|
kq8service manual download site
kq8service manual download site
+ 10 v over voltage protection: when the remote control is special 10 v output power abnormally elevated, D857 reverse breakdown, make A point potential write - > B point potential left - > C point potential write down the CPU to enter standby state protection. kq8service manual download site
kq8service manual download site
Line output over-current protection principle: when the line output stage flow, the pressure drops of over current sampling resistor R557 made Q553 is partial and conduction, its c an output high voltage breakdown conduction D551, make A point potential write - > B point potential left - > c point potential write down the CPU to enter standby state protection. kq8service manual download site
kq8service manual download site
High overpressure protection principle: when the ultrahigh pressure protection abnormally elevated line (that is, the output tube Q552c extremely negative peak pulse rise), will make D554 reverse breakdown, the pulse after D553 rectifier output high potential, make the diagram C point potential write - CPU to enter standby state protection. kq8service manual download site
kq8service manual download site
Field output over-current protection principle: output amplitude is too large or C454 appear short circuit on the spot, in flow sampling resistor R454, R462 high voltage will appear and make D452 reverse breakdown, point A potential write to point B in figure left - > C point potential write down the CPU to enter standby state protection. kq8service manual download site
kq8service manual download site
From the above analysis shows, whatever the reason caused abnormal voltage 300 V, 140 V, 10 V lines with high voltage over voltage or, field output stage flow phenomena, will make A point in figure 0.7 V high potential, thus make Q856 is partial to listen to the dark saturated conductivity, the diagram B point potential reduced to 0 V, prompting Q857 conduction, its extremely high voltage output to the CPU c 6 feet implement protective shutdown, 33 feet potential reduced to 0 V. Q857c extremely high potential at the same time maintain B R859, D859 to Q856b point potential of 0 v (locked), make Q852 cut-off, relay RL801 release, the machine electricity (except special remote control 10 v power supply) in to protect the state, the second boot is invalid at this time. Visible in the figure A, B, C point potential changes reflect the working state of the protection circuit, as long as by monitoring the above three potential, can quickly judge the fault position.
3 Home Previous 1 2 3 Next Last |