NPZ 1PN91-2, Service Manual

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29
Continuation of the table 8
Problem Possible reasons
Instruction on identifying
and elimination of the
assembly (detail) failure
and damage consequence
2 The IIT A2 has broken
down
3 The contacts have
oxidized or become
dirty
2 Send the sighting device
to the repair shop
3 Clean the contact and
wipe it with a napkin,
flannel or cotton wool
moistened with petroleum
solvent C2 80/20 of the
first class. Clean and wipe
the threading in the lid of
the sighting device case and
in the cap (Figure A.3)
Dark stains have
appeared in the field
of view of the sighting
device which prevent
its good operation
The IIT A2 (Figure A.) is
spoiled because of a flash
exposure to point light
sources; peeling-off on
the photocathode or the
image intensifier screen
has occurred
The sighting device must be
sent to the repair shop
When the sighting
device is switched on,
the image is blurred;
the IIT flickers or the
image is not stable
and fades
The IIT A2 is spoiled
b e c a u s e o f a f l a s h
exposure to some strong
light source
Switch the sighting device
off and keep it in a dark
place under OCC for two
days, the diaphragm 4
(Figure A.9) being put onto
the objective. If the sighting
device does not function
well after this time, send it
to the repair shop
6.2.2 Replace the cap (Figure A.5) in the following way:
– screw out the ring 2 with the help of the spanner 7 (Figure A.9) from the
single STA kit;
– take the cap off (Figure A.5) together with the bush which is under the
ring 2;
– replace the cap with the good cap 8 (Figure A.9) from the single STA kit;
– put the bush on its place and screw up the ring 2 (Figure A.5) with the help
of the spanner 7 (Figure A.9).
6.2.3 Replace the accumulators G and G2 (Figure A.) in the sighting device
in the following way:
– switch off the sighting device by turning the handle 2 (Figure A.3) to the
position marked with the red point;
– screw out the cap (Figure A.3) with the cup;