected to pin No 24 on the CPU it is energized and runs to the LAMP program The CPU set pin No 32 at H level and lights P103 for 10 seconds SW104SW105SW106 RS circuit board l MG1 drive circuit When power supply voltage exceeds the lock level or approx 15 ms elapses after the main switch is turned ON pin No 61 is set at L level and Q201 i made conductive When Q201 is made conductive C201 dis charges and MG1 is energized The shutter is not locked C201 is charged with a constant current of about 4 mA for 10 ms after Zempietiny photographing operation When power supply voltage is lower than the lock level pin No 61 is set at H level MG1 is deenergized and the shutter is locked MG1 drive circuit Regeneration EE adjusting regeneration C AUTO RESET circuits Regeneration C C104 This is an integrating capacitor for regenera tion time man al or spot Regeneration EE adjusting circuit For adjusting regeneration time AUTO RESET C105 1 39 A capacitor for oereating CPU RESET signal When power supply voltage becomes lower than the lock level the bipolar IC stops operating but starts operating again when battery voltage restores to about 2 9V It is therefore necessary to start the program aqain from the clear start This circuit outputs reset signal to the CPU for initializing Regeneration EE adjusting regeneration C and AUTO RESET circuit Y B
48. n power supply voltage is lower than 2 65V it forcibly turns OFF all the indicators other than those within the viewfinder stops power from combination magnet MG1 and locks the shutter to prevent the camera from abnormal operation or indication regardless of the low CPU voltage BC HOLD circuit Even when power supply voltage becomes lower than 2 65V at a low temperature battery voltage is gradually restored to the required level as temperature rises The BC HOLD circuit is a power supply voltage judging circuit which applies reset pulse to the CPU and has a hytersis width for restart irig operations when battery voltage is restored to 2 90V or higher after it becomes lower than 2 65V to stop all the functions of the circuits Restoration voltage is set at approx 2 90V Standard voltage generator circuit This circuit generates two voltages of 1 8V and 1V Battery check is performed by com paring power supply voltage with thesa voltages 1 30 5 Oecorder This circuit decodes digital signals transmitted from the CPU and generates control signals for each block l AV SV CV TV circuit This circuit generates analog outputs as aperture data AV ASA data SV exposure correction data CV and manual time data TV C value switching circuit Since Model OM 4 has a wide dynamic range of ASA 6 to 3200 integral voitage judgement level in the direct light measurement mode is too high for the ordinary method and impossib
49. ng capacitor C901 Q902 Reset transistor For turning OFF Q903 at GO H Q903 Reset transistor For supplying power to LED and lamp Q904 MS transistor For turning ON bipolar MS input Diodes D101 For isolating the data back side from the camera side 0102 Protective diode Protective means to prevent the batteries from setting in the reverse direction D701 Protective diode For protecting the L terminal D901 Noise preventive diode For preventing noise from the MS input D902 Noise preventive diode For preventing noise from the MS input Resistors R101 Regeneration adjusting resistor Cooperates with RV101 for adjusting re generation time R102 Trg adjusting resistor l Cooperates with C101 to prepare delay time for triggering R103 Iref adjusting resistor For matching RV104 with the reference current in the data contro current generator circuit of bipolar IC R104 BV adjusting resistor Cooperates with RV105 for adjusting BV level 10 11 12 13 14 15 16 177 18 19 R105 BV SPOT adjusting resistor Cooperates with RV 106 for adjusting BV spot level R106 TV AV adjusting resistor Cooperates with RV107 for matching DAC entry levels between TV and AV R107 Lock adjusting resistor Cooperates with RV109 for adjusting lock voltage 2 65V for locking and 2 90V for unlocking R108 Lock adjusting resistor Cooperates with RV109 for adjusting lock voltage
