|
iFkservice manual download site
Third, to cut off the control circuit. Q803 for standby control tube, conduction for standby, Q802 control at the same time, the voltage on the C817 decoupling D803 complement to light, the sustain oscillations of switch power supply, output a + B low voltage (about 30 v). The Q803 dismantle or will the base circuit disconnect, namely cut off the standby control circuit. iFkservice manual download site
Four, the protection circuit and control circuit, after separation can be like a conventional circuit switch power supply for maintenance. IC802, Q801, optical coupling D803, IC803, T801 switch oscillation and voltage stabilizing circuit. If the voltage stability performance is poor, can check the following components: C812, C813, D803, IC803, IC802. If the start is difficult, can check the following components: R805, R806, C811, R807, R866. Inspection found that some color TV set, using years because IC802 (STR - S6307) aging and its ability to enlarge, start and load ability is insufficient, can be in C811 parallel capacitor, a 223 p on incentives to increase the current. Improve IC802 oscillation conditions that enable switching power supply to work properly. A sign of switch power supply is normal work is: after electrify, 60 w bulb light up quickly, at the same time, a loudspeaker normal rustle (not antenna, high at this point, put, put, sound circuit should work). + B should be 113 v voltage measurement, the other two groups and 16 v voltage of 46 v or so. If a + B voltage deviation is not more than 5% can be treated as the normal range, does not cause protection circuit. Will be resumed Q803 access circuit, standby control, at this point, the bulb light and can be closed with the remote control. Listen to switch power supply should be no "squeak" sound, if have sound, should check the filter capacitor C809, C815, C835 mainly. After normal work, switch power supply will be resumed protection circuit, Q804 access circuit, energized again, if not light bulb, specify in the protection circuit itself. Should be focusing on the following components: Q826, Q827, D836, D811, Q805, D831.
4 Home Previous 1 2 3 4 Next Last |