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B. External Observations:

Shutter slow or open in "Auto Average."

Manual speeds normal.

"Spot-Auto" speeds normal

LCD normal

C. External Observations:

Shutter slow or open in "Manual,"
Shutter slow or open in "Spot Auto,"

"Auto" speeds normal

LCD normal.

Note: Be sure LCD indicates correct

"Manual" speed. If not, TV-VR is

dirty.

OLYMPUS OM-4, PAGE 16

Содержание OM-4

Страница 1: ...going to the viewfinder to the photodiodes on IC 103 A BV voltage changing 18mv Ev with light is output from pin 16 IC 103 to pin 7 IC 102 At the same time IC 102 watches aperture setting AV VR at pi...

Страница 2: ...e the equivalent ofexposure with a signal from pin 80 to pin 14 IC 103 Voltage on the integrator s output begins to increase at a rate proportional to light intensity at the film plane The same voltag...

Страница 3: ...ight ASA and aperture conditions then calculates an exposure If shutter speed is less than 1 60 the flash will be triggered during exposure Light from the flash is integrated by IC I03 the same as Aut...

Страница 4: ...ry check in the previous step there is a power circuit problem Test power consumption 4 Watch the viewfinder LCD as you change aperture ASA and scan different subject brightnesses The bar graph should...

Страница 5: ...Pins 16 and 17 Memory Yellow to Brown or Pins 18 and 14 Clear Yellow to Red or Pins 16 and 18 8 The circuit may be cleared by moving the Mode Switch to the battery check position 9 Take care to avoid...

Страница 6: ...o metering mode You can drive the circuit bonkers with random highs to pin 30 Pin 31 is output to Memory LED on Spot button Pin 32 is output to Q 105 to operate LCD backlight lamp Pin 33 is output to...

Страница 7: ...CPU Pins 21 and 22 are mode control from CPU Pins 56 55 IC 101 Pin 23 is signal from CPU to power LCD Pin 24 is power on signal from IC 101 Should go high when release is pressed one half stroke Pin 2...

Страница 8: ...Pin 60 is charge signal to C 201 for MG 1 Voltage will pulse high at release then fall to near zero to recharge C 201 Pin 61 is release signal to Q 201 for MG 1 Pulses low for release Pin 62 is B in...

Страница 9: ...ives under a circuit board between the prism and ASA resistor It is not easy to reach for tests but important inputs can be checked at ICs 101 and 102 Its output of course is the LCD Pin 1 is CLK inpu...

Страница 10: ...de Manual and Spot Auto speeds are normal LCD normal 1 A 1 B 2 A 2 B 2 C 3 A 3 B 4 A 4 B Shutter slow or open in Manual and Spot Average Auto Average speeds normal LCD normal Shutter fast or running t...

Страница 11: ...1 Power Circuit Malfunctions A External Observations No LCD No battery check No shutter operation except mechanical OLYMPUS OM 4 PAGE 11...

Страница 12: ...B External Observations Batteries run down quickly Shutter functions may or may not be normal LCD may or may not function OLYMPUS OM 4 PAGE 12...

Страница 13: ...or under Spot Auto speeds slow Auto speeds slow or normal Manual speeds normal First check bar graph response to light ASA and AV changes to isolate problem Follow the same pro cedure as 2 A but look...

Страница 14: ...onnects across pins 7 and 8 IC 102 Value is 0 015 MF 2 Check if bar graph is stable in BC mode If so check R 130 near IC 101 3 Check for dirty wipers on AV VR and SV VR 3 Release Malfunctions A Extern...

Страница 15: ...Shutter releases once then will not release again until circuit is reset LCD normal 4 Shutter Malfunctions A External Observations Shutter stays open in Auto and Manual Mechanical speeds OK LCD norma...

Страница 16: ...ual speeds normal Spot Auto speeds normal LCD normal C External Observations Shutter slow or open in Manual Shutter slow or open in Spot Auto Auto speeds normal LCD normal Note Be sure LCD indicates c...

Страница 17: ...D External Observations Shutter fast or runs through Auto and Manual LCD is normal Mechanical operation is normal OLYMPUS OM 4 PAGE 17...

Страница 18: ...mal LCD is normal G External Observations Manual speeds not correct or won t respond to adjustment Auto mode speeds OKt 1 Check each Manual speed with LCD If LCD does not correspond to speed dial TV V...

Страница 19: ...5 Display Malfunctions A External Observations No LCD or weak or erratic Shutter functions normal Exposure is normal OLYMPUS OM 4 PAGE 19...

Страница 20: ...isplays wrong characters for mode Shutter function appears to be normal Look for poor solder connections at wires to Display Board 6 Flash Malfunctions A External Observations Flash will not fire Flas...

Страница 21: ...r not working Self timer function is normal 1 For LED apply B to pin 41 IC ID2 through 1000 ohm probe If LED flashes IC 102 may be defective If no LED check B to LED Black wire from TP 1 Also Q 401 an...

Страница 22: ...OLYMPUS OM 4 PAGE 22...

Страница 23: ...OLYMPUS OM 4 OLYMPUS OM 4 PAGE 23...

Страница 24: ...s a violation of the law Willful violations of the been taken in the preparation of this manual the publisher Copyright Law of the United States can result in civil assumes no responsibility for any e...

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