According to the real draw the camera flash oscillating circuit principle diagram (see figure). It is found in this machine oscillation transformer and trigger coils are integrated, and the trigger element is not controlled by a switch, but controlled by controllable silicon VS1. The flash oscillating circuit working principle is: switch on the power, the integrated block IC1 oscillation control signal sent to the triode V1 (2.7V in B, V1, V2, a triode V3, V4 have been conducting work to generate oscillation, can generate high voltage oscillations in the secondary of the transformer, C3 filter, VD1 rectifier diode for C11, C12 charge. When the flash, press the shutter switch, integrated block IC1 can send out a trigger signal (1.5V), the resistance of R7 to control thyristor VS1 pole to trigger conduction, capacitor C1 through silicon controlled and the primary circuit discharge trigger coil T2, in the T2 secondary to generate high voltage, excitation flash lamp light. The first table measured the triode V1 B highly integrated block IC1 2.7V output control signal, then measuring the voltage transistor V2, V3, V4, V4 of the B voltage is about 2.5V, B, e and suspected V4 open. Remove rear measurement has open circuit damage, find a D809 triode substitution after the failure remains. Ends with a voltmeter to measure C11 2.5V, this time with a touch after substitution of the tube D809 is particularly hot, checking other capacitance, resistance and other components are normal circumstances, to determine the basic oscillation transformer T1 damage, there may be a high-voltage coil winding inter turn short circuit. Due to the lack of the same type transformer replacement, the pin and the original circuit oscillation transformer connection line is cut off, use the oscillation transformer one other type of wire access circuit, power on test, still not, but with the measured voltage at both ends of the table C11 for about 60V, a triode D809 is hot, the oscillating circuit have basic work, but the voltage oscillation generated is insufficient to trigger flash tube light. After careful analysis, the problem may be in oscillation transformer substitution wiring properly, the lead replacement, again test machine, is heard a flash circuit oscillation squeak. Such squeak disappeared, according to the flash trigger key, light normal flash tube. Because there is no patch type switch triode, see between the circuit board and the casing position still can hold, the tube feet cut D980, and then to pin down welding to the circuit board. Without the removal of the original oscillation transformer (trigger coil T2 is good), the oscillation transformer replacement for lead is connected and fixed position in larger space installed the shell, flash work.

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