Vivitar 283 Service Manual page 37

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11. TROUBLE:
No flash via PC cord- sensor on unit .
ACTION
A. Check jumper across pins A and B in sensor
. B. Check wires from sensor receptacle to PC
board B
C.
Check for trigger voltage at PC cord recep-
tacle contacts-PC spring
(+)
synchro con-
tact spring (-)
INDICATION
GOOD
Faulty
GOOD
Defective
No voltage
Automat ic Electronic Flash
Model 283
REMARKS
Go to step B
Repair
Go to step C
Repair or replace
Check
D5, R 12, trig-
ger coil T2, and trigger
capacitor C7
12. TROUBLE:
Flash works only in manual mode- full light output in auto mode- auto circuit not
working.
ACTION
INDICATION
REMARKS
A. Substitute test sensor and check unit in auto
Unit operates in
Defective sensor; check
mode
automatic mode
connections; repair or
replace sensor assembly
as required
Problem not
Check wiring from sen-
corrected
sor receptacle
to PC
board B and repair, if
required. If no defect
evident, proceed to step
B
B. Check thyristor SCR2 for short; resistance
Short
Replace SCR2
between anode and cathode should read OPEN
GOOD
Test auto
circuit per
procedure starting with
step C
C. Short circuit anode to cathode of SCR3, momen-
OT l should
If it does
not, replace
tarily
fire
OTl
If it fires, replace
go to step D if auto cir-
cuit still does not work
D. Replace trigger coil T3; check C 19 and replace Unit works in Problem solved
if defective
auto mode
Problem not Check power supply to
corrected R28, R29, and R31
Vlvltar 37460596 ( 11/80)
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