HarmanKardon-AVI100-avr-sb1维修电路原理图.pdf

harman/kardon Incorporated 250 Crossways Park Drive, Woodbury New York 11797 (516) 496-3400 harman/kardon Service Bulletin Service bulletin # 9606 August 1996Warranty labor rate: MINOR repair To: All harman/kardon Service Centers Models: AVR-10 /AVI-100 Subject: Rear channel volume level _ While playing certain Dolby Pro Logic program material with low sensitivity rear channel loudspeakers, the perceived volume level from the rear loudspeakers may be lower than the volume level from the front speakers. To increase the volume level from the rear channel with approximately 5 dB, perform the following modification: 1) Locate the Surround Sound PCB, (PCB10) close to the rear of the product. PCB-10 is mounted vertically. Locate on PCB-10 IC304. IC304 is the Surround Sound signal amplifier. 2) Pin 6 of IC304 is connected to feedback resistor R353 (1K8). R353 is mounted vertically, located closely to pin 5 of IC304. The marking “R353” on the PCB is not directly next to the resistor. 3) Tack solder on the foil side of R353 a 2K2 resistor. This 2K2 resistor is now in parallel with the existing 1K8 resistor. Note: After the modification is completed, the combination of sensitive rear channel loudspeakers with a high setting of the rear channel volume may result in audible noise from the rear loudspeakers. RadioFans.CN 收音机爱 好者资料库