50. o light measurement indication but strobe mark only is displayed MG1 and MG2 are inoperative for control even when the main switch is turned ON in this mode l The battery check function is operative in this mode 2 4 Battery Check Mode The battery check function is operative in all the modes so long as the battery check switch BAT SW is kept ON l o However the function is inoperative only during shutter release operation o When power supply voltage exceeds the warning level 2 75 0 05V The battery check LED lights and PCV sounds When power supply voltage is below the warning level Teh battery check LED flickers and PCV sounds intermittently o Power supply voltage is judged based on current consumed while the battery check LED stays lit o When the battery voltage is blow the lock level 2 65 0 05V the LED and PCV are inoperative The PCV can be stopped by manipulating the self timer level Il DESCRIPTION OF MECHANISM 1 Mechanical 1 650 Sec Mechanism When the SD is set at 1 60 sec the BU Lever 24175700 moves rightward Then K Lever 2 CE504800 is brought into contact with K Cam CE504100 of gear A Simultaneously R Claw 2 CE504700 is engaged with convexity D of Gear plate B CE500900 to stop rotation of gear B Further the bulb plate holds the R claw to prevent it from going to the convexity of gear plate B Part C When the 1st shutter blind is turned the K
51. ode the camera is set in the MEMO mode 2 The MEMO key is ineffective once the memory is set CLEAR key 1 This key is effective in the AUTO and MANUAL modes except when the camera is set in the BU mode or strobe mode When the key is depressed the bar and spot inciations are erased and the camera is set in the AVERAGE DIRECT light measurement mode o In the AUTO mode SPOT MEMO and MEMO HOLD settings are cleared o n the MANUAL mode SPOT setting is cleared and the camera is set in the AVERAGE MANUAL mode 10 DISP key 1 This key is effective for starting indica tions on the LCD in each of the AUTO and MANUAL modes 2 When the LCD has already started indica tion display time 2 min is updated by depressing the DISP key 2 LCD Display function 1 The LCD displays light measurement and memory regeneration in the AUTO and MANUAL modes as well as OVER and UNDER in the STROBE mode e Start of display 1 When the mode switch is turned to AUTO or MANUAL 2 in the AUTO or MANUAL mode o When the STROBE signal is turned ON or OFF c When photographing operation com plates o When a valid key input CLEAR SPOT HILIGHT SHADOW or MEMO is received the LCD restarts when it receives a new input during display o When the DISP key is depressed Ist stage of the release button e Display time 1 Light measurement and memory regenera tion are displayed for 2 minutes 2 When the LCD re
52. ons are returned as a to the CPU In this way the CPU knows aperture value ASA sensitivity and so on 3 CPU displays the results The CPU makes judgements based on read data and indicates judged results on LCD and lights LEDs i12 In spot auto auto manual or memory auto mode X The regeneration time circuit of the bipolar IC is used Jh VEIT im HRP T iba cpu fEuERY Bipolar 1C D Head ampiifier o Operating sequence 1 The Trg switch is turned OFF when the 1st shutter blind travels 2 This switch operation is detected and an input signal is fed into the trigger adjusting circuit of the bipolar IC a delay time is reserved at this stage 3 The trigger adjusting circuit outputs Trg OFF signal to the CPU 4 The CPU calculates the shutter time set by the Trg OFF signal 5 Upon completing the calculation the CPU inverts the M comparator 6 Upon inversion of the M comparator MG2 is deenergized and the 2nd shutter blind traveis to complete the exposure 7 Simultaneously the CPU detects the completion of exposure and starts charging the capacitor for driving MG1 8 After the capacitor for driving MG1 is charged up the CPU returns to the initial program for indication 1 14 2 Description of Electric Parts 2 1 ICs UNE IC101 LU55211 H IC103 IR3010 1C104 LUS070 1 1C101 LU55211 CPU l Performs centralized processing of all types of data and con
53. orrected When the SPOT key is turned ON in the spot manual mode a new spot light measurement value is entered and the dot indicates an exposure level determined based on the new value paseo V the bar indicates an ex posure level determined based on an average of spot inputs at two or more points 8 spot inputs max can be stored at a time New data are entered while discarding the old data In each spot mode brightness of object to be photographed is always measured at a spot and the scanning dot indicates an exposure level determined based on the measured value When the main switch is turned ON in this mode film is exposed at the set shutter speed The camera is set in the average manua mode after the shutter is released 3 Spot manuai mode HILIGHT SHADOW CONTROL A in this spot manuai mode photograpning conditions are switched as follows 1 The HILIGHT CONTROL mode is set up by turning ON the HILIGHT key in the SPOT SHADOW mode 2 The SHADOW CONTROL mode is set up by turning ON the SHADOW key in the SPOT HILIGHT mode 3 The SPOT MANUAL mode is set up by turning ON the HILIGHT key in the HILIGHT CONTROL mcde 4 The SPOT MANUAL mode is set up by turning ON the SHADOW key in the SHADOW CONTROL mode In the HILIGHT CONTROL or SHADOW CONTROL mode entry of spot inputs and indication by the dot are the same as those in the SPOT MANUAL mode The dot indication does not vary In the HILIGHT
