Service Manual

The shutter sectors remain open at "B" setting even after pressure on the shutter release
button is released. This is attributed to the fact that the electric potential of the charging
condenser (C1) fails to rise because either the shutter speed resistor (VR-2) or the trigger
switch (SW-5) does not reset to the "OFF" position.
4.3.2.1 Failure of the shutter resistor (VR-2) to provide normal
resistance.
Check the resistance of the VR-2 according to the procedure outlined in 4.3.1.3. If no
continutiy is determined, it is an indication of a disconnection of the yellow or pink lead
wire or poor contact of the contact pieces of the VR-2.
4.3.2.2 The trigger switch (SW-5) fails to turn off.
Remove the gray lead wire from the shutter printed wiring panel and undertake continuity
test by setting the shutter to the "B" setting.
This test must be undertaken by setting the shutter control to either "B" or slow shutter
speed setting, because the SW-5 sets to "OFF" position only over the duration the shutter
remains open.
If it fails to set to "OFF" position, it is an indication of a malfunction of the SW-5;
therefore, make proper adjustment of its contact pieces. Because the position at which the
SW-5 sets to "OFF" position directly affects the exposure time (particularly in case of
high shutter speeds), the precise position where it turns off must be checked meticulously
after adjusting the contact pieces.
4.3.2.3 Malfunction of the amplifier unit.
If the shutter speed resistor and trigger switch are found to be in order, the cause can be
attributed to malfunction of the transistors, causing the shutter to remain open because no
electric current flows to the electro-magnet even if charging of the condenser (C1) takes
place. To repair, make replacement of the amplifier unit.
4.3.2.4 The shutter remains open only at "B" setting.
Undertake necessary check because this can be attributed to poor contact of the Bulb
switch (SW-6) or poor contact between the Bulb resistor of the VR-2 and the contact
piece.