HarmanKardon-AVR20-avr-sb维修电路原理图.pdf

harman/kardon Service Bulletin Service bulletin # 9706 November 1997 Warranty labor rate: MINOR repair To: All harman/kardon Service Centers Models: AVR 10/20/25/3250; AVI 100/150/200 Subject: Remote Control has stopped working In the event you receive a complaint about a remote control that has stopped working, perform the following tests: 1) Remove the batteries and confirm they are not weak or defective (battery voltage should be 1.4 volts or more). Replace batteries if necessary; both batteries in remote control should be replaced. 2) Point the remote towards the corresponding receiver/amplifier and confirm the remote control functions operate as intended. 3) If Remote Control still doesnt work: Remove batteries, and with an alligator clip lead or other jumper wire, short the positive and negative tabs inside the control together. (See drawing) This short will drain any remaining charge from the capacitors in the remote control and re-set the microprocessor. 4) Re-insert batteries and test the functions as per item (2) above. NOTE: This procedure may also work for other h/k model remote controls not listed above. harman/kardon Incorporated 250 Crossways Park Drive, Woodbury New York 11797 (516) 496-3400 RadioFans.CN 收音机爱 好者资料库harman/kardon Service BulletinService bulletin # 9502 - February 1995Warranty labor rate: MAJOR repairTo: All harman/kardon Service CentersModels:AVR-20/AVI-150 Surround receiver/amplifierSubject: Low impedance protect circuit, intermittend shut down.The power rating for the AVR-20 and AVI-150 is 60 Watts into 8 Ohms. The AVR-20 and AVI-150protection circuits will not activate until the loudspeaker impedance drops below 4 Ohms. Duringtransients in certain CD program material, the instantaneous impedance of some loudspeakers withimpedance ratings of “8 Ohms” can drop well below 4 Ohms. As result, the low impedance protectioncircuit will be activated.In the event you receive from a consumer one of these products with the complaint “unit shuts downintermittendly” change the components indicated in the table below. After the change, confirm the idlingcurrent by measuring the voltage between the emitters of the output transistors. The test points areTP1/TP2 and TP3/TP4. The voltage reading should stabilize at 26 mV after the unit has been switched onfor at least 15 minutes. If needed, adjust idling current potentiometers VR251L/VR251R until you read 26 mV.ChangeFromToPart #Driver Transistor Q214L/214R2SC2690(A)2SC4883(A)2028307101Driver Transistor Q215L/Q215R2SA1220(A)2SA1859(A)2028007101Power Transistor Q216L/Q216R 2SC3181 (O)2SC3182(O)2028307101Power Transistor Q217L/Q217R 2SA1264(O)2SA1265(O)2028007101Resistor R244L/244R1.8kOhm1.8kOhm 1/8 W GD05182160Resistor R243L/R243R2.2 kOhm2.0 kOhm 1/8 W1-118-202-25Capacitor *C223L/C223R0.068mfd10.0 mfd 16 V E510601610*Minus to emitter of Q218L / Q218RRadioFans.CN 收音机爱 好者资料库harman/kardon Service BulletinService bulletin # 9601 -January 1996Warranty labor rate: MINOR repairTo: All harman/kardon Service CentersModels:AVR-20/AVR-20II Surround receiver/amplifier AVR-25/AVR-25IISubject: Poor or intermittent reception of FM_In the event you receive a unit from a consumer with a complaint “FM cuts out intermittently” use theprocedure listed below in addition to the procedure listed in the service manual for FM alignment.To supplement the manual, for FM center tuning alignment follow these procedures;AVR20/AVR20IIAlignmentEquipment settingsAdjustAdjustForQuadratureTune to a known strong FMstation around center of theband (98.1MHz)T8030 VDC across R809, confirm by tuning toanother strong station.Repeat step 1 in service manual for minimum distortion. Repeat both steps again for optimum sensitivity.*note: step #4 in AM IF states adjustment point VR802, should be VR801 step #2 in FM IF states adjustment point VR801, should be VR802AVR25/AVR25IIAlignmentEquipment settingsAdjustAdjustForQuadratureTune to a known strong FMstation around center of theband (98.1MHz)T9030 VDC across R914, confirm by tuning toanother strong station.Repeat step 1 in service manual for minimum distortion. Repeat both steps again for optimum sensitivity.harman/kardon Incorporated, 80 Crossways Park West, Woodbury, New York 11797 (516) 496 3400