54. rect mode in the memory hold condition of the spot auto mode the conditions for the AVER AGE HILIGHT CONTROL and SHADOW CONTROL as well as indications are kept the same as those before turning ON the main switch in the memory hold condition the SPOT HIGH and SHADOW keys are ineffective A new key input is invalid so long as the memory is reset When the main swtich is tumed ON in the memory hold condition film is exposed at the shutter speed indicated by the bar Auto strobe c The strobe photographing mode is set up by turning ON the strobe power source in each auto mode When the strobe power source is turned ON ven in the spot auto memory set or hold condition it is cleared automatically and the camera is set in the averace direct auto mode in the auto strobe photographing mode the bar indicates a shutter speed determined based on average of BV brightness of Object to be photographed AV lsperture value and CV corrected exposure vaiue in the same manner as in the average direct auto mode When the main switch is turned ON while a shutter speed of 1 60 or lower is indicated the strobe is flashed and its light is subjected to TTL auto control Shutter speed is set at 1 60 sec in this condition When the main switch is turned ON while a shutter speed higher than 1 60 sec is displayed the strobe is not flashed and automatic film exposure to natural light is performed under th
55. rement value with the correct level MG1 drive circuit This circuit consists of a circuit for the capacitor for driving combination magnet MGI with a constant current and another circuit for discharging electric charges ac cumulated in this capacitor to MG1 in a moment LED drive circuit This circuit prevents the LEDs from lighting erroneously when power supply voltage becomes lower than the lock level 24 BC SELF LED drive circuit 26 PCV circuit This circuit drives the LED serving both for This circuit controls sounding of the PCV the battery check and self timer actuation it prepares PCV sounding frequency of 2 kHz 25 LCD control circuit and 4 kHz by dividing chiefly 32 768 kHz This is a gate circuit which prevent the LCD 27 Analog switch from providing erroneous indications due to Used for switching the standard voltage be malfunction of the CPU when power supply tween 1 8V and 1V voltage becomes lower than the lock level If forcibly turns OFF the LCD when power 28 MS CONT circuit supply voltage is lower than the lock level This circuit controls power supply for each block when the main switch is turned ON 3 3 Head Amplifier iC The head amplifier functions as an integration circuit in the direct light measurement mode it generates compression voltage average BV and compression voltage of spot brightness spot BV during indication and light measurement e Circuit for direct light measurement Block d
56. s operated with the memory set in position the exposure value is memorized for one hour then it is cleared and the camera is set in the average direct mode l 2 Average manua Average of BV is measured and bar 1s Uisplayed based sr AY SV and TV When tip of the bar is aionged with the difinite point mark exposure levei is set at standard Spot high light standard manua The entire indication is shifted depending or AV and TV Bar is dispiayed at a eve 2 Ev below maximum level Soot shadow standard manua The entire indication is shifted depending on AV and TV The bar is displayed 2 2 3 EV above minimum level otograpn g in manual moce Mode switch is set at MANUAL The entire indication is shfted depending on AV SV and TV When the bar indication is aligned with the definite point exposure level is set at standard The bar indication only varies depending on CV CV Corrected exposure value 5 as indicatec wne P604 charging current flows Average direct auto At a shutter speed higher than 1 60 sec average direct auto mode is set by natural hght strobe does not fiasni Average manual 3 is indicates when in strobe mode charging current flows Open turning ON the strobe power source X switch is turned ON strobe flashes at any TV INT is actuated to set up average direct Indications are the same as those in the average auto or average manual manua mode
