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2.
Auto-exposure erratic, shutter sometimes delivers mechanical
speed only.
Memory time lag
Chattering in magnet switch
Check the timing between the magnet switch and the memory switch
by plugging the modified circuit board (Fig. 7) into the mirror-
box connector I100. Power the special circuit board with a 6V DC
power supply. Then measure across the switch with an
oscilloscope as you release the mirror-box. You should measure a
time lag of 10-12ms between the moment the memory switch opens
and the moment the magnet switch closes. Adjust the time lag by
reforming the long blade of the magnet switch at the point
indicated in Fig. 5. The oscilloscope test also allows you to
see chattering in the magnet switch.
3.
Shutter delivers only fastest speed at auto, LEDs operate OK
Electromagnet
Check the continuity of the electromagnet coil between the blue
wire and brown wire at the front-plate circuit baord. You should
measure approximately 350 Ohms.
Magnet switch SWg
The magnet switch (Fig. 5) should close as the diaphragm-closing
lever starts to move down. You should them measure direct
continuity between the orange wire and the black wire (Fig. 7).
To check the magnet switch without removing the mirror-box, you
can use the modified circuit board shown in Fig. 7. From the top
of the camera, proceed with the disassembly far enough to lift
out the memory circuit baord. Check for direct continuity
between the orange-wire connection anf the black-wire connection
with the shutter held open on Bulb. No continuity: Magnet switch
is not closing.
4.
Power winder transports film during exposure
Winder sync switch
Check the continuity between the green-wire poser winder
terminal (Fig. 2) and ground. You should measure direct
continuity with the shutter open, indicating that the winder
sync switch (Fig. 5) has closed.
Malfunctions resulting from poor solder connections or poor poor
contact at mirror-box connectio I100
1. Violet - LEDs work, shutter hangs open or delivers slow speed
2. Orange - LEDs work but continue to charge with mirror up
Shutter delivers mechanical action only
3. Violet - LEDs work, shutter hangs open or delivers slow speed
23900
Page 13 of 15
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