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HBXservice manual download site
HBXservice manual download site
(2) the line output over current detection circuit composed of line output current sampling resistor R557 (0. 22 Ω) and test tube Q553 and peripheral components. Output circuit is normal, the voltage drop on the R557 smaller, Q553 cut-off, affect to protect circuit; When the line scan circuit, short circuit, leakage fault occurring cause line output current increases, the voltage drop on the R557 increase, forcing Q553 conduction. Conduction voltage R582, R553, R552 after partial pressure, will be 10 v voltage regulator tube D551 breakdown, to protect triode Q856 base provide the forward voltage, make Q856 conduction, control switch machine tube Q852 base between low, causing Q852 cut-off, television to enter standby mode. HBXservice manual download site
HBXservice manual download site
(3) the output fault detection circuit consists of a voltage regulator tube D452 and D459, D451. Output circuit failure occurs on the spot, the field current is too large, the output pulse voltage is too high, or C454 breakdown leakage, voltage regulator tube D452 breakdown conduction, current flows through D459, D451 added to protect pipe Q856 base, make Q856 conduction, the television into protection state. HBXservice manual download site
HBXservice manual download site
(4) vice power over voltage detection circuit consists of voltage regulator tube D857 and R867. Deputy normal output voltage, voltage regulator tube D857 cut-off, affect to protect circuit. When vice power supply voltage is too high, D857 breakdown conduction, after conducting the voltage through R867 added to protect triode Q856 base, make Q856 conduction, television to enter standby mode. HBXservice manual download site
HBXservice manual download site
(5) the output flow and pressure detection circuit composed of partial pressure circuit and D554. Line output pipe Q552 collector in C555, C567 midpoint of pulse voltage resistance R564, R565, R563, R566 and stabilivolt D555 partial pressure, with R564 and R565 midpoint as a line of the output pulse voltage sampling point, added to the voltage regulator tube D554 cathode. Normal point when the voltage is lower than the voltage value of the voltage regulator tube D554 36 v, D554 cut-off, affect to protect circuit. When the power supply output line + 140 v voltage is too high or flyback capacitance open circuit and other reasons, causing the output pulse voltage line rise, may damage the delivery pipe, the partial pressure point voltage is raised. Partial pressure point voltage above 36 v above will D554 breakdown, after the breakdown of the voltage by R567 D553 to micro, straighten out the 6 foot protection test end, 6 feet from normal low level to high level, the microprocessor into protection state accordingly.
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