57. sing LU55211 are des cribed below 1 Photographing inodes Average direct mode Manual mode Spot mode average high light control and shadow control Strobe mode Memory mode 2 Display items on LCO Shutter time OVER 1 2000 1 S Light measurement level 5 EV 61 3 EV manual mode 3 indicator LEDs Battery check LED Strobe LED Lamp LED Memory LED 4 PCV output Key input time Self timer actuation time Battery check time Shutter time too long in auto mode 1 Mode Switching and Key Inputs 1 Mode switching MANUAL The camera is set in the manual mode when the mode switch is set at MANUAL AUTO The camera is set in the auto mode when the mode switch is set at AUTO 2 SLEF switch 1 When the main switch is turned ON with the SELF switch set at ON preliminarily the self timer actuates and then the camera is set in a photographing mode Self time 12 sec except when the camera is set in the BU mode or the shutter is set for mechanical time of 1 60 sec 2 When the SELF switch is turned ON dur ing operation of the slef timer the camera is set in the photographing mode im mediately BAT switch 1 When the BAT switch is turned ON the camera is set in the battery check mode and power supply voltage is compared with the standard voltage 2 The battery check mode is cancelled by turning OFF the BAT switch LAMP key 1 This key is effective in the AUTO and MANUAL modes except when the c
58. sm to prevent film winding during exposure time dioptric correction mechanism and large legible liquid crystal display ll PHOTOGRAPHING MODES Model OM 4 is designed basically for four photographing modes auto mode manual mode strobe mode and spot mode 1 Classification of Photographic Modes Average light measurement automatic exposure average direct auto Spot automatic exposure Photographing Spot high light shadow standard auto in auto mode Average direct auto memory Memory auto Spot auto memory ES SS JN RL Release TV Shutter speed CL Clear AV Aperture value SV ASA value BV Brightness of object tobe photographed Average df BV is measured TV is indicated based on AV and SV and automatic exposure is performed by direct light measurement Average direct auto memory Photographing Memory auto Mode switch is Exposure value at shutter Spot auto memory setat AUTO telease time is stored in memory NEMO CL atter even number Ot HIGH SHADOVI Spot high light standard auto O70 ccm exposure operations M 2 EV above maximum level HIGH BV is measured in SPOT mode SHADOW TV is indicated based on AV and SV and exposure is pertormed at indicated TV TV is determined by simple averaging 2 2 3 EV below minimum level After the shutter is released in the spot multi point auto mode the camera is set in the average direct auto mode Once the shutter i
59. the same potential as that on the anode side of the head amplifier R123 Positive feedback resistor For forming a positive feedback loop which prevents leak current by maintaining the same potential as that on the anode side of the head amplifier R124 Filter resistor Cooperates with C108 to composed a low frequency filter R125 Bias resistor for temperature compensa tion diode To minimize drift from temperature of the offset circuit R126 For reducing ifnpedance by preliminary pulling down to prevent Q103 from operating erroneously due to noise R127 To minimize variation of impedance in the Trg 1 output R128 For compoensating insufficient output from the CV SV operation amplifier R129 For compensating insufficient output from the DAC operation amplifier R130 To erase blinking of about 3 segments in the bar indication R132 To prevent the strobe from flashing at its maximum speed 32 33 34 35 36 37 38 39 40 41 42 43 45 46 R301 R302 R303 and R304 Dividing resis tors To divide the LCD driving standard voltage for preparing bias voltage R305 TEST terminal pulling down resistor To reduce impedance of the TEST terminal for preventing the TEST mode from being set up by accident R306 To linearize rise waveform of LCD R307 To linearize fall waveform of LCD R401 Current limiting resistor To limit collector current of Q401 R701 To protect t
60. trols the camera through the bipolar IC 2 1C102 IR3011 Bipolar1C Functions as an interface between external data inputs and CPU 3 1C103 IR3010 Head amplifier iC Performs light measurement in the AUTO or MANUAL mode and integration in the AUTO mode and provides results to the bipolar IC 4 1C104 LCDD Indicates all types of data collectively on the LCD i15 2 2 Switches 1 SW101 Main switch Emits an interrupt signal to the contro ICs CPU and bipolar IC of the camera and also serves to supply power to a part of the bipolar IC SW101 To FPC Body ground Diaphragm lever Se Tube SW102 X switch For flashing the strobe It is turned ON immediately after the Ist shutter blind completes travelling and the shutter is fully opened 1 60 SW102 NS Body ground To TV circuit board SW103 Trigger switch For starting calculation of exposure time in the AUTO or MANUAL mode It is tumed ON when film is wound shutter is charged It is tumed OFF when the 1st shutter blind starts travelling for starting film exposure SW103 Body ground T pin a R To TV circuit board 4 SW104 Self timer switch When this switch is turned to the left position from the neutral position it functions as the self timer switch after shutter release When it is turned to the right position the PCV stops sounding SW104 NOMAL SELF aol SUN LED indicator window 5 SW105 Battery check switch
