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Refer to the “SCHEMATIC DIAGRAM”.
4 CIRCUIT DESCRIPTION
4.1. Operation for control circuit power supply
When the position of the rotary switch A is changed from OFF to other position (AUTO/C AUTO/MANUAL/SLAVE), RQ2 turns ON.
Then it starts to supply the control power.
4.2. Operation for converter oscillation circuit
When the position of the rotary switch A is changed from OFF to other position (AUTO/C AUTO/MANUAL/SLAVE), Q3 turns ON,
and then Q1 and Q2 are started to oscillate. That is started to charge C3 through T1 and D2. Then power is supplied to control
circuit through D1 and R53.
4.3. Operation for constant voltage control circuit
When charging voltage becomes 275±5 V after C3 is started to charge, the voltage between R6 and R32 is to be 2 V. That make
1 pin of IC2 be opened, then LD1 is lit up.
When charging voltage is 330±5 V by charging voltage of C3 is increased more, the voltage between R32 and R33 is to be 1.7 V.
The voltage is detected, and then 7 pin of IC2 is L, RQ1 is ON. Between (E) and (B) of Q1 and Q2 is shorted, oscillation is stopped.
When the voltage between R32 and R33 is fallen to 1.65 V after oscillation is stopped, 7 pin of IC2 is opened. Then oscillate again.
The voltage of C3 is maintained between 325 - 330 V because above operation is repeated.
4.4. Operation for flash circuit
Press the test flash button (SW3 is ON) or X terminal is to be L, Q7 is ON and SCR2 is ON through R26. Then electric charge of
C14 is flowed the following.
· (A) of SCR2→ (C) of SCR2→T2 COM→Primary→C14
After that, trigger pulse is produced at secondary of T2 and XE1 is energized. Thus make a flash. At that time, gate circuit of IT1
is always ON because the voltage of C3 is supplied to it through R18 and R19.
4.5. Operation for modulated light circuit
Q4 is ON by the energy of C4 after XE1 is flashed, the electric charge of C6 is supplied to modulated light circuit. In case of AUTO
mode, (E) of PT1 is connected to GND by the SW 1 and 2. then start to flash. When the received light of PT1 is proper, the base
current of Q5 is flowed through R13.
SCR1 and Q6 is ON at the same time after Q5 is ON, gate voltage of IT1 is to be L and stop to flash. (C AUTO is the same.) In
case of MANUAL mode, operation is almost the same. The base current of Q5 is flowed through TH1, TH2, VR1 and VR2, Q5 is
ON and stop to flash.
SCR1 is also glow light protection circuit. XE current is flowed through R20 and SCR1, Q6 keep being ON until SCR1 is OFF. IT1
keep being OFF is operated glow light protection circuit.
4.6. Operation for SLAVE circuit
When SW1 and 2 to SLAVE mode, RQ3 and 5 is ON commonly. Modulated light circuit is the same for MANUAL mode. RQ6 is
ON at the time RQ3 and 5 is ON, lock when received light is detected by other mode is canceled by Q10 is OFF.
When PD1 is received other flash light, 7 pin of IC3 is to be H and start to flash after SCR2 is ON through R44, D9. Change SW1
and 2 to GND, discharge the electric charge of C17 through D8 and make the flash stop by X contact between test flash button and
shoe.
4.7. Operation for auto check circuit
D3 is connected to GND through SW1 and 2 and RQ3 when the mode is selected except for AUTO and C AUTO. However RQ7
is locked, RQ7 is ON after Q5 is ON when the mode is selected AUTO and C AUTO. Then RQ8 is ON and auto check lamp is
lighted (LD2 is ON) within the time constant between R49 and C22.
4.8. Operation for flash prohibition circuit
When SW1-1 is OFF, between (C) of Q7 and R26 is connected to GND. Thus SCR2 cannot be ON is prohibited to flash when the
power is OFF.
20
DMW-FL28PP / DMW-FL28E