Panasonic KX-FLB802CX Service Manual

67KX-FLB802CX/KX-FLB812CX/KX-FLB802CXS/KX-FLB812CXS6.18. POWER SUPPLY BOARD SECTIONThe power supply board circuit generates +3.3V, +6V, +12V and +24Vdc. It also suppliesAC voltage to the halogen heat lamp in the fuser unit.The power supply board uses the switching regulator method.[Input Circuit]The input current goes into the input rectifier circuit through the filter circuit.The filter circuit decreases the noise voltage and the noise electric field strength.[Rectifier Circuit]The input circuit is rectified by D10 to D13 and charge C5 to make DC voltage.Then it supplies power to the converter circuit.[Kick-on Voltage Circuit]Bias is applied to the Q1 gate via this circuit when the AC power is turned on and Q1 begins operating.[Surge Absorber Circuit]This circuit is for absorbing surge voltage generated by the transformer.[Over Current Limiter (O.C.L)]The highest drain current of Q1 is limited by a limit current circuit. The 24V output is limited by this circuit.[Over Voltage Circuit]If the 24V output increases because the error detecting circuit or control circuit is broken, Control circuit will recognize this signaland output becomes 0V. D104, D275 and D503 also prevent over voltage.[3.3V Output Circuit]This circuit is composed of DC-DC converter method.Dummy load method (to quickly check the power supply output)Refer to POWER SUPPLY BOARD SECTION (P.189).20 102 66 67 30 1E 114 9 0921 100 64 68 29 1D 115 9 0922 97 61 69 28 1C 116 9 0923 95 5F 70 27 1B 117 8 0824 93 5D 71 27 1B 118 8 0825 91 5B 72 26 1A 119 8 0826 88 58 73 25 19 120 8 08Temperature[C°]AD value HEX reading Temperature[C°]AD value HEX reading Temperature[C°]AD value HEX readingInputCircuitACInputC5GH12V24VKick-onVoltageCircuitEF3.3V6VDGNDHTRCTLPGNDControlCircuitR2R3R4R41 ConverterCircuitCDRectifierCircuitAB+Error DetectingCircuitSurgeabsorbercircuitO.C.LQ1A-B Voltage Wave FormC-D Voltage Wave FormE-FG-H Voltage Wave Form000T1PC1TriacSCR51Heat Lamp Photo TriacCoupler PC2Block Diagram+++3.3VOutputCircuit