61. uring Exposure Time euasacssrecrse l 8 4 Dioptry Adjusting Mechanism 00 ce cece eH eme 9 IV DESCRIPTION OF ELECTRIC CIRCUITS 0 cece eee eee hears 1 10 1 Basic Operations for Indication within Veiwfinder and Film Exposure 1 10 1 1 Conception of Each Circuito 0 ee cc tee nen 1 10 1 23 Block Diagram 1 20 ccc cee ete cee aset heme 1 11 1 3 Operating Sequence for Indicating Light Measurement 505 1 12 1 4 Operating Sequence for Controlling Shutter Speed inv eerie tee eres 1 13 2 Description of Electric Parts 0 cece eee eee eee heh hn 1 15 DN NOS cr 1 15 2 25 Switehes vd ovo ices ave an RUE CUC eae EGET eget a ro MEN PENANG 1 16 2 3 Transistors pua kat Kad d a a eda s AR Na e eS Io RE OG QN am 1 18 24 iSc coo eu ae el pr SA Su ai MOX NOE 1 18 2 5 Resist f oc oos sve e Fel bees Fa ER eid ages CoG G neat 1 18 DG Capacitors accep cghcanedoketeuunre besos or yee EE EEAT V dais dS 1 20 2 7 Variable Resistors 6 eee e eee e eee e enn nome 1 21 2 8 Thyristors eese vai iau as quad EET eT re Dieseth 1 21 280 CEOS aaa xd aee EE a r DC S aE EEEE 1 22 2 10 Control Magnets iss eee eere e dea aS Ras es ne ona dn ma e 1 22 2 11 Connector ec anei uae kv Pace edes haw NAR Dar e or M 1 22 2 12 Crystal Oscillators 0 ccc ccc cece eee c eet ee een e wee enesnceseeees 1 22 2 13 LCDs uerai ro ba dibie rn Hales a nr bw ced alg ES EAR Se eG eon Reese 1 22 2 14
62. vidual modes i This circuit composes the high speed limiter signal output from the trigger data latch circuit and compartor output for driving MG2 1 31 16 17 18 19 20 21 22 23 Trg data latch circuit This circuit transmits pulses indicating ex posure time to the CPU Regeneration time circuit This circuit creates manual time Strobe flashing circuit The strobe is flashed at ful speed in the manual mode and only at 1 60 or lower speed in the auto mode This circuit determined whether or not the strobe is to be flashed and generates gate signal for triggering SCR when the strobe is to be flashed Light control circuit This circuit generates TTL contro signal Flash control circuit The strobe TTL control is performed when the power supply is turned ON for the strobe designed for use with Model OM 4 Further the LED lights in the viewfinder when the strobe is charged up These controls are performed by discriminat ing levels of the current flowing from the strobe to the L terminals and judging the signal from the discriminator circuit by the CPU The flash control circuit detects current levels on the two terminals Strobe OVER UNDER circuit Strobe OVER is judged when judgment level is 1 EV higher than the correct level whereas strobe UNDER is judged when judgment leve is 0 6 EV lower than the correct level The strobe OVER UNDER circuit compares integral of direct light measu
63. y SW111 When pin No 18 is connected to pin No 15 on the CPU it is energized and runs to the DISP program 8 MEMO key SW112 When pin No 18 is connected to pin No 14 on the CPU it is energized and runs to the MEMO program The CPU flickers P102 by applying H and L signals to terminal No 31 AUTO OMA NU x Sw12 su sant eS 1 u552111 sE 26 ee et aet Swi1O07T SPOT iC8 HIGH 109 SHAD 10 CLR tit DIS 112 MEYO RS circuit beard 9 SELF switch SW104 When pin No 20 is connected to pin No 26 on the CPU it is energized and runs to the SELF program After the shutter is released MG is kept deenergized During this while pulse sig nals are emitted from pins No 41 and No 52 of the bipolar IC to flicker LED P101 and sounds PCV SP101 12 seconds later pins No 41 and No 51 stop providing the output pin No 61 of the bipolar IC is set at L voltage MG1 is driven and the shutter starts exposure 10 Battery switch SW105 When pin No 20 is connected to pin No 25 on the CPU it is energized and runs to the battery check program The CPU transmits a battery check com mand to the bipolar IC The CPU judges the answer and gives a command to the bipolar IC to determine whether or not pulse signal is to be transmitted from it The bipolar IC provides pulse signal or not to pins No 41 and No 52 according to the command LED P101 and PCV SP101 are actuated 11 Lamp switch SW106 Whe

Olympus OM-4 Service Manual Part 4 of 4

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