TM 11-6720-239-35
Corrections
Symptom
Probable trouble
Blade stays open on all speeds except
Replace capacitor C2.
Defective capacitor C2 . -. ---------
3000 when lighting selector control
is set to left (dull) position.
150 Dull very fast, on 75 Dull one stop
Repair connection between affected con-
Open circuit between positive (+) C2
fast.
tacts.
contact and selector switch (S5), C2
contact.
Clean switch rotor and contacts, adjust
Dirty or defective selector switch S5 --
contacts to touch rotor.
Replace capacitor C2 (para 3-6).
Defective capacitor C2 .. . . . .
Adjust potentiometer R3 or replace photo-
Incorrect trigger voltage -- . . . . .
All speeds either too fast or too slow. -.
cell V1 or both. (para 3-19 and 3-20).
FILM SPEED dial of aperture wheel
Adjust S2 (para 3-19).
Switch S2 out of adjustment-
Replace blades. (para 3-6).
150 or 300 dull too fast or too slow
Mechanical binding of blades --------
Lubricate cocking slide with lubricating wax.
or erratic.
Mechanical binding of cocking slide---
Clean magnet and keeper.
Rust or foreign matter on magnet or
keeper.
Clean S6 contacts with fine file.
Dirty switch S6 contacts .- -.
String jumper wire between affected con-
75 dull too fast, all other speeds
Open circuit between positive (+) C3
tacts.
normal.
contact and selector switch (S5) C3
contact.
Defective capacitor C3 ----------
Replace caparitor C3 (para 3-6).
Clean and adjust S4 contacts.
Open Contact between S4 center con-
tact and S4 contact connected to R4.
Open circuit in selector switch S5
Clean and adjust switch S3 contacts.
between C3 contact and common
contact.
75 dull too slow . . ___
Defective
capacitor
C3__
Replace capacitor C3. (para 3-6).
Defective capacitor C1 ___
3000 dull too fast or too slow- ----
Replace capacitor C1. (para 3-6).
Replace Photocell V1. (para 3-6).
Defective
Photocell
V1
--------
Blades close together on 3000 dull
Resolder capacitor C1.
C o l d - s o l d e r e d capacitor C1 -------
Defective capacitor C1 __--
only.
Replace capacitor C1. (para 3-6).
Dirty or maladjusted switch S6 _
F-stop meter does not repeat within
Clean and adjust switch S6.
0.15 F-stops after inserting and
removing flash plug.
Defective or cold-soldered resistor R4
F-stop meter varies from specified
Replace or resolder resistor R4 or R7, or both.
to inch rise with flash plug
or R7.
inserted.
Flash test bulb does not fire_ .
String jumper wires between flash safety
Open connection in flash circuit-
switch and outside contact of flash jack
or between flash switch SX and inside
jack, or both.
contact
Clean or replace flash switches S3 and/or S4
Dirty or defective flash switches S3
as required.
and or S4.
Adjust potentiometer R3 or replace
Incorrect trigger voltage _____
75/50 dull does not conform to
photocell, or both, (para 3-19).
specifications.
a. Replace C2 or C3 (para 3-6).
75/50 dull 15 only one stop fast
a. Defective capacitor C2 or C3 --- .
b. String jumper wires between C2 or C3
b. Open circuits between C2 or C3 and
and their respective S3 contacts on
their respective S3 contacts on
switch S5.
light selector switch S5.
Replace capacitor C4. (para 3-6).
75/50 bright and 75/300 bright too
Defective capacitor C4 .. ---- ___ -----
fast or too slow.
Replace capacitor C4. (para 3-6).
75/50 bright and 75/800 bright too
a. Defective capacitor C4 _- --- ______
String jumper wires between positive (+)
fast only.
b. Open circuit between positive (+)
side of C4 and its contact on switch S5.
side of C4 and its contact on
light selector switch S5.
75/800 dull too fast or too slow --------
Adjust timing switch S2. (para 3-19).
Timing switch S2 out of adjustment_ ---
2-4
