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Open the case , remove the ballast components, its visual inspection , no exceptions , and then focus on the relevant components detected no abnormalities in the road . Related to the printed circuit board cleaning after soldering points , will host the ballast on each plug and socket connection corresponding components on the test machine , when you start the projection lamp observed a sustained spark , and last longer can not enter the normal lighting condition, obviously not in line with the type of projector projection lamp ballast start-up time 1.4 seconds to 1.6 seconds regulations. Long start-up time , the projected life of the lamp and ballast circuit security components have a crucial impact on , the emergence of such phenomena should be immediately shut down, to find the real cause of the fault , in order to avoid greater losses .wq8service manual download site
Projected from the light bulb can produce sustained spark when you start judging , ignition ( high voltage generating ) circuit , auxiliary power circuits , chopper regulator ( the equivalent of his excited tandem switching regulator ) circuit , TWM control ( ie, pulse width control ) circuit, error calculation and testing circuits are normal, the fault is likely in the timer circuit or timer control circuit. The timing circuit of the ballast of the projector shown in the drawings . FIG R723, C711 based timing components , ZD701 and Q707 to the level detector and an electronic switch , RY702 terminal device is performed , Q706 corresponds to the start timing of the switching circuit , the main circuit controlled by a microprocessor instruction . After operating the start button , the main circuit power microprocessor sends instructions to enable conduction photocoupler PC701 , and Q706 b clamp the pole zero level , to promote Q706 is turned ON by the deadline . After Q706 conduction, voltage +13.5 v about through QT06e, c pole and then the R723 to C711 charge , after a certain time ( regular time parameters of the circuit elements approximately 1.4-1.6 seconds ) , C711 both ends of the voltage reaches the breakdown voltage ZD701 , ZD701 breakdown conduction , to impose a higher pole Q707 b o. 6v high level , Q707 saturated conduction its c -pole relay RY702 ¢à pin is set low, the relay is energized , cutting off its ¢Û, ¢Ü feet of ground firearms circuit , and the Start program ; simultaneously turned their ¢Ý, ¢Þ foot inverter pulse oscillation and frequency divider circuit , Q702 ~ Q705 composed of DC / AC inverter circuit by providing a bridge
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